PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.
MAY BE RECALLED with earlier due date if requested.

 

DATE DUE

DATE DUE

DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6/01 c:/CIRC/DateDue.p65-p. 15

 

MANUFACTURED HOUSING
PRODUCTION PLANT
LAYOUT-DESIGN PROCESS

By

Namita Mehrotra

A THESIS
Submitted to
Michigan State University
in the partial fulfillment of the requirements
for the degree of '
MASTER OF SCIENCE

Construction Management Program

2002

ABSTRACT

MANUFACTURED HOUSING PRODUCTION PLANT
LAYOUT -DESIGN PROCESS

By

Namita Mehrotra

Manufactured homes have come a long way, from the pre-World War II trailers to
one of the most preferred and popular forms of factory-built housing. In 1999, 21.4
million American lived in manufactured homes. Like other manufactured products, the
manufactured homes are built in a factory on an assembly line. The assembly line
consists of many activity stations supported by sub activity stations, feeder stations, and
storage areas. However, the space considerations for these assembly lines are not well
defined. Workers in the factory frequently must walk long distances in order to get raw
materials or tools for different activities. Visit to a factory and discussions with its
productions managers have revealed that these factories were previously warehouses or
other big storage spaces.

The goal of this research is to produce systematic guidelines for the design of a
layout for a manufactured housing production plant. For this purpose, the tools and
techniques available in the field of industrial engineering are adopted. Space and
proximity requirements in a production plant are understood and a layout design software
program namely FactoryPLAN, is used to prepare production line layouts. Based on the
complete process, layout design guidelines are produced in the form of a process

flowchart.

Dedicated to Ma, Papa, and Gudia

iii

ACKNOWLEDGEMENTS

I am thankful to Dr. Matt Syal for his support and advice during the last two
years. I am also thankful to Dr. Tariq Abdelhamid and Dr. Srinivas Talluri for their

help during this research.

I am thankful to Mr. Jim Vincent and Mr. Deepak Gokuldas for their help in

and technical assistance with the F actoryPLAN software.

I am very thankful to my wonderful parents, Usha Mehrotra and Vijay Kumar

Mehrotra, and my dear Sister Gudia, for all their love and support and for being there.
I am thankful to my dear friend and senior Omar Senghore for his continuous

support and guidance during the last two years. Finally I am very grateful to Vijay

Chitla, without whose help and support I wouldn’t have made it.

iv

TABLES OF CONTENTS

CHAPTER ONE: INTRODUCTION

1.1
1.2

1.3

1.4
1.5
1.6
1.7
1.8

OVERVIEW
NEED STATEMENT

1.2.1 INCREASE IN DEMAND OF MANUFACTURED HOUSING -
1.2.2 SHIFT IN DEMAND FROM SINGLESECTION HOMES TO
DOUBLESECTION HOMES
1.2.3 COMPETITION
1.2.4 TECHNOLOGY
1.2.5 EDUCATION
EXISTING RESEARCH
1.3.1 MANUFACTURED HOUSING
1.3.2 FACILITIES DESIGN
SCOPE AND UNIQUENESS OF RESEARCH
GOALS AND OBJECTIVES
METHODOLOGY
DELIVERABLES/OUTCOME
SUMMARY

CHAPTER TWO: LITERATURE REVIEW

2.1
2.2

2.3

2.4

INTRODUCTION
MANUFACTURED HOUSING
2.2.1 TERMINOLOGY
2.2.2 LITERATURE REVIEW
FACILITIES PLANNING AND DESIGN
2.3.1 TERMINOLOGY
2.3.2 LITERATURE REVIEW
SUMMARY

CHAPTER THREE: TECHNIQUES AND TOOLS FOR
MANUFACTURING F ACILITIES/PRODUCTION PLANT LAYOUT

DESIGN
3.] INTRODUCTION
3.2 TECHNIQUES USED FOR MANUFACTURING FACILITIES DESIGN

3.3

3.6

3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6

THE MANUFACTURING FACILITIES PLANNING PROCESS
OBJECTIVES OF PLANT LAYOUT

TRADITIONAL APPROACHES TO LAYOUT PROCEDURES
TYPES OF LAYOUT PROBLEMS

TYPES OF LAYOUTS

TYPES OF FLOW PATTERNS

SPECIFIC TECHNIQUES

3.3.1

SPACE REQUIREMENTS SPECIFIC TECHNIQUES

3.3.2 RELATIONSHIP CHARTS

TOOLS FOR PRESENTINGLAYOUT DESIGNS
TOOLS FOR DEVELOPING LAYOUTS

3.5.1
3.5.2
3.5.3
3.5.4
3.5.5
SUMMARY

ALGORITHM CLASSIFICATION
CRAFT

ALDEP and CORELAP
BLOCPLAN

AUTOCAD based design tools

CHAPTER FOUR: MANUFACTURED HOUSING PROUDCTION

PROCESS
4. 1 INTRODUCTION
4.2 STATION CLASSIFICATION

vi

4.3
4.3.1

4.4

4.5

4.6

MANUFACTURED HOUSING PRODUCTION PROCESS
FLOOR CLUSTER

4.3.2 WALLS CLUSTER

4.3.3 ROOF CLUSTER
4.3.4 EXTERIOR FINISHES CLUSTER
4.3.5 INTERIOR FINISHES CLUSTER
DATA COLLECTION FORMATS
4.4.1 SPACE REQUIREMENTS
4.4.2 RELATIONSHIP CHARTS
SOFTWARE AVAILABLE FOR LAYOUT DESIGN
4.5.1 BLOCPLAN '
4.5.2 FactoryPLAN
SUMMARY

CHAPTER FIVE: PREPERATION OF GUIDELINES FOR
PRODUCTION PLANT DESIGN

5.1
5.2
5.3

5.4

5.5
5.6

INTRODUCTION
PURPOSE OF GUIDELINE DESIGN
FLOWCHART
5.3.1 TYPES OF FLOWCHART
5.3.2 PLOWCHART SYMBOLS
GUIDELINES FOR MANUFACTURED HOUSING ASSEMBLY LINE
LAYOUT DESIGN
EVALUATION OF GUIDELINES
SUMMARY

vii

CHAPTER SIX: SUMMARY AND CONCLUSIONS

6.1 OVERALL SUMMARY
6.2 SUMMARY BY OBJECTIVES
6.2.] TO COMPILE THE PROCESS DETAILS OF
MANUFACTURED HOUSING PRODUCTION
6.2.2 TO DEVELOP SPACE AND PROXIMITY REQUIREMENTS
BASED ON THE PROCESS DETAILS
6.2.3 TO PRODUCE ALTERNATIVE LAYOUTS USING EXISTING
PLANT LAYOUT SOFTWARE
6.2.4 To FORMULATE DESIGN GUIDELINES BASED ON SPACE
AND PROXIMITY REQUIREMENTS DEVELOPED
6.2.5 TO PINALIZEDESIGN GUIDELINES BASED ON THE
INDUSTRY INPUT.
6.3 LIMITATIONS OF RESEARCH
6.3.1 LIMITATIONS OF LAYOUT DESIGN
6.4 CONCLUSIONS

6.5 AREAS OF FUTURE RESEARCH

REFERENCES

APPENDECIES

APPENDIX A
APPENDIX B

viii

LIST OF FIGURES

FIGURE 1.1: PLACEMENT OF NEW SINGLE AND MULTI SECTION HOMES
FIGURE 1.2: THE FACILITIES PLANNING PROCESS-MANUFACTURING
FACILITIES

FIGURE 1.3: SCHEMATIC RELATIONSHIP OF CONSTITUENT ACTIVITIES ON A
ROOFING

FIGURE 1.4: RELATIONSHIP CHART

FIGURE 1.5: MILESTONE FOR THE LAYOUT DESIGN PROCESS OF A
MANUFACTURED HOUSING PRODUCTION PLAN

FIGURE 3.1: FACILITIES PLANNING FOR A MANUFACTURING PLANT
FACILITY

FIGURE 3.2: SYSTEMATIC LAYOUT PLANNING (SLP) PROCEDURE

FIGURE 3.3 FLOW WITHIN PRODUCT DEPARTMENTS

FIGURE 3.4: FLOW WITHIN PROCESS DEPARTMENTS

FIGURE 3.5: GENERAL FLOW PATTERNS

FIGURE 3.6: FLOW WITHIN A FACILITY CONSIDERING THE LOCATIONS OF
THE ENTRANCE AND EXIT

FIGURE 3.7: DENDEITE FLOW PATTERN

FIGURE 3.8: FROM-TO CHART

FIGURE 3.9: RELATIONSHIP CHART

FIGURE 3.10: DISCRETE REPRESENTATION

FIGURE 3.11: CONTINUOUS REPRESENTATION

FIGURE 3.12: SPLIT AND UNSPLIT DEPARTMENTS

FIGURE 4.1: MANUFACTURED HOUSING PRODUCTION PROCESS

FIGURE 4.2: TYPICAL PRODUCTION PLANT LAYOUT

FIGURE 4.3: LIST OF DEPARTMENT AND RESPECTIVE AREAS IN BLOCPLAN
FIGURE 4.4: RELATIONSHIP CHART IN BLOCPLAN

FIGURE 4.5: DEPARTMENT SCORES

FIGURE 4.6: LENGTH/WIDTH RATIO

FIGURE 4.7: BLOCPLAN MAIN MENU

FIGURE 4.8: BLOCPLAN SINGLE STORY LAYOUT MENU
FIGURE 4.9: LAYOUT DEVELOPED IN BLOCPLAN

FIGURE 4.10: DRAWING PARAMETERS IN F ACTORYPLAN

FIGURE 4.11:

MAINMENU BAR

FIGURE 4.122CHARTS/DATA AND DIAGRAM FROM THE MAIN MENU BAR

FIGURE 4.13:
FIGURE 4.14:
FIGURE 4.15:
FIGURE 4.16:
FIGURE 4.17:
FIGURE 4.18:
FIGURE 4.19:
FIGURE 4.20:
FIGURE 4.21:
FIGURE 4.22:
FIGURE 4.23:

FACTORYPLAN DATA FILES

ACTIVITY/DEPARTMENT LIST

SPACE INFORMATION

RELATIONSHIP INPUT WINDOW

DRAW RELATIONSHIPS LINES

WORKCENTER POINTS

FACTORYPLAN SCORE

TYPES OF SCORE

E SCORE VS. WEIGHTED SCORE FOR PRODUCTION PLANT A
E SCORE VS. WEIGHTED SCORE FOR PRODUCTION PLANT B
S SHAPED LAYOUT FOR PRODUCTION PLANT A

“Images in this thesis are presented in color”

LIST OF TABLES

TABLE 1.1 SHARE OF FACTORY BUILT HOMES IN THE TOTAL HOUSING
SECTOR

TABLE 12; INCREASE IN UNITS PRODUCED AND PLANTS

TABLE 13: TOP FIVE MANUFACTURED HOME BUILDERS IN 2000

TABLE 1.6: DATA COLLECTION FOR SPACE REQUIREMENTS

TABLE I7: DETAILED DATA COLLECTION TABLE FOR SPACE
REQUIREMENTS '

TABLE 3.1: AISLE ALLOWANCE ESTIMATES

TABLE 4.1: SPACE REQUIREMENTS STATION N0: 6

TABLE 42; DESCRIPTION OF ALL MAIN ASSEMBLY, SUBASSEMBLY AND
FEEDER STATIONS

TABLE 43: CLOSENESS RATINGS

TABLE 4.4: REASON/CRITERION BEHIND CLOSENESS VALUE

TABLE 45: REASONS FOR ASSIGNING E OR I RELATIONSHIP BETWEEN
STATIONS .

TABLE 4.6: RELATIONSHIP CHART FOR PRODUCTION PLANT A

TABLE 4.7: DEFAULT SCORE FOR THE RELATIONSHIP CODES

TABLE 4.8: FACTORYPLAN DATA FILE

TABLE 4.9: STATION DESCRIPTION

TABLE 410: LAYOUT PATTERNS EXPLORED

TABLE 411: PROXIMITY SCORES FOR LAYOUTS OF PRODUCTION PLANT A
TABLE 4.12: PROXIMITY SCORES FOR LAYOUT OF PRODUCTION PLANT B
TABLE 4.13: POINTS BASED CLOSENESS RATINGS

TABLE 4.14: RELATIONSHIP CHART FOR RELATIONSHIPS SATISFIED IN 'S'
SHAPED LAYOUT AT PRODUCTION PLANT A

TABLE 4.15; RELATIONSHIP CHART FOR RELATIONSHIPS SATISFIED IN 'U'
SHAPED LAYOUT AT PRODUCTION PLANT A

TABLE 4.16: RELATIONSHIP CHART FOR RELATIONSHIPS SATISFIED IN '2'
SHAPED LAYOUT AT PRODUCTION PLANT A

xi

TABLE 4.17: RELATIONSHIP CHART FOR RELATIONSHIPS SATISFIED IN
'STRAIGHT LINE LAYOUT AT PRODUCTION PLANT A

TABLE 4.18: RELATIONSHIP CHART FOR RELATIONSHIPS SATISFIED IN 'L'
SHAPED LAYOUT AT PRODUCTION PLANT A

xii

CHAPTER ONE

INTRODUCTION AND PROPOSED RESEARCH

1.1 OVERVIEW

Manufactured homes haVe come a long way from the pre-World War H trailers to
one of the popular forms of housing. In comparison to the mobile homes of the past,
today manufactured homes vary in design and appearance and are often mistaken for
conventional Site-built homes. Manufactured homes, which were previously placed in
mobile home parks, have now found place in privately owned lots too. In 1999, over 68
percent of manufactured homes were placed on private property, while the remaining 32
percent were sited in residential land-lease communities (MI-II-l). Research in the area of
manufactured housing has also shown that more Americans are living full-time in
manufactured homes. In 1999, 21.4 million Americans lived in manufactured homes. In
addition, 88% of the owners of manufactured homeowners were very satisfied with their

housing preference (MHI- l ).

In the 19905, the demand for manufactured homes grew tremendously, although it
has shown a downward trend in recent years. Table 1.1 shows the different types of
factory-built homes and their share in the housing sector. In 1998, about 22.7% (MI-II-Z)
of the housing sector was dominated by manufactured housing, followed by, modular,
panelized, and pre-cut housing sectors. Affordability is one of the major factors for this
success. In addition, homebuyers get a chance to choose from a variety of features when

they decide to purchase a manufactured home.

Table 1.1 Share of factory built homes in the total housing sector
(Willenbrock 1998, MHI-2, AUTOB 2002)

 

 

 

 

 

 

 

 

Housing Type 1986 1993 1998 2001
Precut 3.0% 3.3% 3.3% 3.2%
Panelized 7.0% 6.7% 6.3% 6.2%
Modular 2.4% 3.3% 3.4% 2.9%
Manufactured 16.3% 18% 22.7% 18.9%

 

Manufactured homes can be classified into Single-section and double-section
homes. Double-section homes are manufactured as two separate single-section
modules/units and after production they are transported to the site individually. At the
site, they are re-joined and connected to utilities. Some homes are manufactured as
multiple-section homes (more than double-section) also. Single-section homes are
typically 16’0” wide with a total area of 1200 sq.ft. whereas, double-section homes are
about 32’0” wide with an average area of 15SOSq.ft. In 2000, 273,000 manufactured
homes were installed, of which 87,200 (32%) were single-section homes and 183,600
(67.25%) were double-section homes (Census, 2000). Also, in 1999, a single-section
home with an average area of 1,245 sqft. cost about $ 31,800; whereas a double-section
home with an average area of 1,605 sqft. cost about $ 50,200 (MI-1L3).

The manufactured home, as the name suggests, is manufactured in the controlled
environment of a factory. From Station One where the chassis is brought in to the factory
to the final station where the home is cleaned up and material to be delivered to the site is
placed inside, the home goes through five separate stages where each of the major
elements (such as floors, walls, etc.) are installed. The assembly-line techniques remove

many of the problems of the Site-built sector. Each home meets the codes and

construction standards specified by the federal government and is very similar to a site

built home in appearance.
1.2 NEED STATEMENT

The manufactured housing industry has been going through many changes in the
past few years. There has been an increase in the demand for manufactured housing and
more people are choosing double-section homes rather than single-section homes. In
addition, manufactured homes have become a popular and affordable Option to permanent
housing needs. Because of the increase in demand and shift to double-section housing,
more production plants are being opC=ned. In addition, the old production plants, which
were primarily used for single-section home production, have been either expanded or
redesigned. Therefore, there is a need to understand and prepare proper guidelines for the

layout design of a manufactured housing factory.

1.2.1 INCREASE IN DEMAND FOR MANUFACTURED HOUSING

The history of manufactured homes Starts in the 19203, when the first trailer-
coaches were built. These were made for travelers on vacation who wanted tO' rest in
something better than a tent. After World War II, when the Veterans came back from the
war, they found both jobs and affordable housing nonexistent. The mobile housing
industry, as it was then called, fulfilled their requirements by building homes that were
large enough to house a family, yet mobile enough to move the trailer to new job sites. In
the 1960s, as the demand for these homes grew, the need for bigger trailers with more

conveniences and the new appliances also grew. Mobile homes were now bigger, had a

better appearance, and met the needs and demands of young homeowners. In June 1976,
the United States Congress passed the National Manufactured Housing Construction and
Safety Act (42 U.S.C.). This act required that beginning in 1976, Housing and Urban
Development (HUD) authority assured that all manufactured homes were built to strict,
consistent national standards (Anzer, 2002). In 1999, the industry shipped 338,200 homes
from 337 manufacturing facilities (MHI-l). Table 1.2 shows the increase in both the
number of units produced and the number of plants producing manufactured homes, a
clear indication of the growing demand in the industry. Though in recent years the
demand for manufactured homes has not grown, the author feels that by providing
guidelines for layout design of a production plant, the construction of efficient plants will
be facilitated. These better-designed plants would help in the production of more
affordable manufactured homes and, the more affordable the homes are, the greater the

demand for the homes will be.

Table 1.2: Increase in units produced and plants
(Census, 2000; MPH-3)

 

 

Year Total Units Produced Number of Plants Producing Units
1994 290,900 269
1995 3 19,400 285
1996 337,700 313
1997 336,300 323
1998 373,700 330
1999 338,200 337

 

 

 

 

 

1.2.2 SHIFT IN DEMAND FROM SINGLE-SECTION HOMES TO DOUBLE-
SECTION HOMES
There has been a growing demand for homes. More and more people look at
manufactured homes as an option for permanent housing and expect manufactured homes
to be similar in size, appearance, and standards to site built homes. Double-section homes
were first introduced in 1969 and since then have captured a large share of the market,
while single-section homes have become less popular. The increase in demand for the
double-section homes can be mainly attributed to the following two reasons (Bernhardt,
1980)
o The acceptance of manufactured homes as a permanent rather than transient form of
housing.
0 The relaxation of restrictions regarding width of the manufactured homes and hence

the permission to transport wider sections on the highways.

In 2000, multisection home shipments outpaced single-section home shipments,
making up 70.1 percent of total shipments (MI-Il-l). Figure 1.1 Shows the increase in
demand for double-section homes over Single-section homes. However, the facilities in
which manufactured homes are built have not changed adequately. Many of the present
production plants were actually designed for single-section homes. When the demand for
double-section homes grew, the same production plants were changed to cater to new
demands. These plants were only slightly modified by additions to the existing facilities

or use of more external storage areas for the raw materials. In addition, with the increase

in demand for multi-section manufactured homes, the existing facilities for housing

construction have proven less efficient, and in some cases, even unusable.
1.2.3 COMPETITION

Manufactured housing has been one of the fastest growing housing Options. A

greater number of homes are being built each year. A few top manufacturers produce

 

 

 

 

 

 

 

 

 

 

 

 

 

Placement of New Manufactured Homes
250
M
E 200 f $-
2 150 r +smgle-wide Homes
+Double~wideH mes
i 100 a. 0
g 50
D
0 1 I _ I I r I
1994 1995 1996 1997 199a 1999 2000
Your

 

 

 

Figure 1.1: Placement of New Single and Multi Section Homes
(Census, 2000)

a large percentage of the homes. Table 1.3 shows the top five manufactured home
builders in the US. for the year 2000. These top-five producers manufacture 153,284
units, which makes up almost 60% of the total production of manufactured housing units.
The increase in demand and strong competition among producers also highlights the need

to have better and more efficient and state of art production facilities.

Table 1.3: Top five Manufactured Home Builders in 2000

 

 

(MPH-3)
Rankin Company Total Homes Dollar Volume
1 Champion Homes 50,145 $ 1,490,658,000
2 Fleetwood Enterprises 45,082 $ 1,145,595,000
3 Clayton Homes 23,402 $ 580,000,000
4 Oakwood Homes 22,936 S 741,238,000
5 Skyline Corp. 11,719 S 394,498,000

 

 

 

 

 

 

1.2.4 TECHNOLOGY

Automation and robotic technology are commonly used in many manufacturing-
related industries. However this is not true in the case of the manufactured housing
production facilities. Most production facilities, such as, automobile industry have
undergone tremendous improvement and have evolved not only into more efficient and
productive facilities but also into more technically up to date and advanced facilities. The
manufactured housing industry can learn many lessons from these industries.

The highly seasonal nature of the sale of the manufactured housing and the I
availability of semiskilled labor has led to the low level of mechanization in production
plant (Bernhardt 1980). Depending upon the capacity of the production plant being
designed, different types of equipment are used during the production process. A few of
the pieces Of equipment presently used in manufactured housing factory are forklifts,
narrow aisle trucks, mobile catwalks, crane systems for material handling, pneumatic

hammers and Staplers, power screwdrivers, and spray painters.

Despite the above—described needs trends, little effort has been made to study and
understand the planning and design processes of a manufactured housing production
plant. Therefore, the author feels that there is a need to understand the layout design
process and come up with guidelines for the layout design of new and more efficient

production facilities.

1.3 EXISTING RESEARCH

One major source of information regarding production plant design of
Manufactured Homes is Building. Tomorrow: The Mobile/Manufactured Housing
Industry by Bernhardt (1980). It provides some information on existing design concepts
used in manufactured homes production plants. No other research work has been done in
the area of manufactured housing production plant design and layout. However, there is
an extensive body of knowledge related to production facility planning and design in the
field of industrial engineering. Therefore, the author has divided the areas of possible
sources of information into two major topics, which are:

0 Manufactured housing
0 The manufactured housing industry (Burkhardt, Mireley, Syal 1996; Syal &
Mehrotra, 2001)
o The manufactured housing production process (Senghore, 2001; Abu
Hammad, 2001)

0 Facilities planning and design (Tompkins et al., 1996; Heragu, 1997)

1.4 SCOPE AND UNIQUENESS OF RESEARCH

The scope of the existing research is to develop design layout alternatives and
process guidelines for manufactured housing production plants. This author does not
attempt to address other issues related to the design of production plants (like
architectural design, site design and layout, HVAC systems, construction process or
materials). Also, this research work mainly attempts to address issues related to space
management and allocation. The author plans to visit and interview floor managers and
production engineers from two manufactured housing production plants for the purpose
of data collection for this research work

Though manufactured housing production plants are similar 'to most other
production plants, they differ from them in one unique way. In most production plants,
like those in the auto industry, the product to be manufactured is standard, defined by the
manufacturers, and not custom-built to meet the consumers needs. Each item produced on
the assembly/production line is same as the one produced before and after it. In the case
of manufactured housing production plant, each home produced is unique by itself. It is
designed based on the needs and requirements of the consumer. NO two homes that come
down the production line are same. They vary in aspects like design, size, height, types
and color of finishes etc. Hence, the assembly line in the manufactured housing
production plant needs to be flexible in order to adjust to the requirements of each home
being produced. This makes the production plant design of a manufactured housing

facility a unique problem.

10

1.5

GOALS AND OBJECTIVES

The overall goal of this research is to understand and develop layout design

process guidelines for a manufactured housing production plant. The major objectives

are:

5.

To compile the process details of Manufactured Housing production

To understand techniques related to manufacturing facility layout design

available in the field Of industrial engineering
To collect space- and proximity-related data, based on the layout design
techniques and manufactured housing production process details

To develop layout design for the manufactured housing production plant

4 (a) To acquire and understand appropriate plant layout design software
4 (b) To produce alternative layouts
4 (c) To evaluate alternative layouts

To formulate layout design process guidelines based on objectives 1 to 4.

ll

1.6 METHODOLOGY

As Tompkins et al.(1996) explains, the planning process of a manufacturing
facility can be subdivided into a series of phases and sub phases. The model in Figure 1.2
has been modified to match the scope of the present research, and the phases have been

adapted to respond to the objectives of this research.

 

 
 
 
     
 

Define the
product tO be
manufactured Formulate layout

 
 
  
 
  
 

   

. design process
Specrfy the guidelines based on
manufactunng objectives 1 to 4.
process

     
 

  
 
 

 

  

 

 

Determine Evaluate
interrelationships 011]- 5 alternative
among stations layouts
Prepare a Obj. 2 Obj. 4
~ - To produce
relationship chart .
alternative layouts

  
 
 
   
 

 

Obj. 3

 
 
  

    

Determine space

  

       
 

requirements To acquire and

for all understand

statrons Collect data for appropriate plant
space and layout design
proximity software
requirements

 

Figure 1.2: The facilities planning process-manufacturing facilities
Modified from (Tompkins et al., 1996)

12

The following section describes the different steps involved in meeting each of the above
objectives.
Objective 1: To compile the process details of Manufactured Housing production
Define the product to be manufactured

A complete housing module is the output Of a manufactured housing plant.
Manufactured homes can be classified into two types: the Single section home which is
usually 16’0” Wide, and the double section home which is usually 32’0” wide.

The author plans to review existing literature based on the design and production
of manufactured homes. Additional information will be obtained by visiting two

manufactured housing production plants in northern Indiana.

Spectfi the manufacturing process required to produce the product

Manufactured homes are built in a factory on an assembly line. The author plans
to study existing research works, like the research report written by Ayman Abdullah
Abu Hammad, (2001) “Simulation Modeling for Manufactured Processes in
Construction,” which provides details on identifying ways of improving the productivity
of the manufacturing process. This research work deals with the complete production
process, taking all stations into account. A report prepared by Omar Senghore (2001),
“The Production and Material Flow Process Model for Manufactured Housing,” deals
with the documentation of the production process and material flow in the manufactured
housing factory and comes up with a simulation model for this process. This research
focuses on a few critical assembly stations and subassembly stations. In addition, during

the visits to the manufactured housing production plants, the author plans to observe the

 

 

systematic production process. The production process at difl’erent production plants will

be compared and a generic model will be developed.

The steps described above will be followed to develop a systematic, detailed
description Of all the activities involved in the production of a manufactured home. These
activities are grouped into five major clusters: floors, walls, roofing, exterior, and
finishes. Each Of the clusters of activities takes place in one of the main assembly
stations, which are in turn supported by subassembly stations, feeder stations and internal
and external storage areas. The major activities that are included in each of these clusters
are as follows:

Floors cluster: The floors cluster mainly consists of two to three stations where the
installation of floor joist, HVAC systems and waterlines in the floor takes place. The
floor is insulated in these stations also.

Walls cluster: This cluster mainly consists of installation of both interior and exterior
walls with insulation. Some of the bathroom appliances are also installed in this cluster.
Roofing cluster: This cluster mainly consists of a substation where the roof truss is
fabricated (in some factories pre-fabricated roof trusses are used) and two main “stations
where the roof is placed over the house and roof deck, and insulation and shingles are
installed.

Exterior cluster: The exterior finishes are usually carried out simultaneously with the
roof decking. The major activities that happen at these stations are installation of doors
and windows, exterior boards and siding.

Finishes cluster: This cluster mainly consists of three to four Stations. Electrical,

mechanical and HV AC installations and inspections are carried out in the first two

14

stations. At the next station, carpeting is installed and the interior of the house is painted
or wallpaper is put up. Finally, axles and wheels, window curtains and appliances are

installed at the last station.

Objective II: To understand techniques related to manufacturing facility layout
design available in the field of industrial engineering
Determine the interrelationships among stations

The interrelationships among different activity stations can be understood in two
ways:

0 Referring to existing research by Omar Senghore (2001), “The Production and
Material Flow Process Model for Manufactured Housing” and another by Ayman
Abdullah Abu Hammad (2001) namely, “Simulation Modeling for Manufactured
Processes in Construction,” which provide details on identifying ways of
improving the productivity of the manufacturing process. An example illustrating
the roofing clusters is presented in Figure 1.3.

0 Visiting the production plants and preparing the relationship charts.

Constructing a home in a factory is a systematic process. Certain activities need to
be completed before others can begin. For example, the roof can only be installed
after the framework for the external walls has been put in place, which in turn can

only be done after the floor insulation and ductwork have been completed.

15

 

 

 

 

Roof Roof Cover _
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Figure 1.3: Schematic Relationship of Constituent Activities on a Roofing
Station
(Senghore 2001)

On the other hand, there are certain activities that can be carried out at the same
time as other activities. For example, the installation of external floorboards is usually
done at the same time as the carpeting is being installed inside the home. It is important
to understand that in the manufactured housing production process scenario certain

activities need to be completed before the home can be moved from one station to the

other.

Relationship chart
The relationship charts represent qualitative measure of flow (flow can be flow of
material, information, or people).

“The relationship chart describes qualitatively the degree of closeness that the

analyst feels should exist between difi'erent work centers ” (Sule 1988).

16

The Relationship Chart can be used to determine adjacency between departments.
If material flow is an important consideration, or if common supervisory control is
important, then a high rating between two departments suggests that these
departments should be geographically close to each other. The shape and size of the
departments limits the number Of departments that can be adjacent to one another

(Tompkins et al., 1996).
Determine the space requirements for all stations

Once the specific stations and their interrelationships in the production plant are
defined, their space requirements need to be understood. The visits to the production
plants will be utilized to collect the data. Floor plans will be referred and if required
spaces will be measured. Floor managers at these plants will be contacted and their
opinion on the space requirements and utilization will be collected. Inaddition, existing
work done in this area will be researched. The author will also meet with industrial
designers and architects and understand the methods and procedures used by them.

Space requirements will be determined primarily for work areas, worker
movement areas and equipment movement areas. The space requirements for individual
assembly stations, sub assembly stations, feeder stations, sub-feeder stations, and internal
and external storage areas also need to be determined. The following section describes
the major stations in the production plant and the factors that determine their space

requirements.

17

Assembly and subasSembly stations

The stations’ space requirements mainly depend on the size Of the home being
manufactured. AS the length of the homes varies from 40’0” to 72’0”, the space needs to
be flexible. In addition, aisle space requirement needs to be determined. Similarly,
depending upon the type of subassembly being assembled or placed, the space

requirements for the sub-activity stations will also nwd to be adjusted.

Feeder stations and storage areas

The space requirement for feeder stations and storage areas depends upon the amount of
inventory the manufacturer maintains both inside and outside Of the facility. The
inventory can be maintained on either a per-home basis or a number-Of-day basis. For
example, the internal storage for external boards is usually a week, whereas the inventory

for appliances is for a month.

Aisle allowance estimates

Planning aisles that are too narrow will cause congestion and safety problems and may
give rise to high levels of damage. Depending upon the type of material handling
equipment used and the activity being carried out, the aisle width can be determined. For
example, activities like carpet installation require little external space, whereas activities

like installation of external boards, doors and windows require more external space.

18

Equipment allowance estimates
The equipment used in a manufactured housing production plant can be classified into
two sections, namely (Bernhardt, 1980)

0 Equipment used at activity stations, which are very similar to the equipment used
in conventional home construction. This equipment mainly consists of pneumatic
hammers and staplers, power screwdrivers, spray painters, and mechanical glue
applicators.

0 Equipment used for material handling: their three major types of material
handling equipment used expansively in the production process. They are hand-
propelled conveyers (carts and dollies), self-powered conveyers (folk lifts), and
overhead equipment (overhead hoists and monorails).

Special area considerations if required will be included during the layout design of the

production plant.

Objective 1]]: To collect space- and proximity-related data, based on the layout

design techniques and manufactured housing production process details

Proximity relationships

The relationship chart method was selected as the basis for data interpretation for
activity interrelationships. The different steps involved in the construction of a
relationship chart are explained in chapter three. Figure 1.4 shows a basic relationship
chart, which presents the relationships between the major clusters of stations in a

manufactured housing plant.

19

Space requirements

Table 1.6 shows the format in which space requirement data is collected for the
major clusters. Once space requirements for major clusters are collected, the author will
subdivide each of the clusters into smaller spaces and gather area information for them.
Table 1.7 shows the different divisions for which space requirements for each activity

will be collected.

Objective IV: To develop a layout design for the manufactured housing production
plant

To acquire and understand appropriate plant layout design software

Production plant layout design software programs have come a long way from the
traditional layout design solutions, first developed in 19603. The following section first
describes a few of the preliminary layout design software solutions and then goes on to
cover more recent software programs in the later section. These software solutions are
discussed in detail in later chapters.

ALDEP: ALDEP uses the Relationship chart to determine the importance of station
proximity. It requires a threshold closeness rating. The selection procedure used
encourages stations that have high ratings to be close to each other. For example, if a
threshold rating of E is selected, then the I, O and U ratings are considered equally
unimportant. (Where A-absolutely necessary, E-especially important, I-important, O-

ordinary, U-unimportant, and X-undesirable).

20

 

 

 

 

 

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Table 1.6: Data collection for space requirements

 

 

Number Function Area (sq.ft.)
1 Receiving station 2000
2 Floor stations 8000
3 Walls stations 9000
4 Roofing station 7600
5 Exterior finishes stations 8600
6 Interior finishes stations 7500
7 Shipping station 2500

 

 

 

 

 

21

 

Table 1.7: Detailed data collection table for space requirements

 

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The placement procedure in ALDEP creates several alternative layouts. The user
must specify the length and width of the facility and the area of each station. The user is
also required to specify a sweep width. By changing this sweep width, the user can obtain
several different layouts. ALDEP then creates a grid on the facility and assigns a number
of grid squares to each station in proportion to its area. ALDEP creates a block layout by
placing stations in the order determined by the selection procedure and blocks out an
appropriate number of grid squares. After a layout is completed, ALDEP determines how

good the layout is by giving it a numerical score (Palekar, 1998).

CORELAP: CORELAP also requires relationship charts asan input. However, weights
must be assigned to the ratings in the Chart. These weights are called "closeness ratings"
(CR). CORELAP computes a total CR (TCR) for each station by summing all the CRs
associated with that station. CORELAP does not consider the building shape. The final
shape of the facility created depends on the placement of stations that CORELAP has

selected. The procedure begins by placing the first department in the center of the layout.

22

 

Each subsequent department is situated according to already-placed departments in the
position that gives the best placement rating. The arrangement with the best placement
rating is selected. After the layout is completed, CORELAP calculates a numerical score

for the layout. A small layout score indicates a good layout [Palekar 1998].

BLOCPLAN : This program accepts data input from both From-To charts and
Relationship charts, i.e. both quantitative and qualitative data are accepted. The major
purpose of BLOCPLAN is to generate and evaluate block type layouts in response to the
user-supplied data. BLOCPLAN also uses relationship Codes specified by Muther in

Systematic Layout Planning (Donaghey, 2000).

A UT OCAD based tools: These tools can be utilized for the purpose of layout design. The
factory products group at Engineering Animation, Inc. (EA1, 1999) developed software
that simplifies designing a new factory or improving an existing one. Three programs
(FactoryCAD, F actoryPLAN, and FactOIyFLOW) run inside AutOCAD and allow for
both qualitative and graphical analysis as well as provide valuable tools for creating a
layout [Owen 2002]. FactoryPLAN is a qualitative layout design tool, which like
BLOCPLAN uses Muther’s Systematic Layout Planning for design process. It allows the
user to position stations based on different flow patterns and does not restrict the
positioning of stations like other software programs. F actoryPLAN was used for
preparing layout design alternatives for the manufactured housing production plant in this

research work.

23

To produce alternative layouts

Once the layout design software solution is chosen for the layout design of a
manufactured housing production plant, layout alternatives will be developed for
different layout patterns based on the space- and proximity-related data collected fi'om
the two factories. Each of the layouts will consist of the major assembly, subassembly

and feeder stations.

To evaluate alternative layouts

An effective score analysis related tO- the selection of a layout from the alternatives will
be computed. This process will show the areas where each of the layouts could be

improved.
Objective V: To formulate layout design process guidelines based on objectives 1-4

Formulate guidelines using plant layout techniques

Once the interrelationships between spaces and space requirements are
determined, the designer needs to come up With different facility layout options. The
options can be better understood by preparing evaluation charts, in which nodal relations
of the graphical representation of the relationship chart and From-To charts are converted
into semi scaled-grid representations. The layout design process guidelines will mainly
consist of the major steps involved in producing layout design alternatives for a

manufactured housing production plant. Figure 1.5 presents the major steps involved in

24

the development of the guidelines. This flowchart outlines the important steps involved in

this research.

Input firm): the manufactured housing industry on plant layouts
The author plans to seek industry input for the evaluation of the layouts produced. In
order to get input from the industry the author will visit and interview the production

plant managers to get their comments about the layouts.

Input from industrial design consultants on process guidelines

The author also plans to contact leading industrial design firms in the United States, to
get their input on the procedures they have adopted to come up with the design of a
manufacturing facility. Based on their input, the layout design process guidelines will be

finalized.

25

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26

1.7 DELIVERABLES/OUTCOM ES

As an outcome to this thesis, the author plans to produce a systematic process
approach to the layout design of a manufactured housing production plant.
The other major deliverables would be:
0 Documentation of the complete production process of manufactured housing
0 Space and proximity requirements based on the process details
0 Description of appropriate layout design techniques and software
0 Process of guidelines and layout alternatives based on Space and proximity

requirements

1.8 SUMMARY

The manufactured housing industry has made a lot of progress in the last few
years; this progress has always been concentrated on the product that is being
manufactured. No attempts have been made to understand the requirements Of the
facilities in which the product is being manufactured. This thesis is an attempt better
understand this issue.

Through this proposed research, the author has tried to emphasize the need for a
systematic process in the design of a manufactured housing production plant. The
objectives and methodology in this research will result in better understanding of the
requirements and tools and techniques used in designing better production facilities for

the manufactured housing plants.

27

CHAPTER TWO

EXISTING LITERATURE REVIEW

28

2.1 INTRODUCTION

The literature in this chapter can be divided into two major categories: the
manufactured housing industry and facilities design and planning. Though, Senghore
(2001) has provided definitions for most of the manufactured housing related
terminology, the author has restated the definitions for the convenience of the reader. As
this thesis presents design and planning. of facilities from the industrial engineering
perspective, the author will also present both terminology and existing literature related
to this field. Each category is further classified into two areas, which are terminology and

existing literature.

2.2 MANUFACTURED HOUSING

The manufactured housing industry has helped alleviate to the ever-growing need for
afl‘ordable housing all over the world. Manufactured homes are a part of the family of
factory built housing; modular homes, panelized homes and the pre-cut homes are other

members.

2.2.1 TERMINOLOGY
This section is further divided into two areas dealing with terminology related to
manufactured housing, terminology related to the manufactured housing industry in

general and terminology related to manufactured housing as a product.

29

2.2.1.1 MANUFACTURED HOSUING INDUSTRY
The Michigan Manufactured Housing Association has introduced some of the following

definitions (MMHA, 2000):

Manufactured Home: A home on permanent chassis built in a controlled, factory
environment and designed to be used with or without a permanent foundation when
connected to utilities. Manufactured homes are built to the federal Manufactured Home
Construction Safety Standards, enforced by the Department Of Housing and Urban
Development (HUD) in Washington, DC. Manufactured homes are single story and are
delivered to the home site in one, two, or occasionally, three sections; they may be placed

on private property or in a manufactured home community.

Manufactured Home Communities: Private land developed as homes sites for
manufactured homes. In Michigan, most sites are leased to the homeowner for a monthly

fee. They are sometimes referred to as a land-lease communities.

Single-Section Home: A manufactured home delivered to the home Site in one intact

section; the average square footage is 1,130 square feet.

Multi—Section Home: A manufactured home delivered to the home site in two or three
sections. The average square footage is 1,640 square feet, but multi-section homes may

be as large as 2,400 square feet. It may have a (site-built) garage attached after the home

is installed.

30

Manufacturer: Any person engaged in manufacturing or assembling manufactured

homes, including any person engaged in reselling of manufactured homes.

HUD Code: Code developed by the Department of Housing and Urban Development.
The HUD code regulates the home’s design and construction, strength and durability,
transportation, fire resistance, energy efficiency, and quality control. It also sets stringent
performance standards for the heating, plumbing, air-conditioning, and electrical systems.
The HUD Code specifically preempts local building codes as they relate to construction

codes for manufactured homes.

International Residential Code: Code provisions for one- and two-family dwellings
which apply to the construction, alteration, movement, enlargement, replacement, repair,
equipment, use and occupancy, location, removal and demolition of detached one- and
two-family dwellings and multiple single family dwellings (townhouses) not more than
three stories in height with a separate means of egress and their accessory structures

(IRC, 2001).

2.2.1.2 MANUFACTURED HOUSING PRODUCT & PROCESS

Manufactured homes are designed with one major objective: Provide a completely
furnished permanent housing unit that can be transported from the factory to the final
home site. A manufactured home as a product consists of a lot of elements/materials that
are similar to a site-built home, but there are other elements that are specific to the
manufactured homes. The following section defines some of these elements and

processes.

Foundation footing: Part of the support system located at or below ground level. Piers

are placed on foundation footings, which are made from concrete or treated lumber

(MMHA 2000).

Pier: The portion of the support system between the foundation footing and the

manufactured home, exclusive of caps, plates and shims (MMHA 2000).

Chassis: The structural base over which the manufactured home is constructed. It is
made of solid steel, an I-beam, a frame header, and outriggers to add extra support to load
bearing areas. The flame is sealed with rust-inhibitive black paint. The chassis ensures
the primary and continued transportability of the home. Once the house is installed, the
chassis receives all the vertical loads from the roof, walls and floor and transfers the load

to the foundation (Bernhardt 1980).

Marriage Wall: In a double-section manufactured home, the walls that are located where
the two sections join are called marriage walls. They are usually installed at a later stage
in the production process. The marriage wall is a double wall consisting of 2x4 studs.

Therefore, the marriage wall is an 8” thick centerline wall.
Single-station alarm device: An assembly incorporating the smoke detector sensor, the

electrical control equipment, and the alarm-sounding device in one unit (HUDMHCSS,

1999).

32

Anchoring equipment: The straps, cables, tumbuckles, and chains, including tensioning
devices, which are used with ties to secure a manufactured home to ground anchors

(HUDMHCSS, 1999).

Anchoring system: A combination of ties, anchoring equipment, and ground anchors
that will, when properly designed and installed, resist overturning and lateral movement

of the manufactured home from wind forces (HUDMHCSS 1999).

Diagonal tie: A tie intended to primarily resist horizontal forces, but it may also be used

to resist vertical forces (HUDMHCSS, 1999).

Ground anchor: Any device in the manufactured home that is designed to transfer

manufactured home anchoring loads to the ground (HUDMHCSS, 1999).
Stabilizing devices: All components of the anchoring and support system, such as piers,
footings, ties, anchoring equipment, ground anchors, and other equipment that supports

the manufactured home and secures it to the ground (HUDMHCSS, 1999).

Support system: A combination of footings, piers, caps, and shims that will, when

properly installed, support the manufactured home (HUDMHCSS, 1999).

33

Tie: Straps, cable, or securing devices used to connect the manufactured home to ground
anchors (HUDMHCSS, 1999).
Vertical tie: A tie intended to resist the uplifting or overturning forces (HUDMHCSS,

1999)

Factory-built fireplace: A hearth, fire chamber, and chimney asSembly composed of ‘-.-
listed factory-built components assembled in accordance with the terms of listing which

form a complete fireplace (HUDMHCSS, 1999).

Running gear assembly: The subsystem consisting of suspension springs, axles,

bearings, wheels, hubs, tires, brakes, and their related hardware (HUDMHCSS, 1999).

Drawbar and coupling mechanism: The rigid assembly, usually an A frame upon
which is mounted a coupling mechanism, whihh connects the manufactured home's frame

to the towing vehicle (HUDMHCSS, 1999).
2.2.2 LITERATURE REVIEW-MANUFACTURED HOUSING

The existing literature in the field of manufactured housing can be mainly found
in related research projects, dissertations, magazines, and books. Like the subdivisions in

the terminology section, this section is again classified into two parts, literature related to

general manufactured housing and literature related to product and production process.

34

2.2.2.1 MANUFACTURED HOUSING INDUSTRY

Many sources of literature addressing the manufactured housing industry in
general are available, but Building Tomorrow: The MobileManufactured Housing
Industry (Bernhardt, 1980) is one of the only books available which discusses both
manufactured homes as a product and reports the industrial organization and cost and
price structures in different associated areas, like the manufactured home production
system, distribution system, the Community parks, and the supporting and regulatory
environment. Bernhardt, as a part of two major industrialized housing related research
projects, examined the status of the industry and became convinced that, unless the
building industry on its own initiative undertakes strategic restructuring of its own
business organization as well as of its supporting, regulatory and political environments,
it will attain no major performcmce improvements, ”ng maintains that low cost and high
quality shelter can be produced in high volume.

In his book Manufactured Homes — Making Sense of a Housing Opportunity
(Nutt-Powell, 1982), the authors express their views on manufactured housing policies
covering market demand and need, design and construction, costs, legal issues and public

acceptance of housing recommendations.
A report prepared by the National Association of Home Builders (NAHB)

Research Center, Inc., for the US. Department of Housing and Urban Development,

Office of Policy Development and Research, titled “Factory cmd Site-Built Housing A

35

comparision for the 21 “ Century ” (NAHB, 1998), offers information on several
important dimensions in the area of manufactured housing. The information is
categorized under the following headings, overview of the housing industry and recent
trends; 'characterstics of conventional and manufactured homes; household characterstics;
design and material characterstics; comparision of the regulatory processes; approval,
design, and inspection; code requirements, and finally the cost analysis. Based on the
recent growth of the HUD-code approved manufactured housing sector, the report also
suggests strategies using which home builders can improve efficiency, reduce production

costs and help deliver affordable homes to buyers.

Another report prepared by NAHB Research Center, called Home Builders'
Guide to Manufactured Housing (PATH, 2000) is a guidebook that provides conventional
builders and land developers with information on manufactured housing, focusing on
differences between manufactured and conventional homes that are likely to be
encountered in practice. The sections describe a variety of options for using these homes.
The report also covers issues related to finding a manufacturer, developing product
specifications, arranging potential contracts, working with local zoning and land-use
planning, considering installation and foundation options, improving the building on-site,

and understanding regulatory issues and consumer financing.
The College Of Architecture and Urban Planning at the University of Michigan,

published a report called the “Manufactured Housing Research Project” (MHRP, 1993),

in the form of six reports describing manufactured housing quality, manufactured housing

36

costs and finance, manufactured housing values, manufactured housing impacts on
adjacent property values, manufactured housing and the senior population, and

manufactured housing as a form of alternative ownership with innovative uses.

Another report prepared at the Construction Management Program, Michigan
State University (Syal & Mehrotra, 2002) introduces the different factory built housing
options available and describes trends and terminology related to the housing industry
both nationally and in Michigan in the first part. The second volume of the report is an
assessment of the site regulatory requirements that impact the use of manufactured

housing (Morzoski & Sambrae, 2002).
2.2.2.2 THE MANUFACTURED HOUSING PRODUCTION PROCESS

According to Partnership Advancement of Technology in Housing (PATH), the
manufactured housing industry has been lagging behind in its technological innovations
compared to site-built housing.

In 2000, a team from Michigan State University and the University of
" Cincinnati was funded by the National Science Foundation (NSF) to conduct research
called Modeling of manufactured housing production and material utilization. As a part
of this project, two masters theses have emerged (Senghore, 2001; Hammad, 2001). In
both, production process models of construction of a manufactured house were described
and simulation-based tools are utilized to streamline the production process and test

“what if” scenarios. Below is a summary of both the theses.

37

The first thesis was written by Ayman Abdullah Abu Hammad, of the Civil and
Environmental Engineering Department, University of Cincinnati, and was titled
Simulation Modeling For Manufactured Processes In. Construction (Hammad, 2001 ).
This dissertation identified ways of improving the productivity of the manufacturing
process in a housing factory that would lead to a more cost-efi‘ective and efficient system,
utilizing the following procedure: First, the entire factory plan was mapped. Then a
computer-based simulation model for the manufactured housing production process was
developed using Arena software, and finally the model was verified and validated with
real performance measures in the factory. Hammad documented and simulated the

complete production process of a manufactured home in a factory at a macro level.

The second thesis prepared by Omar Senghore, (Senghore 2001), at Michigan
State University, was titled The Production and Material F low Process Model for
Manufactured Housing. This report is also a contribution to the improvement of the
production process of manufactured housing. The overall, goal of the report is to show
how the production process of manufactured housing can be improved and resource
utilization streamlined. To achieve this goal, the following Objectives were identified.
First, process flow diagrams were developed for multi-section’ manufactured housing
production, and then production and material flow process models were developed.
Finally, three-four stations were selected and the process model was transformed into a
simulation model in EZSTROBE (Martinez, 1998). The simulation model for example,

suggested that the productivity at the roofing station was less that at to other stations.

38

“What if” scenarios were developed, and a solution to the poor productivity was provided
by adding specific numbers Of resources. Though, Senghore describes the complete
production process in detail using the flow charts, he finally selected few of the major

stations on the production line and prepared, ran, and validated the simulation model.

2.3 FACILITIES PLANNING AND DESIGN

The proposed research work deals with developing a layout for a manufactured
housing production plant. The tools and techniques that have been used to develop the
layout have been adapted from the field of industrial engineering. This section
summarizes the terminology and the existing literature related to developing plant

layouts.
2.3.1 TERMINOLOGY

Facilities planning: “how an activity’s tangible fixed assets support achieving the

activities objectives” (Tompkins et al., 1996).
Product analysis: The process of breaking down the product into subassemblies and the

subassemblies to individual parts in order to assist in the development of the production

process (Tompkins et al., 1996).

39

Quantitative measure: Flow can be measured quantitatively in terms of the amount
moved between departments. It includes pieces per hour, moves per day, etc. In facilities
with a large volume of materials, information, or people moving between the departments

this kind of measure is important (Tompkins et al., 1996).

Qualitative measure: Flow can be measured qualitatively based on the designer’s
perception as to the degree of closeness that should exist between departments. It may
range from absolutely necessary that two departments be close to each other to a
preference that the two departments not be close to each other. In facilities having very
little movement of material, information or people, qualitative measure is the basis Of
arrangements of departments. A relationship chart is one of the common ways of

presenting the qualitative measure of flow (Tompkins et al., 1996).

Relationship charts: A qualitative description of the degree of closeness that the analyst
feels should exist between different work centers. Degree of closeness is expressed in
form of values, namely, A=Absolutely important, E=Especially important, I=Irnportant,

O=Ordinary closeness, U=Unimportant, and X=Undesirable (Tompkins et al., 1996).
From-to charts: Quantitative measure that represents flow (flow can be flow of material,
information, or people). Flow can be measured in terms of amount moved between

departments/ stations. The F rom—To chart is a square matrix (Tompkins et al., 1996).

Algorithms: Solution techniques or procedures used to solve a problem (Heragu, 1997).

40

2.3.2 LITERATURE REVIEW

Plam Layout and Materials Handling (Apple, 1963 ), one of the earliest books on
plant layout and design, is presented fi'om an engineering standpoint without becoming
too involved in the technical features of equipment design and construction. Apple
emphasizes the major issues of the coordination between plant layout, materials handling,
methods engineering and production planning and control. One of the major goals of the
book is to take advantage of all the different interrelated techniques so as to develop a
satisfactory and practical layout. Layout design techniques can be used for several
facilities like manufacturing plants, warehouses, ofiices, or other industrial and business

facilities

Facility Layout and Location- An analytical approach (Francis & White, 1994), the
authors suggest that studying of Facility layout and location offers considerable potential
for the application of operations research. A few of the major Objectives of this book are:
0 To provide the facilities analyst with new techniques, approaches, and
philosophies for the solution of facility layout and location problem.
0 To stimulate interest in facility layout and location problems within a wide variety
of academic disciplines.
0 To provide an opportunity for a shift in the emphasis on quantitative and

qualitative aspects of facility layout and location.

41

0 To provide a classification of the rapidly expanding body of literature on facility
layout and location problems and attempt to treat a selected portion of the

literature in a unified manner.

In 1954, the literature available on plant layout was in the form of papers and
articles in periodicals. The book Factory Planning and Plant Layout (Ireson, 1954) was
an attempt to organize the literature available and the author’s own ideas about planning
and design of layouts. The author suggests that the final measure of the effectiveness of a
factory plan lies in the cost of manufacturing the product in the plant, and therefore cost
must be an important measure to be applied in the design procedures. Small and medium
size plants have been used in the design problems. The reason for this, the author
explains is that any complicated product consists of a number of smaller problems of
planning facilities fiom the production of component parts and subassemblies to the final

assembly line. Hence procedures described in this book are simple and direct.

The book Facilities Design (Heragu, 1997) deals with the proper design, layout,
and location of facilities. The author suggests, “ poor facility design can be costly and
may result in poor-quality products, low employee morale, and customer
dissatisfaction ” (Heragu, 1997). Heragu provides information on types of layout
problems, traditional approaches to layout design, tools and techniques for layout design,
generic modeling tools, algorithms and group technology. Basic and advanced models are

also available for plant location problems.

42

Facilities Planning (Tompkins et al., 1996), has been and is being used as a
textbook for facilities design in several Industrial Engineering schools in the country. The
book is divided into five parts. Part one focuses on the determination of the requirements
for people, equipment, space, and material in the facility. Part two presents concepts and
techniques to facilitate the generation of alternative facility plans. Part three continues the
focus on producing alternatives but focuses on the functions of the organization. Part four
presents a variety of quantitative approaches that can be used to model specific aspects of
facilities planning. Part five concludes the treatment of facility planning and deals with

evaluating, selecting, preparing, presenting, and maintaining the facility layouts.

.Layout Design and Analysis Software (Sly et al., 1996) is the third part of a three part
series published in [IE Solutions. This paper discusses issues related to facilities layout
and design that software needs to consider in order to produce layouts of high efficiency
and exceptional quality. The issues that need to be addressed by factory layout software
include physical, organizational, and capacity transformations. Basic design skeletons
like that of Reed (1967), Muther (1973) and Apple (1963) are also described. The paper
goes on to suggest the interactive computer-aided relationships and flow-based layout
design techniques like relationship charts, diagramming, flow diagramming, and flow
paths (1996). Finally, Sly et a1. explains the classification of layout algorithms in terms of
mathematical procedures, heuristics, probabilistic approaches and graph theory (1996).
The authors argues that “a good layout well suited to the manufacturing philosophy is the
fundamental starting point for total production system design, and provides a solid

foundation on which to build dynamic simulation studies should they be appropriate. ”

(Sly et al., 1996) Also, with the layouts produced by the software solutions available can

reduce material flow, WIP, and throughput times.

2.4 SUMMARY

In this chapter, a detailed literature review and the terminology used in manufactured
housing and facilities planning and design have been provided. The area of manufactured
housing was further subdivided into the manufactured housing industry and the

manufactured housing product and process details.

44

CHAPTER THREE
TECHNIQUES AND TOOLS FOR PRODUCTION PLANT

LAYOUT DESIGN

45

3.1 INTRODUCTION

The facilities design of a manufactured housing production plant requires input
from the field of industrial engineering. In this chapter, the author has made an attempt to
summarize the different general and specific techniques used for process of design of
manufacturing facilities. In addition, different tools used for presenting and developing

the design layout have been discussed.
3.2 TECHNIQUES USED FOR MANUFACTURING FACILITIES DESIGN

The techniques used in facilities design come from the larger domain of
manufacturing facilities planning, and therefore it is important to understand the concepts
in this area first. Facilities planning, in general can be defined as “how an activity’s
tangible fixed assets best support achieving the activities Objectives”(Tompkins et al.,
1996). In the specific case of manufacturing facilities planning, the above definition can
be modified into the “determination of how a manufacturing facility best supports

production” (Tompkins et al., 1996).

In the US, approximately 8% of the gross national product is spent on new
facilities, with about 3.2 % spent on manufacturing facilities specifically. Over 250
billion dollars are spent on the planning and replanning of facilities. (Tompkins et al.,
1996). There is a significant opportunity to improve the planning and design process of

the production plants. If effective facilities planning processes were applied to

manufacturing plants, then the annual manufacturing productivity in the US. would
increase approximately three times more than it has in any of the last fifteen years

(Tompkins et al., 1996).
3.2.1 THE MANUFACTURING FACILITIES PLANNING PROCESS

The field of manufacturing facilities planning can be subdivided into plant
location, and plant design. Plant location refers to the placement with respect to the
customers, suppliers, and other facilities in the supply chain. As shown in Figure 3.1,
plant design is further subdivided into plant facility system, plant layout, and material
handling. Plant facility system consists of the structure, atmosphere, enclosure, lighting,

electric, communication, life safety, and sanitation related systems.

Plant location
Plant facility system
Manufacturing
Facilities planning /

Plant design Plant layout design

Material handling

Figure 3.1: Subdivisions of Facilities planning for a manufacturing plant facility
(Tompkins et al., 1996)

Layout design consists of production areas, production-related areas (support
areas), and personnel areas within the plant. With manufactured housing production plant
layout Specifically, the layout design consists Of the production line, the major assembly

stations, subassembly stations, feeder stations, storage areas, and personnel areas, like

47

rest rooms, first-aid rooms, tool rooms and lunchrooms. Finally, material handling
includes handling of material, personnel, equipment and information.
In this thesis the production plant and assembly line related areas have been

addressed and emphasized.
3.2.2 OBJECTIVES OF PLANT LAYOUT

Plant layout is the result of integration of several components, like product design,
process design, and schedule design. According to Apple (1963), plant layout can be
defined as .

“Planning and integrating the paths of the component parts of a product to obtain the
most effective and economical interrelationship between men; equipment; and the
movement of materials from receiving, through fabrication, to the shipment of the

finished product. ” (Apple, 1963)

Apple (1963) defines the objectives of plant layout as:

o Facilitates manufacturing process: The layout should be designed such that the
manufacturing process can be carried out in an efficient way. This objective can be
attained by (a) arranging machines, material, and work areas so that material moves
smoothly, (b) eliminating all delays possible, (0) planning flow so that work passing

can be easily identified, and (d) planning for maintenance of conditions.

48

o Minimizes material handing: In a good layout, material handling can be reduced to a
minimum by using mechanical equipment and by the parts continually being in transit
and moving towards the shipping area.

0 Maintains flexibility of arrangement and operation: The layout design Should be
flexible enough to incorporate space for any defective material found and Should be
able to rectify problems.

0 Maintains a high turnover of WIP: If the in-process storage of material is reduced, the
over-all material turnover time is also reduced, thereby decreasing the working
capital.

0 Holds down investment in equipment: In a good layout with a proper arrangement of
machines and departments, the number of pieces of equipment used can be reduced.

0 Makes economical use of floor area: Only if each sq.ft. of floor area in a plant is used
to attain maximum advantage, the layout would be good.

0 Promotes effective utilization of manpower: Proper layout can increase the effective
utilization of labor.

0 Provides for employee satisfaction: This Objective can be met only if attention is
given to items like light, heat, ventilation, safety, removal of moisture, dust, dirt etc.
In this thesis, the issue of space requirements in a manufactured housing production

plant will be studied. Also, an attempt will be made to design a layout based on the

interrelationships between departments.

49

3.2.3 TRADITIONAL APPROACHES TO LAYOUT PROCEDURES

Over the years, several new layout procedures have evolved to assist the planner
in designing layouts. Described below are some original approaches to layout problems.
The concepts used in these approaches are still the backbone for many approaches

presented today (Tompkins et a]. 1996).

3. 2. 3.] APPLE 'S PLANT [A YOUT PROCEDURE
Apple (1977) proposed the following steps in producing a plant layout:

1. Procure the basic data

2. Analyze the basic data

3. Design the productive process

4. Plan the material flow patterns

5. Consider the general material handling plan

6. Calculate equipment requirements

7. Plan individual workstations

8. Select specific material handling equipment

9. Coordinate groups of related operations

10. Design activity interrelationships

11. Determine storage requirements

12. Plan service and auxiliary activities

13. Determine space requirements

14. Allocate activities to total space

50

15. Consider building types

16. Construct master layout

17. Evaluate, adjust, and check the layout with appropriate persons

18. Obtain approvals

19. Install the layout

20. Follow up on implementation of the layout

Apple (1977) also specifies that no two projects are the same and hence the

procedures for designing them are also different. Therefore, the steps described above

need not take place in the specified order. They might change based on the layout design

problem that is being addressed.

3.2.3.2 REED ’S LAYOUT PROCEDURE

Reed (1967) recommended the following systematic plan as steps in planning and

preparing layouts.

l.

2.

Analyze the product or products to be produced

Determine the process required to manufacture the product

. Prepare layout planning charts

Determine workstations

Analyze storage area requirements
Establish minimum aisle widths
Establish office requirements

Consider personnel facilities and services

51

9. Survey the plant

10. Provide for future expansion

3.2.3.3 SYSTEMATIC IAYOUT PLANNING (Muther, 1973)

Richard Muther (1973) formulated a high-level approach to the entire process of
plant layout design. The method developed, is called Systematic Layout Planning (SLP)
and outlines the sequence of steps that should be followed while designing a plant layout.
Figure 3.2 depicts Systematic Layout Planning (SLP) procedure in a flowchart format.
Most of the present day layout design tools use Systematic Layout Planning techniques
developed by Muther, in their tools.

a Quantify the flow of material between departments

0 Create an activity relationship chart

0 Create a relationship diagram

0 Determine the space requirements

0 Create a space relationship chart

0 Create alternate layouts
3. 2. 3. 4 ALGORITHIMIC APPROA CHES

The placements of departments on the basis of their “closeness ratings” or “material
flow intensities” is an issue that has been developed into algorithmic process approaches.
The following the methods are available (Tompkins et al., 1996):

1. Relationship diagramming
2. Pairwise exchange methods

3. Graph-based construction methods

52

 

 

Input data and activities

 

 

 

 

l

l

l

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Flow of 2. Activity
materials relationships
3. Relationship
diagram
4. Space f 5- Space
requirements ___, l ‘__ available
6. Space
relationship
diagram
7.Modifying 8. Practical.
considerations ‘ ’ i ‘— ‘ limitations
9. Develop
layout
alternatives

 

 

 

y

10. Evaluation

 

 

 

 

 

Figure 3.2: systematic layout planning (SLP) procedure
(Muther, 1973) -

The relationship diagramming algorithmic approach is a well known model that
has been used to design a number of plants. It is a variation of Systematic Layout
Planning (SLP; Muther, 1973) and the method developed by Reed (1967). Relationship
diagramming will be further studied and utilized in the thesis. The pairwise exchange
method is based on the travel chart method developed by Reed (1967) and the CRAFT

procedure (which is discussed in detail in this chapter). The graph-based construction

53

method is purely based on graph theory. Graph theory methods are mathematical tools
with conceptual similarities to the SLP method. The graph based construction method

uses both planner and dual plane graphs to compare the layout alternatives.

3.2.4 TYPES OF LAYOUT PROBLEMS

Layout problems arise both in manufacturing facilities but also in service-based
facilities. These problems may occur both in the case of design of new facilities and in
the case of expansion or modification of existing facilities. In general, the layout
problems can be classified into four major categories (Heragu, 1997):
0 Service system layout problem
0 Manufacturing layout problem
0 Warehouse layout problem
e Nontraditional layout problem
“Service system layout problem” refers to layout problems in facilities like restaurants,
offices, hospitals, airports, etc. For example, while designing an ofiice space, the planner
needs to consider issues like the available space, the location, the company’s image,
flexibility, etc. The general layout structures in service facility can be (a) closed structure,
(b) semi-closed structure, (c) open structure and (d) semi-open structure.
“Manufacturing layout problem” refers to the design, expansion, and modification of
manufacturing systems. The major concerns while designing manufacturing layouts are
minimizing material handling costs and providing a safe environment for employees. A
manufacturing facility, not only includes workstations and machines but also rest rooms,

inspection stations, tool rooms, etc.

54

“Warehouse layout problem” refers to the requirement to use the available storage space
efi‘ectively so as to minimize the cost involved in storage and material handling. The
planner needs to consider factors like shape and size of warehouse, height, location, and
orientation of the warehouse.

“Nontraditional layout problem” refers to those types of layout problems that have not
been discussed above. For example the design of the layout for keys on the keyboard or
the layout for the arrangement of CPU, keyboard, monitor, and mouse (and their wiring)
in such a way that they utilize minimum space. These types of problems are termed as

“nontraditional layout problems”.

3.2.5 TYPES OF LAYOUTS

A facilities planner needs to decide the type of layout that best suits the product
being manufactured. Described below are the major types of layouts (Palekar, 1998) and
(Heragu, 1997).
Static/fixed layout: These are used when the product to be made is large and bulky. In
such cases, the product is manufactured or assembled at a fixed location and machinery is
moved around the product as needed. Examples: aircraft manufacture, ship building
yards, etc.
Product or Production Line Layout: These are used when a single or a closely-related set
of products are manufactured in high volume. Machines/workstations are arranged in a
manufacturing/assembly line. The order of machines in the line follows the order in

which processing is to be performed.

Group or Cellular Layout: These are used when a family of components is to be
manufactured by a small manufacturing cell. In this arrangement, a cluster of machines
forms a cell. Each cell has its own material handling system, typically a robot or a

conveyor system.

Process Layout: These layouts group machines that perform similar activities into
processing departments. Thus, in a plant with a process layout, there may be a turning
department (all lathes), a milling department, a grinding department, etc. Process layouts

are common in older plants and in job-shops.

Hybrid Layout: Not all the manufacturing facilities can adopt one of the layout types
described above. Hence, they use a combination of the above layouts; such types of

layouts are called as hybrid layouts.

3.2.6 TYPES OF FLOW PATTERNS

Depending upon the product being manufactured and the production process
being used, a variety of flow patterns can be utilized in layout design. Product flow can
be considered within workstations and departments and between departments, where
individual/single stations are called as workstations and group pf workstations and called

as a department. Described below are these product flow options (Tompkins et al., 1996):
Flow within workstations: can be established based on motion studies and ergonomic

considerations. The flow within workstations should be simultaneous, symmetrical,

natural, rhythmical, and habitual.

56

Flow within depamnents: depends on the type of departments involved. For example, in
a product family department, the flow follows the product. Some of the major flow
patterns followed are depicted in Figure 3.3. End-to-end, back-to-back, and odd angle
flow patterns are used in product departments where one operator works at each
workstation, whereas a fi'ont-to-front flow pattern is used when one operator works on
two workstations, and a circular flow pattern is used when one operator works on two or
more workstations. In a process department, little flow occurs between departments, it
mainly occurs between aisles and workstations. Figure 3.4 illustrates the different flow
patterns within process departments.
F low between departments: is a factor that is used to assess the overall flow within the
facility. Typically, the flow patterns consist of a combination of the few general flow
patterns shown in Figure 3.5. Depending on the application and available space the
machines may be placed in one of the patterns described:
0 The straight line and L flow patterns are used when the production process is
short and simple in nature and contains few or no common components or

production equipment.

57

Flow Patterns

—>
:I [:1 . .
O 0
End to end

Back to back F mm to front

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

h‘ ’
—' .
0 o =
l I '
v’ . '
Odd angle
Circular
Figure 3.3 Flow within product departments
(Tompkim et al. 1996).
[:3 I:
O O . .
‘__> O O
Aisle
Aisle ‘ Aisle
Parallel Pierpendicular Diagoml
Figure 3.4: Flow within process departments
(Tompkins etaL 1996).
‘—__J.
Straight line ‘__.
U-Shaped 5-8mm

W-Shaped
Figure 3.5: General flow patterns
(Tompkins et al., 1996).

58

o The U flow pattern is used when it is necessary to keep both receiving and
shipping ends of the line at the same end of the plant. The pattern is also useful
when there is a material-handling consideration or external-access consideration.

0 The 0 flow pattern is used in machine cells that are serviced by a common
material-handling robot.

0 Serpentine patterns are used for long assembly processes that have to fit in a
square area. Such layouts are also called S type layout pattern.

Straight-line flow and L-flow are the other most commonly used flow patterns.

Examples of flow within a facility based on entry and exit restrictions are shown in
Figure 3.6.

Certain literature also discusses a combination-type flow pattern the dendrite pattern
(Heragu, 1997). This pattern is suitable for assembly operations. In this pattern, the
subassembly lines are arranged in such a way that they feed the main assembly line
directly. In Figure 3.7, the vertical lines represent the subassembly lines and the
horizontal lines represent the main assembly line. When the subassembly lines feed the

main assembly line from both sides, the pattern is called as spine arrangement.

59

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

L a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

j
At the same location
i
1 .
[7 j
7— On adjacent sides v
‘I _.

 

 

 

 

 

 

 

 

 

 

[

 

 

Onhesamesidebutatoppositeends

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

On opposite sides

Figure 3.6: Flow within a facility considering the locations of the entrance and exit

(Tompkins et al., 1996)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L—H

 

 

 

 

 

 

 

 

Figure 3.7: Dendeite flow pattern
(Heragu, 1997)

60

3.3 SPECIFIC TECHNIQUES
This part of the document focuses on the specific layout design techniques that
will be utilized in this thesis. The author has made an attempt to provide examples

whenever possible to make the text easy to follow for the readers.

3.3.1 SPACE REQUIREMENTS
The space requirements are one of the most difficult determinations in facilities

planning. Tremendous uncertainty exists concerning the impact of technology, demand
levels, product mix, etc. In manufacturing environments, space requirements should be
determined first for individual workstations and then for department requirements must
be determined (as each department is a collection of workstations) (Tompkins et al.,
1996)
3. 3. 3. l Workstation Specification

A workstation includes space for equipment, material and personnel (Tompkins et al.
1996)

o The equipment space for a workstation consists of space for the equipment,
machine travel, maintenance, and plant services.

0 The material area in a workstation covers receiving and storing material, in-
process material, storing and shipping material, storing and shipping scrap and
finally, tools, fixtures, jigs, and maintenance material

0 The personnel area for a workstation includes space for the operators, material

handling and operator ingress and egress

61

A facilities planner needs to take into consideration the above space requirements when

designing a production plant.

3. 3. 1. 2 Department Specifications

Once space requirements for the individual workstations have been identified, it is
easy to determine the space requirements for each departments. It is the sum of the
individual workstations involved in that department and the common department service
requirements. The department service requirements include common tools, spare parts,

housekeeping items, information-communication boards etc.

3.3.1.3 Aisle Arrangement

Aisles are provided within the facility to facilitate effective flow. Planning Too-
narrow aisle may result in congested facilities, whereas aisles that are too wide, result in
wasted space. Therefore aisle width should be designed considering the type and volume

of flow to be handled. Table 3.1 shows the different aisle allowance estimates.

 

 

Ifthe largest load is Aisle allowance percentage is“
Less than 6 it? 5-10

Between 6 and 12 it2 10-20

Between 12 and 18 11’ 20-30

Greater than 18ft2 - 30-40

 

 

 

 

*Expressed as a percentage of the net area required for equipment, material, and personnel.

Table 3.1: Aisle allowance estimates
(Tompkins et al., 1996)

62

3.3.2 RELATIONSHIP CHARTS

Flow among the department is a major factor that influences the arrangement of
departments within a facility. Flow can be specified in two ways (Tompkins et al., 1996):
Quantitative measure: Flow can be measured quantitatively, in terms of amount moved
between departments. It includes pieces per hour, moves per day, etc. In facilities having
large volumes of materials, information, or people moving between departments, this
kind of measure is important.
The chart that is used to represent this type of measurement is a From-To chart.

Steps used to construct a From-To chart (Tompkins et al., 1996):

0 Following the overall flow pattern, list all departments down the first row and
across the top column. I

0 Establish a measure of flow for the facility that indicates equivalent flow
volumes. If items vary in size, weight, value, etc., then items may be established
so that the quantities recorded represent the appropriate relationships among the
volume of movement.

0 Based on the flow path for the items to be moved, establish the measure of flow
volumes in the From-To charts. '

Figure 3.8 shows a basic From-To chart depicting the major clusters in a manufactured

housing production plant. The values represent the distance between the clusters.

63

 

= S 8 8
m m .3 .9. a g
a, .5 .§ § § '5, a
.. é ‘3 E" .52 =3 .‘5 e E.”
"" o ‘- 2 ‘H o '5'; C .9 a.
as. 8 a 8 a E g a E
“ a E: 3 M LU 2.- H on U)
Receiving station - S 8 12 15 17 20
Floor stations 5 - 3 7 10 12 15
Walls stations 8 3 -
Roofing station
Exterior finishes stations
Interior finishes stations
Shipping station

 

Figure 3.8: From-To Chart

(Modified from: Tompkins et al., 1996)

Qualitative measure: Space relationship between two departments may range from

absolutely necessity that the two stations be close to each other to a preference that the

two departments not be close to each other. In facilities having very little movement of

material, information, or people, qualitative measure is the basis of arrangements of

departments. A relationship chart is one of the common ways of presenting the qualitative

measure of flow. It describes qualitatively the degree of closeness that should exist

between various workstations (Sule, 1988).

Following are the steps used in creating a relationship chart (Tompkins et al., 1996):

0 List all the station on the relationship chart.

0 Conduct interviews and surveys with persons from each station listed and with the
management responsible for all departments.

0 Define the criteria for assigning closeness relationships and itemize and record
criteria used as reasons for relationship values on the relationship chart.

0 Establish relationship values and the reason for the values for all pairs of department.

0 Allow everyone having input to the development of the relationship chart to have an
opportunity to evaluate and discuss changes in the chart. Figure 3.9 shows a basic
relationship chart presenting the different clusters in a manufactured housing

production plant.

 

 

 

 

 

 

 

 

 

 

Reasons

Highsequenoe
1| 1' . .
Lowproxim'ty
Notrelated
Sarreequiprmrt
Sarmlabor

 

 

 

 

 

 

 

 

 

 

QM-BUJNt-I

 

(Jamming Reasonbehindclosenessvalue

Figure 3.9: Relationship chart
(Tonpkins et al., 1996)

65

3.4 TOOLS FOR DEVELOPING LAYOUTS

Several computer application-based tools can be used for the purpose of
developing layout design. In this section, major attention has been focused on
understanding computer based layout development tools. Though the computer based
layout algorithm can significantly enhance the quality of the final layout by generating
and numerically evaluating a number of layout alternatives, it cannot replace human
judgment. However, computer based layouts are very effective in performing “what if”
analyses. As most of the algorithms are an outgrowth of industry research, very few of
the layout software programs have a commercial version available, though most of the
layout-related software in the market is either usefiil as a presentation tools or as

evaluation tools (Tompkins et al., 1996).

3.4.1 ALGORITHM CLASSIFICATION

The layout algorithms can be classified in a number of ways. An algorithm can be
defined as a technique or procedure used to solve a problem, in this case a layout design
problem. Based on Tompkins et al. (1996), a few of the major classifications are

presented in this section.

3.4.1.1 Based on We of input data required:

Most layouts can be classified based on the type of data required. Some
algorithms require qualitative flow data like relationship charts, while others work with
quantitative flow matrixes expressed as F rom-To chart. Some algorithms, such as

BLOCPLAN, accept both forms of data.

3.4.1.2 Based on theiobjective function:
Two major objectives by which algorithms can be classified are
(a) Minimizing the sum of flows times distances (also called a distance-based
objective): this objective is applicable to data in the form of from-to charts.
Consider the following example:
The objective is to minimize the cost per unit time for movement among the
department. This objective can be mathematically expressed in the form of the

following equation (Tompkins et al., 1996):

m rn
MinZ=Z Z fijCijdij
i=1 j=1

Where:
m = number of departments
fij = flow from dept i to dept j.
or = cost of moving a unit load one distance unit fi'om dept i to dept j.

dij = distance from dept i to dept j.

(b) Maximizing the adjacency score: this objective is applicable to data in the form of
relationship charts. Consider the following example:
The objective of this adjacency score based example is to maximize the adjacency
score. This objective can be mathematically expressed in the form of the

following equation (Tompkins et al., 1996):

mm

Max Z = Z Zfijxy

i=1 j=1

67

The adjacency score can be computed as the sum of all the flow values (or

relationship values) between the departments that are adjacent in the layout.

X] = 1 if departments i and j are adjacent (share a border) in the layout. X.) = 0 if

the departments i and j are non-adjacent.

3.4.1.3 Based on format used for layout representation:

Most layout algorithms use discrete representations. In this form of
representation, the computer stores and manipulates the layout as a matrix (Figure 3.10).
The area of each department is rounded off to the nearest integer in the grids. The other
form of representation is a continuous representation, where there is no underlying grid
(Figure 3.11). Though this representation is theoretically more flexible, it is difficult to

implement on the computer.

Department shapes play an important role in layout algorithms. A department
represents the smallest indivisible entity in layout planning, and a layout algorithm must
not split a department. If any department is too big in size, the planner should lock at the
how the department was defined and, if required, change one big department into two
smaller ones. Consider the following examples (Figure 3.12) of discrete representation.
Departments are considered adjacent if they share a border of positive length. Figures 3a
and 3b are representations of split departments, whereas Figures 3c and 3d are examples
of unsplit departments. For facilities layout purpose the layout in Figure 3e is considered

not practical, as it has an enclosed void in the center of the layout.

68

   

3.10: Discrete representation 3.11: Continuous representation
(Tompkins et al, 1996) (Tompkins et al, 1996)

 

 

 

 

 

 

 

 

 

 

 

 

 

3a

 

 

 

 

 

 

 

 

 

 

 

3d 3e
3.12: Split and unsplit departments
(Tompkins et al, 1996)

69

In cases where the planner wishes to create an irregularly shaped layout or has to
incorporate non assembly line related objects like stairs, offices, or plant services, then

he/ she can create a dummy department.

3.4.1.4 Based on the primary function of the layout:

Finally, algorithms can be classified on the basis-of the primary function of the
algorithm, e.g. (a) layout-improvement type algorithm, and (b) layout-construction type
algorithms.

An improvement-type algorithm starts with an initial layout, and improvement on the
objective function through incremental changes. A construction type algorithm is
developed from scratch. The construction-type algorithm can be further subdivided into
algorithms that assume that building dimensions are provided and those that do not.

In the following section, a few of the major computer-based algorithms are described.

First, few of the major layout-improvement type algorithms will be discussed.

3.4.2 CRAFT

CRAFT, which stands for Computerized Relative Allocation of Facilities
Technique, was first introduced by Armour and Buffa in 1963 and by Buffa, Armour and
Vollmann in 1964. CRAFT, which is an improvement-type algorithm, uses From-To
charts as the input data for the measuring flow. CRAFT first calculates the rectilinear
distance between pairs of department centroids on the initial layout and stores the value

as a distance matrix. The initial layout cost is determined by multiplying each entry in the

70

from-to chart with the corresponding entries in the unit cost matrix (e. g. Cij values) and
the distance matrix.

Then CRAFT considers all the possible two-way or three-way department
exchanges and identifies the best exchange (the one with the least cost). After identifying
of the best exchange, CRAFT updates the layout and computes new department centroids
and the new layout cost, completing the first iteration. The next iteration starts by the
identification of best exchanges in the updated layout. This process continues until no
reduction in layout cost can be obtained. The final layout thus obtained is also called two-
opt (three-opt) layout as no exchanges can further reduce the layout cost. Departments are
not restricted to rectangular shapes. Sometimes this feature causes a layout that is not
very practical in nature. Also it hampers the ability to have long and continuous aisles

(Tompkins et al .,1996).

3.4.3 ALDEP and CORELAP

ALDEP and CORELAP are both construction-type algorithms. The form of data
input is qualitative in nature and is given in the form of a relationship charts. Although
these two algorithms are no longer supported commercially, they are important in

understanding the evolution of computer-aided layout algorithms.

ALDEP, or Automated Layout Design Program, begins by selecting a department
at random. It then continues by choosing a second department with an 'A' relationship
with the department previously selected. It continues through all departments with ties

being broken randomly. The idea is to progressively build around strong relationships.

71

The placement of departments begins by placing the first department in the upper
left corner of a predefined border of the complete facility. The width of the downward
extension is input by the designer and is called sweep width. Each of the following
departments begins where the previous department ends, and the departments are
arranged in a serpentine pattern. After the layouts are prepared, each of the layouts is
evaluated. ALDEP rates by assigning values to the relationships among the adjacent
departments. Each of the relationship codes (A, E, I, O, U, X) has a preassigned value.
ALDEP produces many layouts, rates each one, and leaves the final selection of the

layout to the designer (Tompkins et al., 1996).

CORELAP, which is also a construction-type algorithm, stands for COmputerized
RElationship LAyout Planning. Like ALDEP, it uses qualitative data for construction of
layouts. It constructs a layout by evaluating the total closeness rating (TCR) for each
department. TCR is the sum of the values allocated using the relationship codes (A=6,
E=5, I=4, O=3, U=2, X=l) between the departments. The department with the highest
TCR rating is placed in the center of the layout. The department with the next highest
TCR rating that has an A relationship with the first department is placed on the layout
next. Once the final layout has been prepared CORELAP evaluates the layout by
calculating the layout score which is the sum of the numerical closeness ratings over all

departments multiplied by the length of the shortest path (Tompkins et al., 1996).

The basic procedural difference between ALDEP and CORELAP is that ALDEP

breaks ties between departments randomly while CORELAP uses TCR, or Total

72

Closeness Rating. After the final CORELAP layout has been prepared, a score is found
for that particular layout using the shortest rectilinear path between departments. One of
the problems with CORELAP is that the shortest rectilinear path between departments

may not always be a realistic measure (Tompkins et al., 1996).

3.4.4 BLOCPLAN

BLOCPLAN, which was developed by Donaghey and Pire, at the Industrial
Engineering Department, University of Huston, accepts data input fiom both From-To
charts and Relationship charts, i.e. both quantitative and qualitative data are accepted. It
is a part of the MHAND package (Material Handling and Facility Location models). This
algorithm can be used as both an improvement and construction type algorithm. The
major purpose of BLOCPLAN is to generate and evaluate block type layouts in response
to the user supplied data. BLOCPLAN also uses the relationship codes specified by
Muther in Systematic Layout Planning (1973). BLOCPLAN provides an. empty
relationship chart and the user is prompted to furnish the codes for each of the department
relationships. To prepare a layout, BLOCPLAN needs the number value of each of the
relationship codes. Both user and program-specified values can be used. BLOCPLAN
provides nine zones for locating departments. This feature can be used when the user has
to fix certain departments, either due to entry/ exit restrictions or due to preplanned
positioning of departments.

To evaluate the rel-dist score, BLOCPLAN calculates the sums of the products of
the distances between each pair of departments and the corresponding relationship score.

The lower the rel—dist score, the better the layout. In the case of a distance-based

73

objective/data fi'om the From-To charts is used. The aim is to minimize the sum of the
products of flow, cost and distance. Though it is difficult to capture the initial layout,

BLOCPLAN helps in improving the initial layout (Donaghey, 2000)
3.4.5 AUTOCAD BASED DESIGN TOOLS

AutoCAD is a standard design and drafting package for the creation and
manipulation of 2-D and 3-D line drawings and images. The factory products group at
Engineering Animation, Inc. (EAI) developed software that simplifies designing a new
factory or improving an existing one. The three programs F actoryCAD, FactoryPLAN,
and F actoryFLOW run inside AutoCAD and allow for both qualitative and graphic

analysis as well as provide valuable tools for creating a layout (Owen, 2002).

3. 4. 5. I FactoryCAD

FactoryCAD is an AutoCAD-based tool used to develop new factory layouts and
modify existing ones. It provides all the equipment objects such as racks, cranes, and
conveyors, and design/construction-based elements such as walls, doors, windows,
columns, workcenters, utility lines etc. It is a drafting tool that can be used to develop
virtual model of the factory. FactoryCAD allows for automatic layering, automatic area
and tool clearance hatching, and detailed reporting. FactoryCAD customizes AutoCAD to
automate drawing plant layouts and reporting assets. FactoryCAD menus take the user,
step-by-step, through the drawing process, from drawing double-line walls of any
thickness and creating building grids, to locating individual electrical outlets and gas line

valves (Owen, 2002).

74

3.4.5.2 FactoryPLAN

FactoryPLAN is software that can be used to develop the layout of the factory. It
is a qualitative layout tool and uses the SLP-approach developed by Muther (1973).
FactoryPLAN requires data input in the form of space requirements and activity
relationships. The user can specify the individual department dimensions and the overall
facility shape too. With this data F actoryPLAN creates, manipulates, and scores
qualitative relationship diagrams. These diagrams can be used to prepare various layout
alternatives, and, based on the user’s requirements, the best layout can be chosen.
FactoryPLAN can be used as either an improvement-type layout algorithm or a

construction type layout algorithm (Owen, 2002).

3. 4.5.3 FactoryFLOW
FactoryFLOW is neither a planning tool nor a drafting tool. It is a tool that can be

used to analyze and evaluate a layout, that has already been created.

“FactoryFLOW integrates AutoCAD facility drawings with production routing and
material handling data to compute material travel costs and distances and create product
flow diagrams for graphical flow analysis ” (Owen, 2002).

FactoryFLOW enables the user to examine the effects of changes in routing and handling
methods, from simple changes in lot size to large-scale changes in layout. It helps
improve throughput times and WIP levels by decreasing part-travel distance and the

number of pick-ups and set-downs of the materials (Owen, 2002).

75

Each of these programs addresses individual issues related to layout design. With
the help of these AutoCAD (F actoryCAD, FactoryPLAN, and FactoryFLOW) based

tools, the user can completely develop and present a production plant layout.

3.5 TOOLS FOR PRESENTING LAYOUT DESIGNS

Once the data required for making layout decisions has been acquired, it is used to
determine the positioning of different departments, stations, etc. and then to develop the
layout design. Different tools, such as drawings, templates, three-dimensional physical
models and CAD drawings, can be used to present layouts (Heragu, 1997).

0 Drawings: Drawings have been one of the oldest means of presenting layout
designs. They can be either drawn manually or can be CAD-drawings.

o Templates: Templates by definition are a documents or files having a preset
format, which is used as a starting point for a particular application so that the
format does not have to be recreated each time it is used. Commercial templates
of machines can also be used to create layouts.

0 3D Models: 3D models give a better visual perspective of drawings and
templates. They help analysts in deciding the probable path for material handling
using big equipment.

0 CAD Tools: Computer-aided tools are the most effective tools for both
preparation and presentation of layout design. CAD Tools are easy and efficient
to use and can create both two and three-dimensional drawings. It is also

convenient to edit/change or generate new layouts using CAD tools.

76

3.6 SUMMARY.

In this chapter, the author has made an effort to present major techniques and
tools used for manufacturing facilities planning, design, development and presentation.
The traditional approaches that have been used to develop the current layout techniques
and tools have also been discussed. The specific techniques, which will be used in this
thesis, were discussed. Finally, the possible specific layout design tools that will be used

for the purpose of this research were described.

77

CHAPTER FOUR
MANUFACTURED HOUSING

PROUDCTION PROCESS AND PLANT LAYOUT
DESIGN

78

4.1 INTRODUCTION

In Chapter 3, major techniques and tools used for facilities planning and
design were discussed. Also, the specific techniques that will be used for space and
proximity data collection in this study were described. This chapter attempts to
document the manufactured housing production process and present the data collected
from the two factories in Northern Indiana. Then, appropriate layout design software
programs will be explained in detail. The space and proximity related data collected
from the two factories will then be input in the software program selected
(FactoryPLAN), and the different layout alternatives will be generated. Finally, these

layout alternatives will be evaluated on the basis of effectiveness scores obtained.

4.2 MANUFACTURED HOUSING PRODUCTION PROCESS

In order to understand the production process, one needs to understand the
product that is to be manufactured. The manufactured home, as described in Chapter
Two, is a home on a permanent chassis built in a controlled factory environment and
is designed to be used with or without a permanent foundation. Depending upon the
requirements of the homebuyer, the manufacturer can provide either a single-section

or a multi-section manufactured house.

Two manufactured housing production plants were studied in order to better
understand the general production process of a manufactured home. To maintain the
privacy of these establishments, their names will not be mentioned in this thesis.

After visiting the production managers, and refening to existing research work in this

79

area, the author has developed generic production process details. These details are

described below.

4.2.1 STATION CLASSIFICATION

The assembly line in a manufactured housing production plant consists of -
many different types of stations. Not all the stations on or beside the assembly line in
a production plant are of one standard or particular type. The stations can be
classified into main assembly stations, sub-assembly stations, feeder stations, and
internal and external storage areas, based on the type of activity taking place at that
station/area.

Main assembly stations are the major stations (sometimes referred to as
primary stations) on the assembly line, and the location where sub-assemblies
(components) are installed. The roofing station, for example, is a main assembly
station where the roof truss from a roofing sub-assembly station is installed over the
home.

Sub-assembly stations are secondary stations that fabricate sub-assembly
components for installation at main assembly stations. For example, interior and
exterior walls are first assembled at a sub-assembly station, and then they are installed
at the walls’ main stations.

Feeder stations are stations that provide individual components to the main
assembly stations, i.e., the raw material stored at the feeder station itself is installed

directly. For example, kitchen appliances are stored beside the assembly line near the

80

interior finishes and cleanup main assembly stations, and the appliances are supplied
directly to the interior finishes main activity stations, as and when needed.

Internal or external storage areas are provided, depending upon the inventory
maintained for different kinds of material, weather conditions, the bulk/size of the
material, and the cost of the material. Some of the materials that are stored externally
are chassis, roof shingles, and trusses; whereas material like drywall boards, foam,
and carpets are stored internally.

A greater number of sub-assembly/feeder stations are desirable as they not
only reduce the overall processing time of the product, but they also reduce the
number of operations taking place at main assembly station. Several manufacturers
purchase sub-assemblies from suppliers for certain elements and feed them directly to
either the sub-assembly or the main assembly line. An efiicient assembly line usually
has tasks broken down and divided in such a way that they are carried out with the

minimum possible idle time on main stations (Bemkardt, 1980).

4.2.2 ASSEMBLY CLUSTERS/PRODUCTION PROCESS DETAILS

The production process of a manufactured home consists of step-by-step and
methodical practices of interrelated tasks that are carefiilly coordinated so as to
produce a home. The activities on an assembly line are well planned to ensure
continuous production.

The different activities on the assembly line can be grouped into
clusters/departments depending upon the element that is being built. The major

clusters in a manufactured housing production plant are:

81

0 The floor cluster

0 The walls cluster

0 The roof cluster

0 The exterior finishes cluster

0 The interior finishes cluster (Senghore, 2002)

4. 2. 2. I THE FLOOR CLUSTER

The production process begins with the chassis, or the structural fiame on
which the house is built, being pulled from the external storage area into the factory.
The floor joists are fabricated based on the structural requirements at a sub-assembly
station. Rigid insulation is then installed. Openings are provided in the floor joists to
accommodate the ductwork (HVAC) and piping (plumbing) requirements. This floor
sub-assembly is then placed over the chassis and glued and nailed in place. The
chassis then moves to the next station. The chassis enters the plant on wheels (tires).
These chassis are generally either (a) moved on inflated base plates or (b) moved
longitudinally on tires and laterally on movable metal tracks with track wheels
perpendicular to the direction of the chassis wheels.

At station two, the floor joist is covered with decking. Decking is usually in
the form of 5/8” floorboard. It is glued and nailed in place. The size of these main
activity stations is governed by the size of the home being manufactured. The station
width, in many plants, is designed for the width of a single-section home. If a double-
section home is being manufactured, then two individual single-sections are prepared,

one after the other.

82

 

 

 

 

 

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Figure 4.1: Manufactured Housing Production Process
(Senghore, 2001 )

83

4.2.2.2 THE WALLS CLUSTER

The chassis then moves to station three, where wet and dry (kitchen and toilet)
areas are demarcated. Vinyl sheet rolls are suspended from a metal roll and vinyl
pieces of the correct size are cut and installed in wet areas. The interior
walls/partitions are placed next. The walls are usually fabricated at a sub-assembly
station and then installed in place, on the main assembly station, using a crane. The
sub-assembly also takes place in several steps. First, based on the spacing of the studs
provided on the floor plans, the studs are pasted and screwed to the drywall boards.
Then, depending upon whether or not the walls are to be painted, the major activity at
the next sub-assembly station is spraying paint and drying. Depending on schedule
specification, the interior walls are ready for installation by the time the chassis leaves
the floor cluster. The heavy cabinetry in the kitchen and other big bathroom fixtures,
like sink tops and shower compartments, are also installed at the interior walls main
assembly station. Based on the floor plans of the home being manufactured, the
cabinets are generally prefabricated and ready for installation. The bathroom fixtures
are placed at a feeder station near this main assembly station.
The home then moves to station four, where the exterior walls are installed. Partly
fabricated exterior walls are put in place on the main assembly station. Rigid
insulation is then installed, and the walls are covered with exterior wallboard at the
main assembly station. Rough electrical and plumbing work is also done at this
station. In some plants, both interior walls and exterior walls stations have two main

assembly stations. In this system the major activities are divided into two.

84

Until this point the home usually moves longitudinally, but as it enters the
roofing cluster, the home is moved laterally. One of the reasons for the change in
direction is because of the roofing cluster activities, which in the case of double
section homes require both the single sections to be joined together. Additionally the
shape of the production area is usually rectangular, and the width of the rectangular

space is usually utilized by the previous stations (Figure 4.2).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A
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Figure 4.2: Typical Production Plant Layout

4.2.2.2 THE ROOF CLUSTER

In most production plants, the fabrication of roof trusses is sub-contracted and
tnrsses are supplied fiom a loading dock near the roof assembly station. The roof is
then fabricated using these trusses and other raw material at the roof sub—assembly
station. First, the individual trusses are positioned correctly based on the spacing
specified in the plans, and then the ceiling board is glued at the base of the assembled
truss. At the next sub-assemblystation, the truss is filled with both rigid and loose

insulation, and finally the ceiling boards are taped together and paint is sprayed on

85

them. By the time the home comes to the roof installation station, the roof is dry and
ready to be installed. It is then hoisted by a crane and moved from the roof sub-
assembly station to main assembly station number five and installed over the home.
In the case of a double-section home the two units are joined before installation. The
insulation activity in some plants is also carried out at the main assembly station. The
next step involves the installation of roof sheathing (Oriented Strand Board). The
boards are nailed in place. Installation of shingles is the next major activity in the roof
section. Once the shingles are installed, the home is ready to move to the exterior

finishes section.

4.2.2.4 THE EXTERIOR FINISHES CLUSTER

Some of the exterior finishes activities are carried out simultaneously with the
roofing activities. The first major activity at station six is to cut out the exterior
wallboard for the installation of doors and windows. Doors and windows are supplied
from a feeder station, and the installation of doors and windows involves checking the
spacing, installing of the frame, and finally installing of the door and window units as
specified in the drawings. Finally, the exterior sidings, exterior lamps, and doorbell

are installed.

4.2.2.5 THE INTERIOR FINISHES CLUSTER
By the time the home comes to the interior finishes cluster the two sections of
the double-section home have been separated again. The interior finishes and final

cleanup activities are the last set of activities taking place on the assembly line. This

86

section also involves testing and inspection activities. The final electrical, plumbing,
HVAC, and mechanical work are carried out at station seven. The installation of foam
and carpet happens next. These activities happen at station eight. The toilet is also
installed at this station. The heavy kitchen appliances like the refrigerator and
cooking range are placed at station nine. The home is vacuumed and all cabinets are
cleaned. Finally, the material to be installed in the home after installation on the site
is placed inside the home. All final testing takes place at this station also. Additional
axles and tires are installed for transportation purposes. At station ten, the home is
then covered with white plastic sheets and is pulled out of the plant. It is now ready

for delivery.

The production process described above is a typical production process.
Different manufacturers may have similar process details but more or fewer main

assembly stations or sub—assembly stations, on their production line.

4.3 DATA COLLECTION FOR SPACE REQUIREMENTS AND
RELATIONSHIP CHARTS
Alter understanding the complete production process of a manufactured home,
the author worked on developing data collection formats for space and relationship
charts. The data was collected from two manufactured housing production
establishments. To maintain the privacy of these establishments, they will be referred
to as Production Plant A and Production Plant B in this research work. As explained

in chapter three, in order to prepare design layout alternatives, data related to space

87

and proximity requirements (i.e. relationship charts) is needed. Data was collected

under the following two categories namely:

0 Space Requirements

0 Activity Relationship Charts

4.3.1 SPACE REQUIREMENTS
From the different methods available for data organization, the author decided
to use the table format to order the space requirement data fi'om the two production
plants. In order to have accurate data, the table included specific assembly stations,
. sub-assembly stations, feeder stations, and storage areas for each cluster and related
space areas. Details associated with the type of material (stored, subassembled or
installed) and area specifications were also collected. Table 4.1 shows a space
requirement table for station six in Production Plant A. The space requirements are
shown for the roof installations cluster. The table includes the cluster name, such as
floor, walls, roof, and interior finishes; a description of type of station such as main
assembly station, sub-assembly station, feeder station and storage areas; station area;
the major activities taking place at the station (set roof truss, install insulation); source
of supply of raw material (ceiling board feeder station, paint feeder station); and
finally space requirements. The space requirement tables for all the other stations are
available in Appendix A. Similar space requirements were collected from Production

Plant B and are also provided in Appendix A.

88

Table 4.1: Space Requirements station No: 6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

. material
Cluster . . . Ma La' . . lager Ra 1
Description Frauen Type (l'b) jor activities material pplied
. ain
Roof Irgztfallatron O ssembly 2400
ation
ub- t roof t
ssemhly 1600 sed on russes 0:3:
ation cing
:sbembl 1600 glue 8. nail th iling ceiling board
ation V pairing brds «rs eeder station
ub- pray paint th oof sub-
ssembly 1600 iling adrying ssembly
ation oose insulation ation
4.3.2. RELATIONSHIP CHARTS DEVELOPMENT

The data collected for the relationship charts is a qualitative measure, and

therefore it is different from a quantitative space requirements measure. The

relationship chart development included a series of steps. These steps are described

below:

0 The process began with the development of an empty relationship chart.

Based on the production process information and the station description, all

the stations were positioned in the top row and left column. Each of the

stations was represented with either numerically or alphabetically (Table 4.2).

o This empty relationship chart was then filled based on the production process

information. Each station in the relationship chart is either related or unrelated

to every other station. Based on the relationship between each station pair,

89

different closeness ratings were assigned. This rating could be due to one
station being a direct source of raw material or sub assembled component
supply or due to stations sharing common material, labor, tools, or equipment.
The closeness ratings assigned are based the Systematic Layout Planning

technique developed by Muther (1973) and are shown in Table 4.3

Criteria were defined and the closeness ratings were assigned based on the
criteria. Example: An A relationship (Absolutely necessary closeness rating)
between stations was assigned when the stations had a direct high proximity
(criterion). This criterion is shown in table 4.4. A closeness rating and a

reason were established for each pair of stations in the relationship chart.

Once this chart had been developed, it was discussed with two production
managers at each plant. Their input was established in the form of suggestions

for change of relationships.

If a production manager disagreed with any of the relationships shown on the
chart, based on his/her experience, the author requested him/her to highlight it
and provided an empty relationship chart for the manager to use to fill in the
changes. Table 4.6 shows the relationship chart developed for production

plant A.

90

Table 4.2: Description of all main assembly, sub-assembly and feeder stations

 

NoJAb.

Description of Stations

 

I-Main assembly stations

 

Chassis on wheel and axle pulled into the factory.

 

Place assembled floor frame with insulation, ductwork and wiring over the chassis

 

Placement of interior walls (studs with panel on one side only),

 

Placement of cabinets, toilet compartment, bathtub, kitchen sink.

 

Placement of exterior walls

 

Rough electrical and mechanical, and final exterior walls installation

 

Installation of all electrical and mechanical equipment

 

Roof installation

 

\OWNONUI3WN—

Installation of shingles on the roof and cut outs for doors and windows

 

Exterior wall finishes and installation of side shingles. Installation of door& windows,
and trim

 

ll

Begin interior finishes- install foam for carpeting, complete interior drywall finish

 

12

Install carpet, final electrical and plumbing finishes, install marriage walls.

 

13

Interior Finishing and cleanup, placement of material to be installed at site

 

II-Sub-assembly stations

 

>

Fabrication and storage of ductwork and plumbing, and placement of tires.

 

Assemble floor frarne- place black sheet, place insulation, place floor joist, place wire
and duct work, staple black sheet to the floor joist

 

Sub-assembly of interior walls

 

Assembly of cabinets, kitchen, and toilet sinks

 

Sub-assembly station for roofing main activity stations.

 

Fabrication of roof truss, installation of ceiling board, painting, drying and finishing

 

Q'UI'UUOW

Installation of loose and rigid insulation

 

III-Feeder stations

 

Storage of ductwork and plumbing pipes

 

Storage of cabinets

 

Storage of drywall panels

 

Storage of drywall, doors and windows, and sheathing.

 

Storage of roof shingles

 

"1105-6793

Storage of foam and carpet and drywall (marriage)

 

Storage of wall boards and tools

 

Storage of mirror, and appliances.

 

Storage of drapes and appliances.

 

r—n—ns-‘I

Storage of toilets and materials to be shipped to the site for onsite installation

 

 

"a?

 

 

Storage of drywall panels and wooden members for roof frame fabrication

 

91

Table 4.3: Closeness ratings Table 4.4: Reason/criterion behind
closeness value

alue

 

closeness Unrelated

 

The approach used to develop the relationship chart is described below:

1. All the stations having a direct relationship between each other have been
assigned an “A” relationship. This covers the relationship between sub-

assembly stations/feeder stations directly feeding the main assembly stations.

2. All stations which are not related, have been assigned “U” (unimportant

relationship) and are represented in normal non-bold font.
3. All other relationships assigned in this study between stations are either an “1”

(Important) or “E” (Especially important). These relationships are assigned

due to the reasons shown in Table 4.5.

92

Table 4.5: Reasons for assigning E or 1 relationship between stations

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Stations Reason for relation between stations
having I or E
relationship
Assuming that all electrical installation and plumbing works
1 1 & 6
are related
2 2 & 5 Assuming that all insulation work happen together
3 2 & 8 Assuming that all insulation work happen tggether
4 4 & 6 Assuming that walls need to be aligned with each other
Assuming that all electrical installation and plumbing works
5 5 & 7
are related
6 6 & 9 Direct sequential order will help to avoid rework.
(Alignment between exterior walls and doors & windows)
7 6 & 11 Direct sequential order will help to avoid rework.
(Alignment between marriage walls and exterior walls)
Assuming that all electrical installation and plumbing works
8 7 & 11
are related
Assuming that all drywall paint related actual work and
9 11 & F
rework takes place together
10 11 & In case any wallboard repair has to be done it is identified at
g the interior finish station

 

 

In production plant A, neither production manager X nor production manager
Y disagreed with any relationships. Similarly, in production plant B, both the
production managers agreed with the closeness ratings provided between the stations.
Once the final relationship chart for each production plant was developed, it was used

to prepare layout alternatives.

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94

4.5 PLANT LAYOUT DESIGN WITH AVAILABLE SOFTWARE

After space and proximity related data was collected, there was a need to search
for available software programs for preparing the layout alternatives. Upon reviewing
different options available for plant layout design, the author narrowed down the scope of
the search to two major plant layout design sofiware: BLOCPLAN and FactoryPLAN. In
the following section, each of these software programs is described with the help of an
example. FactoryPLAN was eventually chosen to develop layout options for this research
work. The data collected, including the space requirements and the relationship charts for

production plant A, were input into F actoryPLAN .

4.5.1 BLOCPLAN (Donaghey, 2000)

As described in Chapter Three, BLOCPLAN was developed by Donaghey and
Pire, at the Industrial Engineering Department, University of Houston. Their algorithm
can be used for both the improvement of an existing layout and the construction of new
layout. The major purpose of BLOCPLAN is to generate and evaluate block-type layouts
in response to user supplied data. Described below is the step-by-step procedure used by
this program to generate a layout. (For the convenience of the reader, an example has
been used to explain this procedure better. Data collected in the previous section cannot

be used, due to certain limitations of the software.)

95

4.5.1.1 INTRODUCTION

BLOCPLAN can be used in both DOS format and in Windows format. The
program is installed under the name MHAND (Material Handling and Facility Location
models), of which BLOCPLAN is a part. Alter activating the program, the user is

prompted to enter data.

4.5.1.2 DA TA INPUT

Data of space requirement and relationship chart related data could either be
supplied from the disk (enter D) or the keyboard (enter K). The input from the disk refers
to problems already created and saved in BLOCPLAN. Data can also be entered directly
using the keyboard (in the case of new plant layout development). Once the method of
data entry has been specified, the program prompts the user to supply Department names
and areas.
4.5.1.3 DEPARTTl/flENT NAMES AND AREAS

A maximum of 18 stations can be specified for a single story layout problem. The
user can change this information as and when required. Due to limitations like restricted
number of stations, real time data could not be used, therefore, an example problem is
presented for better understanding. Figure 4.3 presents the list of departments and their

respective areas entered for the example problem.

96

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Figure 4.3: List of department and respective areas in BLOCPLAN
4.5.1.4 REIA TTONSHIP DA TA
BLOCPLAN uses relationship codes specified by Muther (Muther, 1961) in
Systematic Layout Planning for relationship chart development. The user is provided
with an empty relationship chart in order to enter the relationships between the
departments (previously specified). The bottom of the screen displays the relationship
codes (A, E, I, O, U) for user convenience. Figure 4.4 presents the relationship chart

developed for the example problem.

97

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Figure 4.4: Relationship Chart in BLOCPLAN

4.5.1.5 RELATIONSHIP CODES VALUE

Each of the relationship codes used in BLOCPLAN has a default value. The user
can change these codes based on the specific production process details. The default
score for each of the codes is presented in Table 4.7. These scores were used for
development of layouts.

Table 4.7: Default score for the relationship codes

 

 

 

 

 

 

 

CODE SCORES
A 10

E 5

I 2

O 1

U 0

X -10

 

 

 

 

98

Based on the scores assigned, BLOCPLAN sums all the scores for each of the
individual departments and computes individual department scores. The department

scores for the example problem are presented in Figure 4.5.

'; BPBOUD

czrlellgfi '

 

 

Figure 4.5: Department Scores
The user is then prompted to specify the Length/Width ratio of the facility. This
length and width ratio is applicable to the complete facility itself and not to any particular
department. The user can specify one of the Length/Width ratios suggested in Figure 4.6.
In case the user wants to use a Length/Width ratio other than that shown in the figure,

then option 5 can be chosen, and the ratio can be entered manually.

99

SEL. 4

CELECT DESIRED L/N R9110 (l,2,3,4,5) I

 

Figure 4.6: Length/Width Ratio

BLOCPLAN allows the user to include specific product flow information, based
on the different types of products being manufactured. This information can be supplied
by firrnishing a list of products and the departments that they will enter during the
manufacturing process. A maximum of 13 products , can be specified. Though a
manufactured housing production plant produces both single-section homes and multi-
section homes, the method/process of manufacturing is same, i.e. during the production
of either size of manufactured homes, both types of homes use the same stations. No
separate product information needs to be specified. At this point, the user is directed to
the BLOCPLAN main menu, which has six major options. Figure 4.7 shows these
options. Since the manufactured housing production plant layout design problem is a
single story layout problem, option 3 is selected. The single-story layout menu is further

divided into seven major sections (Figure 4.8). Each of these sections is explained below.

100

Manually insert departments: BLOCPLAN provides the user with nine zones
(each zone, again divided into left and right side) in which to manually insert
departments. These zones are designated fi'om A to I and are arranged in three
tiers in three zones. The overall layout for manual insertion depends on the
Length/Width ration previously specified. This option can be used for fixing
. departments either due to entry/exit limitations or due to other structural reasons.
Random layout: This option provides a layout based on the department numbers .
and areas, irrespective of the relationship or product information provided. Based
on the layout generated, a layout score is provided. This score can be computed
by obtaining the adjacency relationships and scores and calculating their total
value. It is then divided by the sum of the positive relationship scores, of
individual stations.

Improvement algorithm: This algorithm operates on a layout that has been
previously saved. It interchanges each pair of departments in the layout, and
scores the layout, and then displays it.

Automatic search: This option starts with an initial random seed layout and
operates on the layout until it is unable to improve it any further. This new
improved layout then becomes the seed layout and attempts are made to improve
upon it by using the pair-wise interchange method. This procedure continues until
no more improvements can be made. The resulting layout can be saved for firture
reference.

Review saved layouts: Layouts that have been previously saved can be reviewed

by using this option.

101

0 Table of saved layouts: This option creates a table of scores of all of the layouts

that are currently saved.

0 Main menu: This option directs the user to the main menu (shown in Figure 4.7).

'3 Bonno

I‘TIIl'r‘ Hal-Eli 1‘11””

F-ll l-iI'HlilTlEJ-‘i'.

r‘iilifllilllif‘.
$1.5I‘.‘l“.—ilil: {El-‘lr‘li
‘IfUllL' EQUIP Lt‘l‘r'r'llf?
lr‘rllH I'l“ fir‘<'.‘l't‘ l.x'r'r“"l'='r.

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,‘.' I l. U 1M Hf)
P1111.- .‘Zr Incl ion 1 IS"J

.IN 11 - ..
lllllIli ‘94.?

 

Figure 4.8: BLOCPLAN single story layout menu

102

One of the layouts generated fi'om the example data using the automatic search
option in the single story layout menu is presented in Figure 4.9. The layout score is 0.70,

with 1 being the best possible score.

IHYOUI SCORE.
8.70

1119 IE
1 ILOORERQHEZ IILEINSI I3 INIHHLLSR‘BHIH
I -EXCHM SE 4 IHSICHBIHEIS

5 urrrrrrurr
emunLLmsr _ , . _ . , .
7 msrroor :3 roommroue rxrsrrrm 114 Exrntcmorrrs
11 nnrnrncrunrr
12 nprrrnrcrrnnnrts _
13 CLEANUP 14 srrrrnunrrrrrnr

 

Figure 4.9: Layout developed in BLOCPLAN
4.5.1.6 SlM/[ARY OF BLOCPLAN .
BLOCPLAN is a layout development tool that can be used for simple layout
design problems. It has limited efi‘ectiveness due to certain limitations, such as the ability
to input only limited number of departments and an inability to accept Length/Width

ratios for individual departments.

The following section describes another layout design software program
available, FactoryPLAN. This software was finally chosen for the purpose of layout

design of a manufactured housing production plant.

103

4.5.2 FACTORYPLAN (EA1, 1999)

As described in chapter 3, FactoryPLAN is an AutoCAD-based tool used for
design and analysis of plant layouts. The design group at Engineering Animation Inc.
(EAI) has developed this tool. It is a qualitative layout design tool, which, like
BLOCPLAN, uses Muther’s Systematic Layout Planning for the design process. In the
following section, the author documents the methods of this program using data gathered
from Production Plant A as a basis for developing Manufactured Housing Production

Plant layout alternatives.

4. 5. 2.1 INTRODUCTION

FactoryPLAN, an AutoCAD-based tool, enables the user to organize the proximity and
flow relationships that should be considered when designing a plant layout. Once
FactoryPLAN has been loaded in AutoCAD, the user needs to specify the factory
drawing parameters (just like specifying parameters for any AutoCAD drawing). Figure
4.10 shows the window that appears for setting these parameters. The user should define
the Drawing units and limits (lower left and upper right corners). FactoryPLAN uses the

default settings for layer and line type settings.

104

 

Figure 4.10: Drawing Parameters in FactoryPLAN

Oncetheusersetsthedrawingparameters,themaindropdownmenubar(Figme4.ll)

Changes fiom

fie Edit flier-r insert Fgrmal Tools grew Jirrregrzr‘r Err-filly Farley [H1396 Eirricrr Belp

5F: grail» luau F1773! 75:15 L131: l‘rrfirzizr L237}; Q'rzrl'lta'a [Hagar 12:27"; its; kg}: _

Figure 4.11: Main menu bar

The major FactoryPLAN functions that are added to the already existing AutoCAD menu

barare:

o Charts/Data: Commands on the Chart/Data Menu allow the user to create and

manipulate data files and relationship charts (Figure 4.12).

105

 

{git Relationship File (FPEDm...
it Space file...

 

insert Relationship Chart..
yiew Relationship Chart

Save Old Chart..
Convert RELto AMX..

 

 

 

   

MiewAll
Draw Relationships...
Men Relationships

_..... a..- a... «HR—VIAA. .___

 

Score...

We}! Results...

Query Relationships

Move Department

Group Workcenter and Border
Stretch

Bedraw

 

Change Color Code...
Make Legend...
Scale Workcenter...
Delete Wort_<center...
Box Workcenter...
Reshape Area

Delete Relationships
Relationship Diagram filter...
Relationship Lines Oil
Relationship Lines Qn

 

 

Figure 4.12:Charts/Data and Diagram from the main menu bar

0 Diagram: Commands on the Diagram Menu manipulate and score a relationship
diagram based on the information obtained from the data located in the

relationship charts (Figure 4.12).

106

Optimize: By using this option, F actoryPLAN generates a design layout. It then

proceeds to optimize this layout based on the number of times the user wishes to

modify the layout. Though this option seems very useful, the author didn’t find it

very effective, as when optimize is used, a new layout is generated and

improvements on an existing layout cannot be performed.

4.5.2.2 DA TA FILES

FactoryPLAN stores space and proximity-related information under different file

names and types, therefore, the user needs to specify the space requirement and

relationship data-related file. FactoryPLAN will provide with valid file extensions for the

files (Table 4.8). The user can create new space and relationship related files here (in

case these files have not been created).

Table 4.8: FactoryPLAN data file

 

 

 

 

 

 

(EA1 1999)
Nos.‘ File Activity
File containing a list of activities and their relationships to
. _ other activities. Three types of relationships can be
Relationship] specified:
1 AMX 0 Proximity (closeness-desired) AEIOUXZ
- Flow ‘
0 Aggregate of proximity and flow
2 Space File containing a list of activity names, their size requirement and their
height/width ratios
s cc . . . . ,
3 8:" d a rd 3 File containing a list of space types and each type 5 layer
and color
‘ Reason Codes File containing a hst of reason codes, which can

 

 

be used to describe the reason for assigning a proximity
relationship

 

107

 

After clicking on the “Edit Relationship File (FPEDIT)” command under the
Charts/data tab in the dropdown menu bar, the user can specify the file names and the
location where these files are stored. Figure 4.13 shows the data files window.

FactoryPLAN provides the user with standard space and reason code files.

 

 

 

 

 

 

 

 

rem“ " " ' ‘ ‘ a
neutronsfimpzm Fae.” |C2\PROGRAM FILEstrocctD 2002\NAMITAxt ]
SPACE Fie... ICAPROGRAH FILESMUTUCAD 2002\NAMITAU |

space STANDARDS no,“ [cxourxsuppomxoemuusrq ' |
Reason Codes... [C:\CIHF\SUPPORT\DEFAULT.REA —_|

 

 

 

l" SortActivinepatment:

-____lw _H_eb_l

 

 

Figure 4.13: FactoryPLAN Data Files
F actoryPLAN prepares and analyzes layouts in the following three steps:
0 Enter activity name and space data.
0 Enter relationship data.

0 Generate and manipulate the layout.

4. 5. 2.2 ACTN/'ITY'DEPAR'IMENTLISTANI) SPA CE INFORM/1 'IYON

After specifying the file names and location of storage, the next step is to enter the
activity stations. The activity stations/department list dialogue box appears immediately
after the FactoryPLAN data files have been specified. As the author is preparing a layout
for a manufactured housing production plant, the dialogue boxes/windows shown below
display the activity stations for production plant A. Figure 4.14 shows the dialogue box

where the abbreviations for the names of the stations (main activity, sub-assembly and

108

feeder stations/storage areas) have been entered. BLDG-OUT is an artificial default
activity created by FactoryPLAN to represent relations of real activities with the outside

of the building.

 

ACTIVITY usr , _ “a ,,---_-_,._
1Q_FINLBLE9N :z‘
BLDG-IN I l

i“ -5. is

2_FLOOR_FRHNE i

3_1m_unLLs1 -*

ri_r-:xr_unLLs1
o_noor=_rrrsr swim ]
s_noor:_srrmst
‘7 noon turn
9 rm FINISH 5.23% l m Help I
n_FnB_FLn_Jsr -
laLos-our v

 

 

 

 

}
i
l
|
r

 

 

 

 

 

Figure 4.14: Activity/Department List
The user can then enter all the activities required. For the purpose of this research, the
activities were divided into three major sections:
0 Main assembly stations depicted in 1_CHAS SIS format
0 Sub-assembly stations depicted in A_FAB_FLR_J ST format and
0 Feeders/Storage stations depicted in SA_DUCT__PIPE format.
A list of all of the abbreviations and the associated station details for the layout design of

Production Plant A is shown in Table 4.9.

109

Table 4.9: Station Descriptions

 

Main assembly stations

 

 

 

 

 

 

 

 

 

 

o bbreviations Station description
1 l_CHASSIS Chassis on wheel and axle pulled into the factory
2_FLOOR_FRAME Place floor frame with insulation, ductwork and wiring over chassis
3 3_INT_WALLSI Placement of interior walls (studs with panel on one side only)
4 B_INT_WALLSZ Placement of cabinets, toilet compartment, bathtub, kitchen sink
5 l4_EXT_WALLSl Placement of exterior walls, roughplumbing and electrical work
6 4_EX'LWALLSZ Installation of exterior walls completed
7 5_ELEC_MECH lation of all electrical and meclmnieal equipment -
8 b_ROOF_INST Roof installation
9 7_DOOR_WIND Installation of doors & windows

 

10 |8_ROOF_SH[NGL

Installation of roof shingles and external finishes (sidLng)

 

Install carpet, final electrical and plumbing finishes, and marriage

 

 

ll 9_INT_FINISI-1 walls.
12 10_FIN_CLEAN interior finishing and cleanup
l3 11_MAT_PLCMNT Placement of material to be installed at site

 

Sub-assembly stations

 

l4

lA_FAB_FLR_JST

Fabrication and storage of ductwork and plumbing, placement of tires,
floor joists

 

15

B_ASM_INT_WAL

Assemble floor frame- place black sheet, place insulation, place floor
joist, wire and duct work, and staple black sheet to the floor joist '

 

16

C_ASM_CABINET

Assembly of cabinets, kitchen, and toilet sinks

 

l7

lD_FAB_RF_TRUS

Sub-assembly station for roofing main activity stations.

 

18

E_CEILBD_INSU

Fabrication of roof truss, installation of ceiling board, paint spraying,
drying, and finishing

 

19

 

F_PA1NT_CE1L

 

Installation of loose and rigid insulation

 

eeder stations

 

20

SA_DUCT_PIPE

Storage of ductwork and plumbing pipes

 

21

SB_CABINET

Storage of cabinets

 

22

SC_DRYWALL

Storage of drywall panels

 

23

SD_DOOR_WIND

Storage of drywall, doors and windows, sheathing

 

24

SE_ROOF_SHING

Storage of roof shingles

 

25

SF_FOAM_CARPT

torage of foam and carpet and drywall (marriage)

 

26

SG_WLBDS_TOOL

Storage for wall boards and tools

 

27

SH_MIROR__FRDG

Storage for mirror, and appliances

 

28

SI__RANGE_DRPS

Storage for drapes and appliances

 

29

SJ_CMD_SHP5MT

Storage of toilets and materials to be shipped to the site for installation

 

30

 

SK_RF_TRS_MBR

 

Storage of drywall panels and wooden members for roof frame

 

 

fabrication

 

110

SPACE INFORMATION/REQUIREMENTS

Once the activity stations have been defined, the user needs to specify the
individual space requirements for each of the stations. The space requirements can be
input by clicking the “Space information” tab in the dialogue box that is shown in Figure
4.14. Figure 4.15 shows the dialogue box that appears for entering the space requirements
data. A list of all the stations is given, but the user must provide the area, type, height and
width of each of the stations. Afier inputting this information for each station the user
should click the update button to make the information available to be accepted by the
software. Afier the space information has been supplied for all the stations, the
information should be saved in the previously specified space file. After clicking on the

save tab, the data will be saved in the location specified in the FactoryPLAN data file

(Figure 4.14)
3P; its rig—.2. C'\.PP-DG R5141 RLESViUTC‘CéD mammnmr

    

 

 

 

 

scrwnv (”fig siren PIPE curls nzrsrrr mom
BfiQOFjl-llllGL l' E] IPRIIIIIIW '1 I2 I C}
1 I_FIN_CLEIIN I 135. PRIME? 3 I 1 ;
11_IIIT_PLCI‘I1T I 135. PRIMRV 3 h 1
1_CHRSSIS 1 135. PRII'IBV 3 l 1
2_rLoon_rnnrlE I 135s rnrmnv a u 1
3_Irn_unl.r.s1 a 135s murmur 3 a 1
a_rm_uaus2 a 135. rnrmnv 3 n 1 -—
h__EXT_HflLLS1 I 135. PRINT! 3 I 1
~_EXT__UIILL82 B 135. PRIMRV 3 k 1
5_ELEC-I'EI:H C 27.. PRIMRV 3 2 1
6_ROOF_INST 3 27.. PRIHRV 3 2 1
7 DOOR HUD I 27.. PRIMRV 3 2 1

2700 PRIMER? 3 2 1

135. PRIME? 3 h 1 '

        

 

 

field I flelete ] Linda: I 5

ii
a

E

 

 

Figure 4.15: Space information

111

4. 5. 2. 3 RELA HONSHIP DA TA

Once the activity station/department name list and the space
information/requirements have been provided, data related to the desirable
proximity/closeness between each of these activity stations needs to be provided. As
described earlier, FactoryPLAN uses Systematic Layout Planning technique developed
by Richard Muther (Muther, 1961). FactoryPLAN accepts relationships in the form of
closeness ratings like A, E, I, O, and U. These closeness ratings and the reasons assigned

for these ratings were presented in Table 4.3 and 4.4, respectively.

In order to input relationships for the departments, the user must click on each of
the stations and then the “Edit relationships” tab in the activity/department list dialogue
box (Figure 4.14). The dialogue box named the “matrix editor” appears (Figure 4.16).
The closeness ratings, the reasons for these ratings, and the maximum distance between
the two stations (if required) should be specified here. For example, in the case of
production plant A, the relationship of the main activity station, named l_CHASSIS
(Chassis on wheel and axle pulled into the factory), with the main activity. station,
2_FLOOR_FRAME (Place assembled floor frame with insulation, ductwork and wiring
over the chassis), is an “A”, absolutely necessary relationship due to high proximity or
logic reasons

The MAX DIST value is the maximum distance allowed between activities that still
satisfy the proximity relationship. When the score is calculated on a relationship diagram, if

the distance between the activity pair exceeds the MAX DIST value, FactoryPLAN adds

112

the pair’s relationship weight to the E (Euclidian) score and R (rectilinear) score (a lower
score is better). Specific MAX DIST values can be entered here if desired. Once all the
relationships have been entered, the user should click on the “save” tab in the window

shown in Figure 4.16. The relationship details will be saved as a relationship/AMX file.

Bel ti in bet-eon AGGREGATE OBS
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9_rrrr_rnrrsrr 0.9 0 0a 0.0 0.0
n_rnn_an_.lsr 0.0 u 0:: 0.0 0.0
nLna—our 0.0 u as 0.0 0.0 :J

B I I. . II I

 

Humidor I IRKI fl

 

 

Figure 4.16: Relationship input window
F actoryPLAN can generate a Relationship Chart using the above supplied data. In
order to do so, the user should click on the “Insert Relationship Chart” tab in the
Chart/Data drop down menu. F actoryPLAN ’3 relationship diagram visually represents the
relationships between various areas and allows the user to create, manipulate, and score

the diagrams, while ensuring that no relationships are ignored.

113

4. 5. 2. 4 GENERA 7 L AND MANIPUIA TE LA YOU'I'S

After both the space information and activity relationship data files have been
created and saved, the user is ready to create a layout. In order to draw the space and
relationship based layouts, the user must click on “Draw Relationships” tab, which is
located under the diagram drop down menu tab. FactoryPLAN allows the user to select
space boundaries, the method by which the activities are to be inserted, and the
diagraming method. The space and relationship files can be specified here so that
FactoryPLAN can use those data to draw the layout. Figure 4.17 shows the “Draw
Relationship Lines” dialogue box. After entering all the required information the user

should click the “OK” tab.

 

 

 

 

 

 

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iii-Diagdew ,__;_--- _:__'_ - IW.::a_____._-,__s__,__.f." __ 2,1 . '_ ..":__-:__~_M.__-_ .. .

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510 Ha... I [cmuppavderuad |

 

 

 

 

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Figure 4.17: Draw Relationships Lines

 

 

114

When the user clicks “OK”, FactoryPLAN returns to the drawing screen and
searches for existing activity symbols. If the layout is being prepared from scratch and
the departments/stations have been specified but not been drawn, the window stating
“Workcenter points do not exist” in Figure 4.18 will appear. When “OK” is clicked at
this box, F actoryPLAN will prompt the user at the command line to pick a location for

each of the work centers (activity stations) specified in the activity/department list.

WWef 130": Ch I'Di 8368!.

UK I

Figure 4.18: Workcenter Points

 

 

Based on the user’s knowledge of the production process, he/she can position the
activity stations when FactoryPLAN requests their placement. Afier all the stations have
been placed, the user can then readjust/reposition stations to obtain a better layout (at this
point, the user should concentrate only on the “A”, absolutely necessary relationship).
The layout then prepared can be scored using the “Score” option under Diagram drop
down menu. The score window is shown in Figure 4.19. The user, based on the space
information and personal knowledge of the production process, can specify the Min/Max
scoring distance for each of the closeness ratings in this window. The basis for score

calculation can be specified here, too.

115

 

FactoryPLAN Sect 9 . . . l I” 5"

 

”Shh lriormation- ' “““"" "w‘#" ’ “A ’"’” ’ "“‘“’ " ' Mir/Max 5m Drum: ' ""“i'

r‘ MakeSideofLaywt ‘ lnfeel ;.
; . w , ‘ 1 mm —;
‘ " MaxlDist.
[7 lgmreDistanoesWfliiSpaceBwidaies H ODist

a i
—Cablate8webasedon‘MHH‘M’T m,_ a
i P” ——. ‘ ‘ M'nXDbt ‘
1 6‘ i Distangg F BeclihearDistance

rm cm] usual

 

 

 

 

Figure 4.19: FactoryPLAN score
Afier providing the required information, the user can click on “OK”. FactoryPLAN
displays the score for the present layout by recalculating the relationships. Figure 4.20
shows the different types of scores FactoryPLAN calculates. The following section will
describe each of these scores in detail.
F wctowPLAN Score

(s-wum ww~ 5.5m. ' mm asap; Hum
EPBHonP 318872 1290 68.1 17113

 

 

 

 

 

 

xm l H ICJE::JE:1T

’x'r'ifi’lwlL-BIJOUISIIJFZ I Save... I Loud... ” I Dish ,. I

 

 

 

Figure 4.20: Types of Score

116

4. 5. 2.5 SCORE
The Layout Column contains the layout slide name that was specified in the Score dialog
at the time the layout was scored (EAI, 1999).
0 The Weighted column shows the layout score, which is the sum of the
relationship line values, each of which is computed using the formula:

Length X Weight

Where
Length = length of the relationship line
WeighF relationship weight for the level of relationship (as specified in

FPEDIT)(EA1, 1999).

o The E-Score column shows the sum of the relationship weight values of those
relationships whose Euclidian distance (the length of a single segment line
directly connecting the workcenter point locations) falls outside the specified

maximum/minimum distance values (EAI, 1999).

In the E-Score field, relationship weight values are not multiplied by length as
with the Weighted-Score field, but rather they are simply weight values or
“stepwise. " The best possible score is “0”, (that is, all relationship distances fall

within the respective max/min distance values).

0 The E% Score column shows the layout’s percent of optimal quality, when all

relationships would fall within respective maximum/minimum distance values.

117

An E% Score of 100 would correspond to an E-Score of O. E% Score is calculated

by subtracting fiom 100% the actual E-Score divided by the worst possible score.

( Actual_E-Score)
13% Score = 100% -

 

(W orst_Possible_E — Score)

0 R-Score and R% Score are similar to E-Score and E% Score, with the exception
that relationship line length is calculated as rectilinear distance (the length of a
two-segment line, one segment horizontal, one segment vertical) between the
workcenters.

The analysis for selection of the best layout can be based on all the scores defined

above. For this research, the author would like to focus the readers attention on the

weighted score, E score, and 13% Score only.

4.5.2.6RESULTS

Based on the above supplied data, the author produced five difl‘erent types of
layout for both the Production Plants. These layouts are shown in detail in Appendix B.
The different layout patterns explored by the author are displayed in Table 4.10. The

existing layout in the case of Production Plant A was a U shaped layout.

118

Table 4.10: Layout Patterns explored

 

 

 

 

 

 

 

 

 

 

Nos. Name Pattern
l Straight-line layout
2 L Shaped layout
3 Z Shaped layout
_J
4 U Shaped layout
5 S Shaped layout

 

 

 

 

 

 

 

 

 

The following section displays the score obtained for each of the layouts for Production

Plant A.

4.5. 2. 7 PROM/[177’ SCORE

After drawing the different layout options, and after several improvements, the
following proximity scores were generated for production plant A and production plant
B. Table 4.11 and 4.12 display a summary of these results. It can be noticed that the S-

Shaped, U-shaped, and the Z-shaped layout alternatives for production plant A, and L-

119

shaped, S-shaped and straight line layout alternatives for production plant B have
relatively better proximity scores than other alternatives. The scores obtained for
production plant A will be used for further analysis.

Table 4.11: Proximity scores for layouts of Production plant A

 

 

 

 

 

 

 

Layout Weighted E-Score E%Score R-Score R% Score
Stra‘ght’l‘m 351612 870 78.6 1320 67.5
layout

1L Shaped 309125 940 76.8 1480 63.5
ayout

Z Shaped 258139 800 80.3 1320 67.0
layout

‘U Shaped 279823 500 87.7 1170 71.2
ayout

[8 Shaped 258608 420 89.7 810 80.0
ayout .

 

 

 

 

 

 

Table 4.12: Proximity scores for layout of production plant B

 

 

 

 

 

 

 

Layout Weighted E-Score E%Score R-Score R'lo Score
Stra‘ght'lm 275753 485 86.6 805 77.8
layout

I“ Shaped 240532 370 89.8 860 76.3
a OUt

Z Shaped 242717 705 80.6 915 74.8
layout

[U Shaped 241501 775 78.6 1075 70.3
ayout

IS Shaped 264605 500 86.2 1090 69.9
ayout

 

 

 

 

 

 

 

 

4.5.2.7.1 Proximity Scores For Production Plant A

As discussed earlier E% score is one of the major indicators of the quality of the
layout. Though a layout can be selected on the basis of the E% scores alone, both E%
score and the weighted scores have been considered as means of assessing layout

alternatives. For production plant A, seen in the above table, it can be concluded that the

120

S shape layout is the best possible layout option, followed by a U-shaped layout, a Z-
shaped option, a straight-line option, and finally the L-shaped option, based on the space

information and the relationship chart provided.

As the weighted score for the Z-shaped layout and the S-shaped layout are close
to each other, these layouts will be analyzed further.
As defined earlier, weighted score is the sum of relationship line values, each of

which is computed using the formula: Length X Weight.

Though the weighted score of the S-shaped layout is more than that of the Z-
shaped layout, E Score provides a reason for the S shaped layout to be considered better.
The E score is the sum of all the relationship weight values whose Euclidian distance is

not within the specified range. In the case of similar weighted score, the lower E score

should be considered the tiebreaker (EA1, 1999).

Based on the scores shown in Table 4.11, it can be interpreted that the S-shape
layout is the relatively better option, as it has the lowest E Score. Since the S-and U-
shaped layout have relatively better E scores, they can be considered for fiirther
evaluation. Similarly, based on the weighted scores of the five layout options, S and Z
shaped layouts can be considered as relatively better layout options, as their weighted

scores are lower than those of other options.

121

A graph comparing the E Score and the weighted score is presented in Figure
4.21. The closer the intersection point (of the E Score value and the weighted score
value) to the origin, better the layout is. Therefore, it is the S-shaped layout that is better.
This S shaped layout for production plant A is presented in Figure 4.22. Similarly, it can
be seen from the graph in Figure 4.23 that an L-shaped layout is the best layout in case of

production plant B. The other layout design alternatives are presented in Appendix B.

 

E Score vs. Weighted Score for Production Plant A

400000
350000
300000
250000
200000
150000
100000
50000
0

Weighted Score

 

0 200 400 600 800 1000
E Score

 

 

 

Figure 4.21: E Score Vs. Weighted Score for Production Plant A

4.5.2.8 DETAILED COMPARISION OF THE THREE LAYOUT ALTERNA UVES -

From Table 4.11, it can be seen that three layouts, S—shaped layout, U-shaped
layout and Z-shaped layout should be selected for further evaluation. These three layouts
can be compared based on their closeness ratings. For each layout, the total number of A
relationships (absolutely necessary) that have been satisfied can be calculated. Similarly,

the total number of E, I, U, relationships that have been satisfied can be calculated.

Hence, the total for is calculated.

122

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123

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E score vs. Weighted score for Production Plant 8
280000 i
e Stride Ina ~ .
g 2700!!)
3 e S Slmed
no 2600(1)
'6
.3 250000
.9 .Z Shaped
i 240000 W ;
0 200 400 600 800 1000
E Score

 

 

 

Figure 4.23: E Score Vs. Weighted Score for Production Plant B

Each of the relationships among each pair of stations was queried. Based on the values in
Table 4.13. For example, for each A relationship that was satisfied, 80 points were

assigned.

Table 4.13: Points based closeness ratings

 

 

 

 

 

 

Nos. Closeness ratings Points
1 A (Absolutely necessary) 80

2 E (Especially necessary) 60

3 I (Important) 40

4 0 (Ordinary) 20

5 U (Unimportant) 0

 

 

 

 

 

Tables 4.14, 4.15, 4.16, 4.17, and 4.18 show the relationship charts for the five layouts.
The relationship closeness ratings that have been satisfied in each layout have been
depicted in red and the relationships that have not been satisfied in the layout have been

presented in blue.

124

 

125

2240
tisfied in 'S' Shaped layout at Product

ts

Effective pom

1740

S shaped layout points

A points

2800

Total

lant A

1011 p

Ionshtps sa

hip chart for relat'

10118

Relat'

Table 4.14

 

126

2140

Effective points

2160

10118

A poi

U shaped layout points
hart for relat

2740

Total

tisfied in 'U' Shaped layout at Production plant A

ips sa

h

Relationship c

Table 4.15

 

127

Z spaped layout points

A points

hip chart for relat

1900
tisfied in 'Z' Shaped layout at Product

' ts:

Ive pom

Effect'

:2060

: 2660

Total

lant A

1011 p

ips sa

1011811

10118

Relat'

Table 4.16

 

128

ive pointsz1900

Effect

Straight line layout points

A points: 2240
hart for relationsh

Total: 2660

Relat

tistied in 'Straight line layout at Production plant A

Ips sa

ionship c

Table 4.17

129

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wed-er

er

 

L shaped layout points

A points: 2000

hart for relat

1740

tistied in 'L' Shaped layout at Production plant A

ts

Effective poin

1ps sa

:2660

Total
Relationsh

1011811

1pc

Table 4.18

Table 4.16 shows the results of the points analysis. The best layout is the one with the
maximum effective points and minimal points for the relationships not met. Clearly the
S-shaped layout is the best layout in the case of production plant A.

Table 4.16: Results of Point analysis

 

 

 

 

 

 

 

 

 

 

 

T m Mu Total ‘A’ Max. Total

0 .' points possible points of Effective %
Layout for possnble f ‘A’ rel t . ts Efl’ ct'

layout points or . ' no poin .e we
type (A) (B) layout points met (F =A-E) points

(C) ’ (D) (E) _

IS'Shaped 2800 3380 1740 2800 560 2240 66.2%
ayout
U‘Shaped 2740 3380 2160 2800 760 1980 58.5%
layout
12'5de 2660 3380 2080 2800 600 2060 60.9%
avout
Smght' 2660 3380 2240 2800 760 1900 56.2%
km layout
”Shaped 2580 3380 2000 2800 840 1740 51.4%
layout

 

 

 

 

These points can assist in the process of layout selection and layout improvement.

The aim is to increase the effective points and reduce the points on relationships not met.

4.6 SUMMARY

Based on the author’s knowledge and visits to the two factories in Northern
Indiana, the production process of a manufactured home was documented in this chapter.
Also, data collection formats for both space and activity relationships were developed
and documented. Two software programs BLOCPLAN and FactoryPLAN, were
analyzed as possible layout design solutions for the manufactured housing production
plant. Afier detailed analysis, FactoryPLAN was selected. The author visited the factories
on a weekly basis for six weeks and collected the required data, developed relationship

charts, and input this data into the FactoryPLAN software. Five layout options, based on

130

 

the layout patterns, were provided and their scores were calculated. The final section of
this chapter consisted of the selection of layout from the layout alternatives based on the

preliminary score analysis.

131

CHAPTER FIVE
LAYOUT DESIGN PROCESS GUIDELINES FOR

MANUFACTURED HOUSING PRODUCTION PLANTS

132

5.1 INTRODUCTION

The previous chapters attempt to explain the different steps involved in the
process of layout design for a manufactured housing production plant. The techniques
and tools used in the field of industrial engineering were applied to the design of a
manufactured housing production plant. In Chapter 4, the author produced different
layout alternatives for a manufactured housing production plant and analyzed various
effectiveness scores to evaluate different layout alternatives. In this chapter, a set of
guidelines outlining the overall layout design procedure is developed based on the work

done in earlier steps.

This research is a part of a National Science Foundation (NSF) funded project,
named, Modeling of Manufactured Housing Production and Material Utilization. As part
of the data collection process for the Phase I (Production and Material Flow Process
Model for Manufactured Housing), the author visited several manufactured housing
production plants and found that the industry did not follow a systematic process for plant
layout. Therefore, one of the outcomes of the present research work was to prepare
guidelines for layout design. These guidelines can lead manufacturers through a series of
steps or procedures to either design new layouts or to improve existing layouts. A basic
flowchart method was adopted for the preparation of guidelines for the layout design of a

manufactured housing production plant.

133

5.2 FLOWCHART

Flowcharting is a technique that depicts the flow of a process from its initiation to
its conclusion. It can be defined as a method of graphically describing an existing process
or a new process using simple symbols, lines, and terms to present pictorially the
activities and progression in the process (Harrington, 1992). A flowchart can explain an

entire process, while keeping various aspects of that process in perspective.

5.2.1 TYPES OF FLOWCHART (Deneba, 2002)

Flowcharts can be used to present information in a way that it can be easily analyzed
and understood. Flowcharts can be grouped in several ways. Shown below is one of the
most common approaches to classifying flowcharts:

0 Basic flowchart: A flowchart that quickly identifies all the major steps in a process. It
provides a broad overview of a process.

0 Process flowchart: A flowchart that examines a process in great detail. It provides a
comprehensive listing of all major and minor steps involved. It describes how a
process works, or how data is handled by a sequence of processes.

0 Deployment flowchart: Similar to Process flowchart, as it is very detailed, but it also
indicates the people who are involved in a process. It is usefiil when the process
involves cooperation between several functional areas.

0 Opportunity flowchart: Highlights decision steps and check points. It is used for very
complicated processes, because it highlights specific opportunities for improvement.

A process flowchart will be used for preparing guidelines in this research work.

134

5.2.2 FLOWCHART SYMBOLS

As flowcharts are a graphical representation of process/flowfrnformation they require

symbols for the purpose of depiction. Various types of symbols are used in flowchart.

The following section presents the standard set of symbols used for the preparation of

guidelines in the present research work.

 

 

 

 

 

 

—>

5.4

Operation: Rectangle. This symbol is used whenever
a change in an item occurs. The change may result
(tom the expenditure of labor, a machine activity, or a
combination of both.

Boundaries: Elongated circle. An

elongated circle is used to show the beginning and
end of the process. Normally, the word start,stop,
or end is included within the symbol.

Decision point: Diamond. A diamond is put at the
point in the process at which a decision must be
made.

Direction of flow: Arrow. An arrow is used to denote
the direction and order of process steps. An arrow is
used to represent movement from one symbol to
another

Figure 5.1:Standard Flowchart Symbols

(Harrington, 1991)

GUIDELINES FOR MANUFACTURED HOUSING LAYOUT DESIGN

Using the symbols shown above, a process flowchart was developed. It presents

the guidelines for layout design of a manufactured housing production plant. The

flowchart consists of five milestones. Figure 5.2 presents a basic flowchart showing these

five milestones.

135

 

I START J

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PRODUCTION
PROCESS
INFORMATION

1

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1

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AND ANALYSIS FOR
SELECTED
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l

SELECTION AND

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l

LAYOUT
EVALUATION
AND
SELECTION

l
[ FINISH ]

Figure 5.2: Milestones of Layout Design Guidelines

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The following section describes the five milestones presented above in detail.
Figure 5.3 presents a detail process flowchart showing the guidelines for developing a

layout

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Production process information: The major purpose of this section is to understand and
familiarize the reader with the production and the production/assembly process of
manufactured home. The designer must be familiar with the various layout patterns used

in the assembly lines of manufactured home.

Selection of techniques: After the designer understands the production process of
manufactured homes, he or she must determine the technique that will be used to prepare
layout design. Information related to the space requirements of the stations and the aisles
in the manufactured home will be needed. The designer will have to select the approach
he/ she wishes to use for measuring flow for developing the proximity relationships. The
designer can select from two methods of measuring flow:

0 Qualitative flow: The designer will require qualitative information for the layout
design. One of the major methods used to evaluate qualitative flow is a
relationship chart. This method assigns closeness ratings, in the form of A, E, I,
O, and U, to describe the relationships between the stations.

0 Quantitative flow: The designer will require detailed information of quantitative
aspects of flow, like material movement. from station to station, distances between
the stations, overall costs of V production/movement, and amount of inventory
stored inside the plant.

For the purpose of this research, qualitative measurement was selected due to the
following two reasons:

1. With the present infrastructure of the manufactured housing production plants,

there is very limited data available that can be used for the development of F rom-

141

to charts, because From-To charts require detailed information on material flow,
material movement and distance between assembly stations, and inventory of
~difi‘erent material maintained inside the production plant.

2. The data collection required for the development of From-To charts was beyond

the scope of this thesis.

Data collection and analysis for selected technique: Afier the technique to be used for
layout design has been selected, the designer should collect data required by the selected
techniques. For the development of the proximity relationships, a primary relationship
chart should be prepared and finalized based on the input from the production managers.
.In the case of data collection for space requirements of various stations, the designer can

use either floor plans of an existing plant or take in-plant measurements.

Selection and application of layout design tools: The designer should select a software
tool based on the type of layout design. problem. In the case of this research work, as the
layout is being prepared from scratch, the software must be a new construction algorithm
- based software and not an improvement algorithm - based software. The software
programs used for this research were BLOCPLAN and FactoryPLAN. FactoryPLAN was
selected for detailed layout design. Upon selecting the software teal, the designer should
input the space information and proximity relationships. In the case of FactoryPLAN, the

designer is given an opportunity to position the stations based on different patterns.

142

Layout evaluation and selection: The final section of the guidelines is the evaluation and
selection of the optimal layout. Proximity scores are generated for each layout. The
designer can then generate different layout options and calculate scores for each of them.
The layout with the lowest E score is considered to be the best layout. The designer
should seek input from production managers in the manufactured housing industry before

selecting a final layout.

5.5 EVALUATION OF GUIDELINES

The guidelines presented in the previous section were based on the research work
carried out by the author. In order to finalize the guidelines, input from leading industrial
design consultants was solicited. After gathering information frOm two designers and one

of the leading industrial design firms, the author came to the following conclusions.

The process of layout development mainly consists of steps similar to the ones
followed by the author. The process details for layout designs, are either developed and
provided to industrial design firms by clients themselves (for example, the automobile
industry develops its own details and provides them to the designer) or developed by the
industrial design firm internally. Industrial design firms develop process details
themselves or subcontract the process details and layout design part to a firm that
specializes in preparing these details only. Presented below are the steps shown on the
web page of one such specialty firm (ckgp, 2000).

0 Analysis of inter-relationships between processing, machinery, and equipment

facilities required to support production

143

0 Development of material handling systems based on the manufacturing process

0 Preparation of block layouts

0 Development of alternative layouts for clients’ consideration

0 Conversion of existing plant layouts to computerized layouts. If required, field

check, measure, and verify all data and information.

On its website, California Manufacturing Technology center (CMT C), presents one of
its consulting services as plant layout design. It describes the following steps as part of

the plant layout design process (CMT C, 2000):

Defining the requirements of the manufacturing facility

. Specifying the activities that must be performed to meet the requirements
. Defining the process flow, space requirements, and activity relationship

. Evaluating alternative Facilities Plans and Plant Layouts

. Estimating return on investment (ROI) of proposed Plant Layout project

. Selecting and implementing a Facilities Plan and Plant Layout

Based on the information presented above, it can be concluded that the process used by

the author for the development of guidelines is similar to the one actually canied out in

the manufacturing facilities design industry.

144

5.6 SUMMARY

This chapter presented guidelines for the layout design of a manufactured housing
production plant in the form of a detailed process flow chart. The first section described
the purpose of the guidelines and the tool that was used to develop these guidelines.
Different types of flowcharting styles and symbols were discussed. Finally, a detailed

process flowchart with an explanation for each of the sections involved was presented

145

CHAPTER SIX

SUMMARY AND CONCLUSIONS

146

6.1 OVERALL SUMMARY

One of the major objectives of this research was to prepare and present different
design layouts alternatives possible for a manufactured housing production plants. This
objective was achieved, and five different layout options were produced based on various
assembly flow patterns. Also, detailed guidelines for the layout design of a manufactured
housing production plant were produced in the form of a flowchart. Chapter 2 provided a
detailed literature review and an overview of the terminology used in two different areas:
manufactured housing and facilities planning and design. The area of manufactured
housing was firrther subdivided into the manufactured housing industry and manufactured

housing product and process details.

In Chapter 3, a detailed description of the different techniques and tools used in
the field of industrial engineering for production plant layout design was provided. This
was .done mainly to investigate the possible options that were available for the layout
design process. A few of the popular traditional layout design techniques were presented
and different layout types and flow patterns were discussed. Specific techniques
applicable to this particular research work were then discussed, including the
documentation of qualitative and quantitative methods of measuring flow. The qualitative
measure (relationship charts) of flow was chosen for the development of layout design
alternatives. The different software tools used for plant layout design were then

discussed.

147

Two software programs, BLOCPLAN and FactoryPLAN, were acquired for use
in this research. Each of these layout design software programs was then studied and its
applicability in the area of manufactured housing production plant layout design was
described in Chapter 4. FactoryPLAN was considered most appropriate for this research.
Based on the author’s knowledge and visits to the two factories, the production process of
a manufactured home was then documented. Also, the data collection formats for both
space and activity relationships were chosen and documented. The author visited the
factories on weekly a basis and collected the required data. The data were used to develop
relationship charts, and these were implemented into the FactoryPLAN and BLOCPLAN
software. Five layout design options based on the layout patterns were developed and
their effectiveness scores were calculated. The final section of chapter four consisted of
evaluation of the layout design alternatives based on preliminary score analysis.

Based on the production process information and the process of layout design
development, the author then produced step-by-step guidelines for the complete
manufactured housing production plant layout design process. This includes all steps,
from process information to layout selection and industry input. The purpose of these
guidelines is to assist a designer/manufacturer to either design a new layout or improve

an existing one.

148

6.2 SUMMARY BY OBJECTIVES

The overall goal of this research was to understand and develop the layout design

process for manufactured housing production plants.

6.2.1 TO COMPILE THE PROCESS DETAILS OF MANUFACTURED HOUSING

PRODUCTION

Manufactured homes are assembled in production facilities. Two methods were
used to understand the production process better. Existing literature (Senghore, 2001;
Hammad, 2001) that described the production process in detail was referred. In order to
gain specific layout-related production process information, the author visited the two
production plants in Northern Indiana and documented the production process. The
assembly line was divided into four major areas within each major cluster (floors, walls,
roof, interior and exterior finishes): main assembly stations, sub-assembly stations feeder

stations and storage areas.

149

6.2.2 TO UNDERSTAND TECHNIQUES RELATED TO MANUFACTURING
FACILITY LAYOUT DESIGN AVAILABLE IN THE FIELD OF

INDUSTRIAL ENGINEERING

Based on the industrial design-related literature, the author had specified the need
to develop space and proximity requirements. General layout design related tools and
techniques were studied. Different types of layouts, layout problems, and flow patterns
were understood. Specific techniques related to proximity relationships were identified
and their applicability to the manufactured housing industry was studied. After thorough
analysis, the qualitative measures of flow were chosen as the means of defining the
proximity relationships. The process of identification of specific techniques for layout
design was a very important step in this research. It took a lot of legwork for the author to

isolate these techniques.

6.2.3 TO COLLECT SPACE AND PROXIMITY RELATED DATA, BASED ON
THE LAYOUT DESIGN TECHNIQUES AND MANUFACTURED HOUSING

PRODUCTION PROCESS DETAH.S

In the case of space requirements the scope of the work was easy to define. The
author developed a data collection table and took detailed measurements of the major
station types classified under each cluster for production plant A. In the case of
production plant B, most measurements were obtained from the floor plan provided by

the manufacturers.

150

The author .then developed relationship charts based on her knowledge of
production process. This involved using information from the production process and the
relationship chart development techniques. The production managers at the two case
study production plants reviewed these charts. A relationship chart developed for
production plant A is presented in Table 4.6. The process of data collection was an

individual contribution of the author.

6.2.4 TO DEVELOP A LAYOUT DESIGN FOR THE MANUFACTURED

HOUSING PRODUCTION PLANT

A substantial amount of research was required for attaining this objective. Two
major software programs were studied for the purpose of the selection of a software tool.
They were BLOCPLAN and FactoryPLAN. First, BLOCPLAN was investigated. An
example layout design problem was defined and space and relationship-chart related data
was developed and used as input. BLOCPLAN only accepted 18 stations, the individual
length/width ratio of the stations could not be defined, and the user could not specify the
layout patterns. Due to these limitations, the author searched for other layout software
and found that FactoryPLAN as anOther possible software option. FactoryPLAN (a
commercial software as part of the comprehensive FactoryCAD package) was obtained
on a short-term loan basis. This software was a very good fit for the requirements of
manufactured housing production plant layout design. The author spent considerable time
understanding the software. The data collected fi'om Production Plants A and B were then

fed into this software, and layouts based on different patterns were generated.

151

FactoryPLAN provided the user with an option to attain a score based on the proximity
relationships. These scores were generated for production plants A and B. Finally, a
preliminary analysis of these scores was carried out to evaluate various layout design
alternatives. Understanding and documenting and finally selecting the software for the
purpose of layout design was an important step in this research. The author herself ’
specifically did this. Most importantly, the author devised the process of layout analysis

and selection methods.

6.2.5 TO FORMULATE LAYOUT DESIGN PROCESS GUIDELINES BASED ON

OBJECTIVES 1 TO 4.

Based on knowledge of the production process, data colleCtion (space
information & proximity requirements) and layout generation, the author developed a
detailed, step-by-step process model for the layout design process of the manufactured
housing industry. The process model was divided into five major sections, (a) Production
process information, (b) Selection of techniques, (c) Data collection and analysis for
selected techniques, (d) Selection and application of layout design tool, and (e) Layout
evaluation and selection. The guideline sections were firrther documented in details.

The guidelines developed in the previous stages were then compared to those
developed by industrial design/ process design consultants. The design layouts prepared
were also presented to the production managers in manufactured housing industry, who

assessed their feasibility. The development of guidelines was a contribution of the author.

152

6.3 LIJVIITATION S OF RESEARCH

One of the major limitations faced in this research was the unavailability of
sufficient data to analyze proximity relationships based on quantitative measure of flow.
In order to collect simple data related to material flow, an idea of the level of inventory
maintained in the plant is needed. Since no proper documentation existed and the efforts
required to develop this information was beyond the scope of this research, the qualitative
method was selected. Specific limitations related to the layout design have been

summarized in the following section.

The layout alternatives are developed based on the closeness each station shares
with every other station on the assembly line or the closeness rating among the stations.
Therefore, in this research, utilization of space and proximity relationships is the major
consideration for the process of layout design. The reader is requested to look at these
layout alternatives from the point of view of space management and not that of

productivity improvement.

The layout alternatives produced in this research are two-dimensional. The layout
alternatives have not been given a third dimensional perspective. Upon application of this
third dimensional perspective, a necessity of review of certain parameters might arise;
these issues have not been considered in this research. The cost factor associated with the
actual construction of any of these layout alternatives has not been considered in this

research.

153

During the process of data collection it was realized that both single-section homes
and multi-section homes were built in the same premises. It was noticed that the process
of handling this situation of mix product production is more dependent on the scheduling
of these products rather than a space management issue. As both the process of
construction and material required for construction for both products is similar, they
follow the same path along the assembly lines. The major difference that appears is the
difference in the time taken for the production of these two product types. Therefore the

issue of mix product types was not addressed in this research.

6.4 CONCLUSIONS

Though manufactured homes have come a long way from recreational trailers,
there has been very little effort to improve the production plants in which they are
constructed. There is no standard method or procedure adopted to prepare a layout for
these production plants. This industry lacks any informationassociated with the process
of layout design of a manufactured housing production plant. There is a need to learn and
adopt techniques and procedures from other disciplines that are more knowledgeable in
this area. This research is the first stepping-stone to bridge the gap between the
manufactured housing industry and more developed industries in the area of production
plant layout design. This industry should analyze and understand the production
processes of other progressive industries, like the automobile industry and based on the
feasibility should learn/adopt and transfer techniques used in that field. The following

section presents the major conclusions from this research work:

154

The author observed that a U-shaped layout is the most common layout in
manufactured housing production plants. Based on the scores obtained for the
different layouts, several layout options are feasible, and manufacturers should
not limit themselves to one particular layout. As this industry is a labor-intensive
industry it has this opportunity to play with different options and is not tied down
to the limitations of fixed machine/equipment-based layouts. One of the best ways
for finding out the best solutions is to calculate the time a worker spends to get the
subassembly or raw material to the main assembly station. Also, the assembly
line design/ pattern should determine the building shape and not vice versa. In the

latter case, the author observed that space is wasted or is under-utilized.

The author strongly believes that manufacturers who are developing layouts
should either follow a methodical guideline (like the one provided in chapter five)

or a checklist in order to develop a design layout.

All the participant parties in this industry should be educated in the area of the
production process and design. Training should be provided to all members of the
industry, especially the workers. As these are the peOple who have the maximum

experience in this area, they would be the best guides to better layout design.

In the long run, the author believes that the present production process should be
studied in greater detail and certain radical changes could be made, alleviating

change/improve the present layout design limitations.

155

o Manufactured housing industry is a labor-intensive industry. Though this allows
for a lot of flexibility for design, manufacturers should consider implementing
certain automation. Specific areas like interior wall fabrication and cabinets
production should be mechanized to improve and speed up the production
process.

This research provides insight into and an understanding of various parameters

related to the manufactured housing layout design process. Manufacturers can use the
different layout options and the process guideline model and tailor them to their

requirements.

6.5 AREAS OF FUTURE RESEARCH

The three layout alternatives selected from the five layout alternatives can be
studied from the Three-Dimensional perspective. The layouts must be analyzed and based
on the changes/additions that occur, new solutions to these layouts could be provided.

Also individual cost calculations must be carried out for the selected layouts.

Layout development based on quantitative measure of flow

The first obvious area of future research is the development of layouts based on
the quantitative measure of flow for the proximity relationships data input. The author
believes that this type of input would produce more accurate and effective layouts. But,

as this form of flow requires detailed inventory management and material and cost flow

156

analysis, documenting this process will require extensive efforts. This process will
include detailed data collection related to material flow between individual stations and
the costs (material, labor, and equipment) involved. Also, a detailed documentation of the
inventory maintained, both temporary and permanent, is required. More effective layouts
can then be developed based on both qualitative and quantitative data and can be
evaluated based on the how effective they are in different spheres, like material
management, labor utilization, and equipment utilization. Simulation can be used to study
the efficiency of the layouts in these areas, and different ‘that-if’ scenarios could be

carried out to produce optimal solutions to plant layouts.

Optimal layout design and optimal production process integration

Extensive research has been carried in the field of manufactured housing
production process development. Based on this research generic production process
details can be simulated to develop an optimal production process. Once the optimal
production process has been developed, the layout design techniques and tools developed
in this thesis can be used to prepare an optimal layout. The detailed inventory
management can be a strong input for the development of an optimal layout. This optimal
layout can be then used as a template and manufacturers can then input their Specific

production process details and customize the layouts to their needs.
Supply chain management perspective

The complete manufactured housing industry can be studied from the supply

chain point of view. The overall process, from the supplier to the consumer, can be

157

studied and analyzed and possible optimal locations of manufactured housing production
plants can be suggested. In the area of product development, radical changes can be
suggested in the manufactured homes themselves. Their feasibility can be studied based
on how well these changes satisfy the structural requirements, transportation limitations,
and consumer demands. These changes will also affect the production process. Again,
simulation can be used to assess the various options and select the most effective

solution.

Total quality management in production process

Also, the area of Total Quality Management should be explored. The present
production process should be studied and possible areas of quality improvements should
be identified. After each cluster is installed, there should be quality checks so that rework
can be avoided. The level of automation in this industry is extremely low as compared to
other growing industries. Each section of the plant should be studied for possible areas of
automation, not only to improve the process but also to improve the quality of the
product. Also, research studies could be carried out to access consumer satisfaction in
areas of space, quality, and durability of the product, and based on the results, possible

changes in manufactured homes could be suggested.

158

(Albern, 1997)

(Apple, 1963)

Apple, 1977)

(Anzer, 2002)

(AutoB, 2002)
(Martinez, 1998)

(Bernhardt, 1980)

(Census, 2000)

(CMTC, 2000)

(Deneba, 2002)
(Dictionary, 2002)

(Donaghey, 2000)

(EA1, 1999)

(Hammad, 2001)

(Heragu, 1997)

REFERENCES

William F. Albern., M. D. Morris.,(1997), “Factory-Constructed
Housing Developments” C R C Press LLC

James M. Apple (1963), “Plant Layout and Material Handling”,
The Ronald Press Company New York.

Apple, J .M., 1977, “Plant Layout and Material Handling”. 3rd
edition, John Wiley & Sons, New York.

Anzer Enterprises, Manufactured Home Division
http://wwwrebelhome.net/histoghtml

Automated Builder, January 2002
Introduction to EZSTROBE — Tutorial

Aurthur D. Bernhardt (1980), “Building Tomorrow: The
mobile/ manufactured Housing Industry” Massachusetts Institute
Of Technology, The MIT Press, Massachusetts, Cambridge, and
London, England.

US. Census Bureau, U.S. Commerce Department.
http://www.censusgov/pub/const/mhs/mhstabplcmnt.pdf

California Manufacturing Technology Center,
httfl/www.cmtc.com/services/plantlayout.asp

http://www.denebmm/community/howto/flowcha_rts/defafult.html
www.dictionar'Lcom

MHAND, BLOCPLAN 2000, Donaghey and Pire, Industrial
Engineering Department, University of Huston

Engineering Animation, Inc., FactoryPLAN, Factory 1999.

Hammad AA. A., (2001) “Simulation Modeling for ManufactUred
Processes in Construction”, Masters Thesis, Department of Civil
and Environmental Engineering, University of Cincinnati, Ohio.

Heragu S. S., (1997) “Facilities Design ”, PWS Publishing
Company, Boston

159

(HUDMHCSS, 1999) Chapter XX~Offrce Of Assistant Secretary For Housing

(Ireson, 1954)

(Int Pub, 1998)

(OWEN, 2002)

(MHI-l)

(MHI-Z)

(MHI-3)

(MHI, 2000)

(MHRP, 1996)

(MHRP, 1993)

(Muther, 1973)

(NAHB, 1998)

(Palekar, 1998)

Federal Housing Commissioner, Department Of Housing And
Urban Development

Part 3280—Manufactured Home Construction And Safety
Standards
wwwggcess.gpo.gov/nara/cfi/waisidx_99/24cfi'3280_99.html

William Grant Ireson (1954), “Factory Planning and Layout”
Prentice—Hall, Inc. New York

http ://www.tpub.corn/progjntro/1 b. htrn

Facility Layout and Relayout Tool (FLRT), Engineering
Animation Incorporated (EAI)
http://wwwowerLSiec.com/downloadlflrtdoc

Manufactured Housing Institute,
http://www.mfghome.org[fast factshtml

Manufactured Housing Institute,

http://manufacturedhousing.orglguick facts/industg overviewht

Q1

Manufactured Housing Institute,
http://wwwmfghome.orglstatistics/costshtml

http://wwwmfghomeorgZMC industg statisticshtml

Burkhardt, T. H., Mireley. S. L., Syal. M., (1996) Manufactured
Housing Research Project, Michigan State University, East
Lansing, Michigan.

 

 

Warner, Kate, and Johnson, Robert, (1993), Manufactured
Housing Research, Project Michigan State University, College of
Architecture and Urban Planning, Ann Arbor, Michigan

Muther R., ( 1973 ), “Systematic Layout Planning”, 2"d edition,
Cahners Books, Boston

“Factory And Site-Built Housing A Comparison For The 21St
Century”, October 1998, NAHB Research Center Inc, Upper
Marlboro, MD

Palekar.U. S., (1998) Lecture Notes, Plant Layout, IE 261:

Facilities Planning and Design, Mechanical and Industrial
Engineering, University of Illinois at Urbana—Champaign.

160

(Reed, 1967) Reed R. Jr., “Plant Layout: Factors, Principles, and Techniques”,
Richard. D. Irwin

(Senghore, 2001) Senghore Omar, (2001)“The Production and Material Flow
Process Model for Manufactured Housing”, Masters thesis,
Construction Management Program, Michigan State University,
East Lansing, Michigan.

(Sule, 1988) Sule D.R. (1988)“Manufacturing Facilities - Location, Planning,
and Design”, PWS-KENT Publishing Company, Boston.

(Syal & Mehrotra, 2001) Syal M., Mehrotra N., “Manufactured Housing Trends and
, Regulations in Michigan” Construction Management Program,
Michigan State University, East Lansing, Michigan.

(Tompkins et al., 1996) Tompkins J. A., White J. A., Bozer Y. A., Frazelle E. H.,
Tanchoco J. M.A., Trevino J ., (1996) “Facilities Planning”, John
Wiley & Sons, Inc. '

(Willenbrock, 1998) Willenbrock Jack H., (1998), “Residential Design and
Construction”, Prentice Hall, New Jersey. '

161

APPENDIX A

162

Production Plant A

Space R uirements station No. 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Area Major Major Raw Rawmaterial
name Description Station Type (Pb) activities material supplied from
Installation of floor ' assembly
Floor 'oist station 1200
Bring in
feeder station chassis chassis external storagg
Pipeline &
ductwork
Install Rock subassembly
Insulation insulation station
Pipeline &
Install uctwork
pipelines & . subassembly
feeder station 1200 ductwork ductwork station
Space R uirements station No: 2
Cluster Area Major Major Raw Rawmaterial
name Descn’ption Station Type (1*b) activities material supplied from
Main assembly
Floor Floor decking station 1200
Installation Floor joist
of floor joist members ceder station
rnstal' 1 Floor boards
floorboards floor boards Ifeeder station
cut holes for
ductwork
Install floor
Subassembly tiles in wet
[station 12001areas oor tiles Vinyl sheet rolls

 

 

 

163

Space Re uirements station No: 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Area Major Major Raw Raw material
name Description Station Type (1*b) activities material supplied from:
place Fabricated
Installation of Main assembly interior interior
Walls (1) interior walls station 1200 walls. walls
place
interior
walls, Fabricated
Installation of Main assembly cabinets. and interior
Walls (2) interior walls station 1200 bathtubs WIS
subassembly set studs on studs,
station [spacing _ l
Insulate,
glue & nail interior walls
subassembly 0 wall subassembly
station 30001boards mall boards station-
wall board
Feeder station 1200 wallboards feeder station
Cabinets &
Subassembly assemble Cabinets & bathtub feeder
[station 1200 cabinets bathtubs [station
Space R uirements station No: 4
Cluster Area Major Major Raw Raw material
name Description Station Type (1*b) activities material supplied from:
install wall
board &
insulation &
Installation of ain assembly interior
walls( 1 ) exterior walls station 1200 Mallboards
install wall
board &
insulation &
Installation of main activity exterior
walls(2) exterior walls station 1200 wallboards
Mallboards,
Feeder station 1200 insulation

 

 

164

 

 

Space R uirements station N o: 5

 

 

 

 

 

 

 

 

 

 

 

Cluster Area Major Major Raw Raw material
name Description Station Type (1*b) activities material supplied from:
[Installation of
electrical wiring & ' assembly
Walls :mech equipment station 2400
wiring and wall board
lFeeder station 1200 ipipg jfeeder station

 

Space R uirements station No: 6

 

 

 

 

 

 

 

 

Cluster Area Major Major Raw Raw material
name Description Station Type (Pb) activities material supplied from:
lMam' assembly
Roof Installation of roof station 2400
set roof tmssl
Subassembly on truss feeder
station 1600 cing trusses station
ue & nail
Subassembly e ceiling ceiling ceiling board
station 1600 ds boards ' ceder station
spray paint
e ceiling &
'ng &
Subassembly loose Mm feeder
tion 1600 insulation 'on

 

 

 

 

 

 

165

 

 

 

Space R uirements station No: 7

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Area Major Major Raw Raw material
name Description Station Type (Pb) activities material supplied from:
Exterior installation of door ' assembly
finishes (1 window station 2400
material for
floor & doors &
window doors & windows feeder
Fwder station 1000 installation windows tion
1000
(same as
door & .
window lmaterial for vinyl sidingsdoors & ‘
installation of roof eeder roof boards with backer windows feeder
Roof boards Fwder station station) installation board [station

 

Space R uirements station No: 8

 

 

 

Cluster Area Major Major Raw Raw material
name Description Station Type (Pb) activities material supplied from:
Installation of roof ' assembly Install roof '
Roof shingles station 2400lshingles ‘

 

 

shingles Fiberglass shingles feeder

 

 

 

 

 

 

 

ceder station 800 installation slungles station
2400
(same as
lshingles
installatio
11 main Installation
exterior installation of Elias“ assembly mbly of exterior exterior ceiling board
tion

tion) jgidipg lsiding [feeder station

 

 

finishes exterior sidings

 

166

Space Re uirements station No: 9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Area Major Major Raw Raw material
name Description Station Type (Pb) activities material supplied from:
Installation of
Interior earpet and ' assembly
finishes “commode station 1200
material for
installation 0am feeder
of foam foam station
installation Learpet feeder
feeder station 800 of carpets carpet station
1200
(same as
material installation
Jshipment of western L
feeder station for site) commodes commodes ceder station
Space R uirements station No: 10
Cluster Area Major Major Raw Raw material
name Description Station Type (Pb) activities material supplied from:
installation of
interior finishes
Interior (appliances and lMarn assembly
finishes drapes) station 1200
Checkup
Electrical.
plumbing.
land HVAC
installation
of kitchen appliances
Feeder station lappliances [appliances feeder station

 

 

167

- _.

*m . _

r:

Space R uirements station No: 11

 

Cluster
name

Description

Station Type

Area

(I‘D)

Major
activities

Major Raw
material

Raw material
supplied from:

 

Interior
finishes

final cleanup and
testing inspection

Main assembly
station

1200

clean up,
testing
inSpecfion.
tires,
materials
lacement

 

Feeder station

1200

material to
be placed in
the home for
onsite
installation

onsite
material
ckage

feeder station

 

interior
finishes

(testing and cleanup
operations

' assembly
station

 

 

 

 

 

installation
of additional
tires and
esting &
[inspection

 

tiresand

 

tires feeder

 

station

 

168

 

 

Production Plant B

Space Requirements station No. l

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Major Major Raw Raw material
name Description Station Type Area (Pb) activities material supplied from:
Installation of floor Main activity
Floor 'oist station 1330
Bring in external
tfeeder station 2000chassis chassis storage
Installation of
Subassembly floor Floor joist
station 77 'oist/boxing members lfeeder station
oist &
uctwork
Install ubassembly
insulation Rock insulatio tion
oist &
uctwork
Install ubassembly
Feeder station 770puctwork ductwork ation
Space Requirements station No:2
Cluster Major Major Raw Raw material
name Description Station Type Area (Pb) activities material supplied from:
Main activity
Floor Floor decking tion 1330
install Floor boards
Feeder station floorboards floor boards lfeeder station
ubassembly
tation 1330

 

 

169

 

 

Space Requirements station No:3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Major Major Raw Raw material
name Description Station Type Area (Pb) activities material Lupplied from:
Rough plumbing an ain activity
Floor electrical tion 1350
Mark wet
&dry areas
cut holes for Install floor
ductwork/decking & Subassembly tiles in wet vinyl sheet
stringer station larcas/ floor tiles rolls
rough electrical and
lumbing & plumbing elec & plumb
ceder station 4 lectrical material orage
Space Requirements station No:4
Cluster Major Major Raw Raw material
name Description Station Type Area (Pb) activities material pplied from:
Installation of Elam activity 005:? interior Fabricated
Walls interior walls ation 27 Is interior walls
bassembly
tion-l, set
sembly
tion
subassembly
tion-2, glue
ubassembly nail to wall
tation 4080 cards
rnstal' l binets &
cabinets & Cabinets & thtub feeder
Feeder station 1530pathtubs bathtubs

 

170

 

 

 

Space Requirements station No:5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cluster Major Major Raw Raw material
name Description Station Type Area (Pb) activities material mpplied from:
Installation of main activity
Malls exterior walls station 270d
place exterior
Fwder station lwalls exterior walls Feeder station
'on of
and and
. 'on 'on
Subassembly 3 510 exterior wall beard
tion (2700+310) board ceder station
hanical,
lectrical & ~
Feeder station lumbing jwiring Feeder station
Space Requirements station No:6
Cluster Major Major Raw Raw material
name Description Station Type Area (Pb) actrvrtres' ' ‘ material supplied from:
' activity
Roof Installation of roof 'on 2700
roof truss
ubassembly on truss feeder
tion ' 135 cing trusses tion
ue & mil
ceiling ceiling board
rds ceiling boards jfeeder station
my paint
Subassembly e ceiling & ' feeder
station 27 11g tion

 

171

 

 

 

 

Space Requirements station No:7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

. Raw material
Cluster Major Major Raw supplied
name Description Station Type Area (Pb) activities material from:
Decking and Main activity
Roof lshrngl' es placement station 2700
. oose
mbly insulation in Ecose insulation
tion roof 'on ceder station
installatr' 'on of
roof boards BS feeder
eeder station 27 OBS) BS 'on
exterior ' tion of ' actrvr‘ 'ty
,fim'shes m: finishes Elfin -
door & doors &
m e...“ r em
Feeder station 153 ‘ tion ' er station

 

 

Space Requirements station No:8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

. Raw material
Cluster Major Major Raw supplied
name Description Station Type Area (mp activities material from:
Roof 2700
thinglee Fiberglass giggles feeder
lt‘eeder station 1 ' tion shingles 'on
exterior
fimmm
vinyl sidings
exterior 'th backer 'dings feeder
Feeder station lS36jsiding Elam tion

 

172

 

Space Requirements station No:9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Raw material
Cluster Major Major Raw supplied
name Description Station Type Area (Pb) activities material from:
interior instal' lation of ' actrvr' 'ty
finishes ' terior finishes 'on 1350
Electrical,
plumbing,
and HVAC
Installation of carpet ' activity
land commode tion
Justallation of Foam feeder
feeder station 72 0am station
'on of carpet feeder
ceder station carpet station
'on oil
estern ‘
lfeeder station 7 mmodes commodes keeder station
Space Requirements station No:10
Raw material
Cluster . Major Major Raw supplied
name Description Station Type Area (Pb) activities material from:
Interior instal' lation of Erato activity
finishes ppliances’ 'on 1350
' tion of
'tchen liances
Feeder station 2 ppliances liances eeder station
terial to be
laced in the
me for
nsite onsite material
Feeder station 42 lation JG [feeder station

 

173

 

 

Space Requirements station No:ll

 

 

 

 

Raw material
Cluster Major Major Raw supplied
name Description Station Type Area (Pb) activities material from:
interior esting and cleanup main activity
finishes operations station 1350
installation of
' 'onal tires feeder

tires and axles Lindon

 

esting &
inspection

 

 

 

 

 

 

final clcanup

 

 

 

174

 

APPENDIX B

175

 

 

BLDc—IN I

 

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SA_DU(;T_PIPE

 

 

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SC_DRYWALL

B_ASM_.INT_WAL

 

CJSMJCABINET

 

 

 

I 4_EXT_.WALLSZ]

 

 

 

SB_CAB|NEI

 

l 5_ELEC—MECH |

 

D_FAB_RF_TRUS

 

 

 

E_CE|LBD_INSU

 

 

SK_RF_TRS_MBR

 

 

 

F__PAINT_CE|L

 

 

l 6_ROQF_INST l

 

 

SD_DOOR ‘
—W'ND 7_DOO.R_W|ND

SLROOF

 

‘_SHlNG

SH_M|ROR_FRDG |8_RO0F._SHINGLJ

 

 

 

SG_WLBDS SF_FOAM

_TO0L JARPT I 9_|NT..F|NISH]

 

 

SI_RANGE_DRPS [ 10_FIN_CLEAN]

 

 

SJ_CMD l11_MAT._PLCMNTI
_SHP_MT , _

 

 

 

BLDG;-OUT

L SHAPED LAYOUT
E% Score: 76.8%

 

 

 

 

MAIN ASSEMBLY STATIONS

SUBASSEIVIBLY STATIONS

FEEDER STATIONS

 

 

176

 

 

BLDG-IN

 

 

I 1_CHASSIS I SA_DUCT_PIPE

 

 

I 2_FLOOR_FRAME I A_FAB_.FLR_JST

 

 

 

 

I 3_1NT_wALLsr I SC_DRyWALL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I 3_1NT_wALLsz I
{-
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I 4-EXLWALL52 I C ASM CABINET m sensory;
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5_ELEC_-MECH 6_ROQF_INST 7_DOOI3_WIND

 

 

 

 

 

 

 

 

 

 

 

 

E_CEILBD_INSU F_PAINT_CEIL
8_ROOF._SHINGL
D_FAB_I{F_TRUS )3 3 E __ R“ (35) F
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z SHAPED LAYOUT Ewe-OUT
13% SCORE: 80.3%

MAIN ASSEMBLY STATIONS

 

 

SUB ASSEMBLY STATIONS

FEEDER STATIONS

 

177

 

 

 

BLDG-IN

BLDq-OUT

 

 

SA _DUCT_ PIPE IA FAB __FLR _JSTI B ASM __CABINETI

 

 

_SHP _MT

SK RF TRS MBR

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_TOOL

 

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I11_ MAT PLCMNII 10 __FIN‘ CLEAN I I 9 _INT __FINISHI

 

 

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SB_CABINET

WIND

SD_DOOR

SHING

SE_ROOF

C-ARPT

SF FOAM

a

 

U SHAPED LAYOUT

E% SCORE: 87.7%

 

 

MAIN ASSEMBLY STATIONS

SUBASSEMBLY STATIONS

FEEDER STATIONS

 

 

 

178

 

 

 

 

 

 

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179

 

 

— MAIN ASSEMBLY STATIONS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SUBASSEMBLY STATIONS
FEEDER STATIONS
I SA_DUCT_PIPE SB_CABINET I %_ ;; E_SABINET|
CD
g 2 FLOOR FRAME 3 INT WALLSI I
'2
| A_FAB_ILR_JST l l 3_INT_\ ALLsz I
4_EXT WALLsz 4 EXT ALLSIJ
inn—Maw,
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F_PAINT_CEIL
6_ROOI[__IN.Sl————l—/7 J
|E_CEIL§D_INSU I SCEBSA’WALL
ID FAB FE TRUS I SK.RF.TBS_MBR
[worm
DOOR
fin
ISE_ROOF
8_ROOF s "I”:SFITNG
1 SH_MIROR_FRDG SG_WLBDS
_Too‘L
9_INT | 10 FIN CLEAN | El MAT PLCMNT 1
7 I F l L 1 l
SF_EéAM WE_DRPS SJ_(iMD
|_ ARPT _SH _MT

E% Score: 89.7%
"A" Relationship

 

mO‘DCI'IH

 

180

 

 

NI‘OG'IEI

 

SA_DUC_T_PIPE

 

SB—CABINEI C_ASM_€ABINET

 

 

 

 

I I_CHASSIS

I |2_FLOOR._FRAME] I 3_INF_\jVALLSl I

 

A_FAB_1~;LR_JST L3_INT_WALLSZ I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A I 4_EXT_\.NALL521 I 4_EXT_‘WALLSrl
5_ELEC_-MECH f f 7
* B_ASM_I.NT_WAL
F_PAINT_CEIL
6_ROOE_INST '
E_CEII.E§D_INSU 3C-DR.YWALL
D_FAB_R_F_TRUS SK_RF_TBS_MBR
7_D0013_WIND
SD_QOOR
_WIND
SE_ROOF
8_ROOF‘SHINGL _SHING
SH_MIRQR_FRDG SG__WLBDS

_TooL

 

I 9_INT__FINISH II 10_FIN__CLEAN llll_MAT_‘PLCMNTl

 

_CARPT

 

SF_FpAM SI_RANQE_DRPS SJ_CMD

_SHPlMT

 

 

S SHAPED LAYOUT
E% Score: 89.7%
"E" Relationship

 

 

 

 

MAIN ASSEIVIBLY STATIONS

SUBASSEMBLY STATIONS

FEEDER STATIONS

 

 

181

If IO‘OG "IE1

 

SA_DU(_ST_PIPE SB_CABINET C_ASM_€ABINET
I I_CHASSIS I |2_FLOORF_FRAME I I 3_TNT_WALLSI I

LAEABFLR JST‘ It? INT_WALLsz I

WALL 82 _ WALLSl

5_ELEC;M§QHf7 -:—~+§L

BLD‘G-IN

 

 

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1 , B_ASM_I‘NT_WAL
1 /' A1N_'r _CEIL
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. \ . Li:EILB_D?(SU I I:SC_DRXWALL I
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[DOOM/WIND

DO,
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1 / SH _MIRQR _FRDG BDS
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9_INT ,7 »

 

 

 

 

 

 

 

 

 

BLDG-OUT

 

 

 

 

 

WW FEW—I
SF_FpAM Sl_RANC_rE_DRPS SJ_C1y1D
_CARPT _SHP_MT

S SHAPED LAYOUT

E% Score: 89.7%

"1" Relationship

MAIN ASSEIVIBLY STATIONS
SUBASSEMBLY STATIONS
FEEDER STATIONS '

 

 

 

182

 

 

 

 

  

 

 

 

50-003
E1Em1mm
mflalmogla mZOF<Hm MQOmE
gmlmomuzla mZOF<Hm >Am2mmm<m5m
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320...? mZOFan >Am§mmm< 23.2
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DEB cm

 

 

 

23.3-... .m. F7325 ZOEUDQOME
52.54.00me memew a gw.©w ”OHOOW gm

 

 

 

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

58:022.-.. 1 HDO><1~ mmgm wH
52.10.0815
.2 3- 2123.0 929310.515 Hmfimddfifi... 1 1
. _|.||._ 0.5.5 0.8.0 m $18.31....
3.35 tn. 0 Nm...<&1§.1m _ Tm..<31...z.1¢ _ EDEEEIM _ _azéwlmoo.l $3.001.

 

 

 

 

 

 

 

..<>.<9.010m Eamalzfid 525313 m.mm<..01mm
.231exm.12m<10

 

 

 

 

 

 

 

183

 

         

 

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