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This is to certify that the

thesis entitled

DEVELOPING TEST METHODS TO EVALUATE
PERFORMANCE OR REUSABLE PLASTIC CONTAINERS

presented by
HUSSAIN A. QURASHI

has been accepted towards fulﬁllment
of the requirements for

MASTER degree in PACKAGING

7 14%

Majo rofessor

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University

Michigan State

 

 

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6/01 c-JCIRC/DateDmpGS—sz

 

DEVELOPING TEST METHODS TO EVALUATE PERFORMANCE OF REUSABLE
PLASTIC CONTAINERS

By

Hussain A. Qurashi

A THESIS

Submit to
Michigan State University
In partial fulﬁllment of the requirements
For the degree of

MASTER OF SCIENCE
School of Packaging

2001

ABSTRACT
DVELOPING TEST METHODS TO EVALUATE PERFORMANCE OF
REUSABLE/RETURNABLE PLASTIC SHIPPING CONTAINERS
By
Hussain A. Qurashi.

Reusable/returnable packaging system offers substantial cost savings over expendable
packaging which is usually discarded after just a single use or two.
The purpose of this research is to create a series of integrity type tests that will enable
packaging professionals to evaluate performance of different reusable/retumable
packaging designs and concepts. Nine distinct types of reusable/retumable plastic
shipping containers manufactured by Menasha-Orbis corporation and Monoflo
corporation were subjected to various test methods to compare the relative performance.
The test methods are dynamic longevity test, lid yield strength test, container yield
strength test, double stacked compression test, nesting stop yield strength test, abuse
resistance test, and durability test. These test methods determine the relative resistance of
reusable/retumable plastic shipping containers to deformation, damages, and structural
failures which detrimentally affect the functionality.
The study concluded that these test methods can help in evaluating the performance of
reusable/retumable plastic shipping containers and can yield numerical values for
comparison. Among the nine different types of reusable/returnable plastic shipping
containers tested container type A performed better than other containers and containers

type G and H showed poor performance.

Dedicated to my loving and supportive parents.

ACKNOWLEDGEMENTS

First of all, I would like to thank my mom and dad for their love, encouragement and

support, which are always my motivation to do better things.

For Prof. Singh, your guidance has been valuable thing since we started this work. He is
the most concerned and nice professor I ever met. He taught me how to think wisely and
be patient. He always understood me in all situations and gave a lot of help whenever I
needed. I lack words to explain him but it would be better to say what a wonderful person

he is.

For Prof. Diana Twede and Prof. Brian Fenny, I am thankful for all your suggestions and

comments throughout this work.

I also would like to thank my friends especially Jay Singh for their help and support.

iv

TABLE OF CONTENTS

LIST OF TABLES ..................................................................... viii
LIST OF FIGURES .................................................................... ix
INTRODUCTION AND LITERATURE REVIEW .............................. 1
Molded Plastic containers Manufacturing Process ........................ 8
Injection Molding .............................................................. 9
Compression Molding ......................................................... 9
Blow Molding .................................................................. 9
Rotational Molding ............................................................ 9
Thermoforming ................................................................. 10
Container Types ................................................................ 10
Nest Only Containers .......................................................... l l
Stack Only Containers ......................................................... 1 1
Stack and Nest Containers ..................................................... ll
Collapsible Containers ......................................................... 12
Test Methods ..................................................................... 13
Study Objectives ................................................................ 13
EXPERIMENTAL DESIGN AND TEST METHODS ............................. 18
Container Types ................................................................. 18
Container A ...................................................................... 19
Container B ...................................................................... 19
Container C ...................................................................... 20

Container D ...................................................................... 20

Container E ....................................................................... 20
Container F ........................................................................ 21
Container G ....................................................................... 21
Container H ....................................................................... 21
Container 1 ........................................................................ 22
Test Methods ..................................................................... 22
Dynamic Longevity Test ........................................................ 22
Lid Yield Strength Test ......................................................... 23
Container Yield Strength Test .................................................. 24
Double Stacked Compression Strength Test ................................. 24
Nesting Stop Yield Strength Test .............................................. 25
Abuse Resistance Test ........................................................... 25
Durability Test .................................................................... 25
Failure Criteria .................................................................... 26
DATA AND RESULTS .................................................................. 34
Test Container Evaluation ....................................................... 36
Container A ........................................................................ 36
Container B ........................................................................ 37
Container C ........................................................................ 37
Container D ........................................................................ 38
Container E ........................................................................ 38
Container F ........................................................................ 39

vi

Container G ........................................................................ 39

Container H ........................................................................ 4O
Container I ......................................................................... 41
Comparison of Tested Containers .............................................. 41
CONCLUSIONS ........................................................................... 5 1
BIBLIOGRAPHY ......................................................................... 53

vii

LIST OF TABLES

Tables Pages
1. Dynamic Longevity Test Results .......................................... 45
2. Lid Yield Strength Test Results ............................................ 46
3. Container Yield Strength Test Results .................................... 47
4. Nesting Stop Yield Strength Test Results ................................. 48
5. Double Stacked Compression Strength Test Results ..................... 49
6. Abuse Resistance Test Results ............................................. 49
7. Durability Test Results ...................................................... 49
8. Comparison of Tested Containers .......................................... 50

viii

LIST OF FIGURES

1. Nest Only Containers ........................................................... 15
2. Stack and Nest Containers ..................................................... 15
3. Attached Lid Containers ....................................................... 16
4. Collapsible Containers ......................................................... 17
5. Container A ..................................................................... 27
6. Container B ..................................................................... 27
7. Container C ..................................................................... 28
8. Container D ..................................................................... 28
9. Container E ...................................................................... 29
10. Container F ..................................................................... 29
1 1. Container G .................................................................... 3O
12. Container H .................................................................... 30
13. Container 1 ..................................................................... 3O
14. Dynamic Longevity Test Setup ............................................... 31
15. Lid Yield Strength Test Setup ................................................ 31
16. Container Yield Strength Test Setup ......................................... 32
17. Double Stacked Compression Strength Test Setup ........................ 32
18. Nesting Stop Yield Strength Test Setup ..................................... 33
19. Container E Lid Design (Inside View) ....................................... 42
20. Container F Lid Design (Inside View) ....................................... 42
21. Container G Lid Design (Inside View) ....................................... 43

22. Container E Lid Design (Outside View) ..................................... 43
23. Container F Lid Design (Outside View) ..................................... 44

24. Container G Lid Design (Outside View) ..................................... 44

1.0 INTRODUCTION AND LITERATURE REVIEW

In early 1900’s American Railroads required wooden crates for all
shipments and corrugated use was generally discouraged. Later a court
decision in a lawsuit by a corrugated manufacturer against Southern
Pacific Railroad brought more widespread use of corrugated containers.
The court decision required equal rates for corrugated and wooden
containers. Corrugated fiberboard shipping containers, a paper based
product were widely used as transport packaging after this court decision.
These corrugated containers are most often used commercially only once.
For this reason corrugated containers have been referred to as expendable
containers. Some exception to this are the United States Postal Service
and Frito Lay. The United States Postal Service (USPS) reuses several
million of paper corrugated trays on an annual basis. Similarly Frito Lay
reuses the corrugated boxes for snack foods (a light—weight product)
several times. There is also applications in the automotive industry where

triple-wall corrugated sleeves are reused in returnable packaging.

The use of corrugated shipping containers could involve a huge expense
in disposal and material replacement if they are not recycled. These single
use containers form a significant portion of municipal solid waste (MSW).

Packaging represents nearly one third of the municipal solid waste, and

packaging materials used to transport goods make up nearly half of the

packaging waste.

With the advent of environmental awareness, the cost of disposal has
soared. Knowledgeable groups are projecting a continued rise in these
costs. Traditional methods of disposal: land fill and incineration are
becoming more costly or simply unavoidable. In some areas, land fill and
incineration operations have been banned or taxed by legislation. In other
areas, landfills require separation and sorting of materials or even restrict
certain types of waste altogether. As a result, waste disposal is no longer

just an environmental issue but an economic one as well.

Incineration in the United States is increasingly unpopular because of
concern over its environmental and public health effects. Recycling is an
important way of recognizing and recovering the value of resources
contained within discarded products. It seems that recycling is usually the
most acceptable option. The overall generation of waste and huge
disposal and material replacement expenses can be reduced by using fewer
packaging. Every portion of the waste stream requires its own waste
reduction solution. Because packaging comprises such a large segment of
the total waste, any strategy that aims to reduce packaging can have a
significant impact on the solid waste burden which includes not only the

cost but also the difficulties of managing solid waste. By reducing the

source of the waste, we can reduce the amount of material entering the
waste stream prior to recycling, treatment, or disposal. Source reduction
differs from recycling, which diverts materials that enter the waste
stream and uses them as feedstock to make alternate products. Source
reduction instead prevents materials from becoming part of the waste
stream. One strategy for reducing the generation of packaging waste from
the transport packaging segment is to use reusable/returnable shipping

containers instead of single use paper corrugated containers.

“ A company that makes shipments in single use containers can cut the
quantity of container material needed for one million shipments by 50
percent if it uses these containers twice, by 70.6 percent if it ships its
products in reusable containers that can be used five times and by as much
as 98.5 percent if it switches from single use corrugated shipping

containers to plastic reusable/returnable containers.” (Saphire, 1994)

Reusable /returnable containers can reduce material replacement and
disposal costs significantly. Reusing a container results in less material
being needed to manufacture containers and at the end, less material
requires recycling or disposal. Reusable/returnable containers reduce raw
material use and avoid the need for energy to manufacture or recycle
containers. The cost of material used in packaging systems varies widely

and depends on the products protective and marketing requirements. The

decision to implement a reusable/returnable shipping container requires a
large initial investment for the purchase of such containers. This
investment will depend on the type of container and quantity required.
Most container systems however pay for themselves over a long
productive life. According to Brasington, “The volume of product
shipped and the frequency with which product is shipped determines
how long it takes to payback the cost of a reusable container system”
(Brasington, 1996). The time period over which a reusable/returnable
shipping container is functional (its useful life) affects its total material
cost. Reusable/returnable containers may cost a lot more as compared to
one way containers, so the number of times the container is reused is a
critical variable in calculating total material costs. In addition to this for
comparing the container costs, it is essential to determine the number of
reusable/returnable containers required for one cycle, and the distance
between supplier and user which determines cycle time between
shipments. The cycle time is important because longer cycle times will
require more containers which in turn will increase initial container

investment.

If the width of a trailer is 90 inches, then the width of the pallet used in
that vehicle should not exceed 45 inches. This will allow for two pallet
loads to be placed across the width of the truck. By the same measure,

individual containers should conform to the dimensions of the pallet to

maximize the number of containers that can be placed on that pallet. If
containers are stackable, pallet loads can be built higher, taking advantage
of interior space. This will allow for delivery of more product per

shipment (Saphire, 1994).

Cost efficient transportation requires optimum utilization of available
space inside transport vehicles. The shape and size of containers as well
as how they are loaded into position in transport vehicles will determine
how much of available space is used. To be cost efficient, individual
containers should conform to the interior dimensions of the transport
vehicle. Reusable/returnable containers can be designed to utilize the
space of the transport vehicle and can save shipping (freight) costs. Cost
efficient storage which depends on dimensions and stackability of
containers can be achieved by maximizing the available warehouse and

storage space.

After materials are delivered, single use and reusable/returnable shipping
container systems involve different costs. Single use container system
involve handling and labor costs related to recycling or disposal including
special handling equipment and labor to sort and place items in
appropriate waste containers. Reusable/returnable shipping containers
involve a different set of costs associated with return of containers to

their point of origin including administrative costs for managing and

controlling the flow of full and empty containers, the cost of labor needed
to put empty containers back on pallets for return shipment, freight cost
of hauling back empty containers and the cost of cleaning and repairing
containers. It is clear that reusable/returnable containers require the added
expenses of return transportation. In case of close proximity of supplier
these costs can be less. The longer the distance, the higher the
transportation cost. Another way to reduce the expense of return freight is
the use of containers which nest within each other or collapse to a nearly
flat cofiguration. In this way more empty containers can be returned and

reduce return transportation costs.

Reusable/returnable containers are usually sturdier than one way shipping
containers because they are designed to withstand multiple uses and
therefore can result in reduced damage to product. Reusable/returnable
containers are usually designed ergonomically for safe and easy manual
handling. Ergonomically designed containers can cut handling costs by
reducing workers compensation claims. Reusable/returnable shipping
containers are of uniform shape and size which help reduce some manual

tasks using automation.

Reusable/returnable shipping container system are compatible with just-

in-time (JIT) programs because containers can be moved into production

facilities and then almost immediately moved out again. This means the

supplier can maintain smaller number of containers.

The objective ofjust-in-time delivery is to purchase the required items in
very small quantities on as needed basis for consumption. Just-in-time is
a delivery strategy that manufacturers use to reduce the quantity of
supplies kept in inventory. Instead of making infrequent deliveries of
large volumes that are inventoried over long periods of time, suppliers
make smaller deliveries. The deliveries are made directly to the point of
use on the production line. This results in faster turnover of materials and
reduction in product inventory. Less inventory means that warehouse
space previously used to store parts can now be used for production or
other purposes. In case when the supplier and user are within a close
distance, the carrier can have trucks dedicated exclusively to the just-in-
time shipment. Dedicated shipment routes, shorter delivery distances,
smaller inventories all contribute to the ideal setting for the use of
reusable/returnable shipping containers. The development ofjust-in-time
delivery system has helped spur the use of reusable/returnable shipping
containers in the automotive industry. Implementation of
reusable/returnable containers for just-in-time delivery systems has

created an excellent environment for cost savings.

Reusable/returnable containers can be made from a number of different
materials, including corrugated board, fiberboard, plastics, wood and
steel. The choice of material influences the number of times the container
may be used and ultimately its cost per use. Most reusable/returnable
shipping containers are made from plastic. The most commonly used
plastics are high density polyethylene (HDPE) and polypropylene (PP).

The reasons for their extensive use are listed below:

(a). They are readily available and have a wide acceptance due to
uniform performance and low cost.

(b). They have excellent impact resistance.

(c). They have excellent chemical resistance.

((1). USDA and FDA clearance for use in food and pharmaceutical
industries

(e). Good performance under a wide temperature range.

(f). Molding and design flexibility.

1.1 MOLDED PLASTIC CONTAINERS MANUFACTURING
PROCESS.

There are five major processes used to manufacture plastic

reusable/returnable shipping containers. (Brody and Marsh, 1999). These

are: injection molding, compression molding, blow molding, rotational

molding and thermoforming. Each process is suited to the production of a

range of geometry.

1.1.1 Injection molding; In this process a heated softened plastic material
is forced from a cylinder into a mold cavity, which results in a plastic

product matching the geometry of the cavity of the mold.

1.1.2 Compression molding; This process uses preheated thermosets and
high mechanical pressure to shape the material between male and female
portions of a die. The mold cavities are preheated and parts are removed

after they have been cured under pressure.

1.1.3 Blow molding; This method is most often used to shape hollow
items. A tube of hot melt called a parison is extruded between open
halves of the chilled mold. The mold halves are clamped together,
pinching off the tube at the ends. Air or an air and water mist is injected

into the cavity inflating the soft tube against the mold surface.

1.1.4 Rotational molding; Hollow and seamless products are
manufactured by this process. In this method a powder or liquid plastic is
placed in a mold. The mold is heated and rotated about two perpendicular
axes simultaneously and then cooled. When the material solidifies, the

mold is opened and the part is removed

1.1.5 Thermoforming; This method involves raising the temperature of
thermoplastic sheet material to a workable level and forming it to shape.
This process draws the sheet by a vacuum into an open, chilled mold.
Twin-sheet thermoforming simultaneously works with two sheets, parallel

to each other, and are bonded in the process to gain bending stiffness.

All these processes mentioned above could be used to manufacture
reusable/returnable shipping containers but the most common method used
is injection molding. This method allows intricate shapes to be molded at

high production rates.

There is also a segment of reusable containers that are fabricated. The
most common of these types use plastic corrugated. This material is
usually fabricated into containers using thermal bonding or sonic welding.

In certain applications these containers may also be metal re-inforced.

1.2 CONTAINER TYPES.

Generally there are four categories of reusable/returnable shipping
containers: Nest Only containers, Stack Only containers, Stack and Nest
containers and Collapsible containers. Reusable/returnable shipping
containers are designed with these features to facilitate shipping, handling

and storage.

1.2.1 Nest Only containers; (Figure.l). Nest Only shipping containers
have tapered walls. They can easily be placed into one another or nest
when they are empty. This feature allows for reduction in space for empty

containers.

1.2.2 Stack Only containers; Stack Only reusable/returnable shipping
containers have straight walls and good interior room for optimal
utilization of interior space. Since these containers only stack they take

up a lot of space and are inefficient when stored empty.

1.2.3 Stack and Nest containers; (Figure.2). These containers can stack
on top of each other when full or nest inside one another when empty. In
the stacking feature tops and bottoms are designed to lock into one
another to allow for greater stacking heights. Stack and Nest shipping
containers can have attached or detached lid. In the attached lid container
(Figure,3), the lid is attached by a steel or plastic hinge. These types of
reusable/returnable shipping containers nest inside one another when lids
are open and stack on top of each other when lids are closed. They are
ideal over the road reusable/returnable shipping containers and provide an
excellent unitized load. Detached lid shipping containers are basically
Nest Only containers when the lids are removed but they can stack when

the lids are snapped on.

11

1.2.4 Collapsible containers; (Figure.4). Reusable/returnable Collapsible
shipping containers side and end wall are hinged at the base and fold
inward flat on themselves. These containers have straight walls and
therefore have good interior room. These shipping containers offer

efficient storage when they are collapsed.

Reusable/returnable shipping containers are economically justified over
single use containers because their cost is amortized over their useful life.
They offer reduced damage to the product, help in implementing just-in-
time delivery system, avoid disposal costs, involve reduced labor storage
and freight costs. These savings are often greater than the cost of back
hauling empty shipping containers. Today, reusable/returnable plastic
shipping containers are used in a wide variety of consumer and industrial
applications. The recent growth of reusable/returnable plastic containers
can be attributed to the automotive industry and their suppliers that ship
component parts into assembly plants. Durability, variety of sizes,
dimensions, light weight and cost saving features of reusable/returnable
plastic shipping containers have led companies and suppliers to expand

their use to a variety of products.

12

1.3 TEST METHODS.

Since reusable/returnable plastic shipping containers are available in
different designs, dimensions, and sizes. It is necessary to evaluate their
performance which will be a key economic element to use for justification
of a successful reusable/returnable plastic container program. The goal of
this study is to develop new standards and test methods to evaluate their
performance. These test methods are a series of integrity type tests which
will enable packaging professionals to evaluate the performance and
compare different reusable/returnable packaging designs. This study
determined the performance of reusable/returnable plastic shipping
containers to various types of static and dynamic forces developed in
these test methods. They also provide a uniform basis of comparison
between designs among same or different container manufacturers. Most
of the previous shipping and handling tests used by packaging
professionals have been developed by American Society for Testing and
Materials (ASTM, 1999) or International Safe Transit Association (ISTA).
These test methods in all cases were used to evaluate the performance of
the package and product to various distribution hazards. In most cases the

shipping container was a corrugated box or a wooden container.

1.4 STUDY OBJECTIVES.
The objective of this study was to develop a set of test methods that can

be used to test reusable plastic containers for expected hazards in the

13

transportation, handling, and storage environments. These test methods
were used to compare some of the commercially available reusable plastic
containers. In addition the newly developed test methods will be
recommended to International Safe Transit Association (ISTA) to adopt as

a standard.

 

Figure l. Nest Only containers.

 

 

Figure 2. Stack and Nest containers.

 

Figure 3. Attached lid containers.

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2.0 EXPERIMENTAL DESIGN AND TEST METHODS

In this study, nine different types of reusable/returnable plastic shipping containers were

tested. All containers were inspected prior to testing at the School of Packaging test labs.

The containers were randomly selected for each type of test and were identified with an

alphabetic code described below since they had similar manufacturing process but varied

in design. In each test situation a new sample unit was used.

2.1 CONTAINER TYPES.

The various reusable/returnable plastic shipping containers tested in this study were:

A.

Plastic hinge injection molded HDPE reusable container model CFP 142
manufactured by Orbis-Menasha Corporation.

Wire hinge injection molded HDPE reusable container model CF P 142 manufactured
by Orbis-Menasha Corporation.

Plastic hinge injection molded HDPE reusable container model CF P 182
manufactured by Orbis-Menasha Corporation.

Wire hinge injection molded HDPE reusable container model CF P 182 manufactured
by Orbis-Menasha Corporation.

Plastic hinge injection molded HDPE reusable container model CFP 242
manufactured by Orbis-Menasha Corporation.

Wire hinge injection molded HDPE reusable container model CFP 242 manufactured

by Orbis-Menasha Corporation.

18

G. Wire hinge injection molded HDPE reusable container model DC2115-O9
manufactured by Monoﬂow Corporation.

H. Wire hinge injection molded HDPE reusable container model DC2115-12
manufactured by Monoﬂow corporation.

1. Wire hinge injection molded HDPE reusable container model DC27l7-12

manufactured by Monoﬂow corporation.

Figures 5 to 13 shows the pictures of all containers tested and are provided at the end of
this chapter. The size, weight, material and processing of each container is brieﬂy

discussed in the following section.

2.1.1 CONTAINER A.

This 18.5 x 12.5 x 13 inch HDPE reusable/returnable container as illustrated in Figure 5
is an attached lid stack and nest container with a plastic hinge. The lid of the container is
reinforced with ribs on inner side and interlocks at two places. The container is made
using the injection molding process and has pocket handles for ease of use. The container
has textured bottom and solid draft walls which allow the container to be nested. This

container weighed 6 pounds.

2.1.2 CONTAINER B.
This 18.5 x 12.5 x 13 inch HDPE injection molded stack and nest reusable/returnable
container as illustrated in Figure 6 has an attached lid with a wire hinge. The lid of the

container is supported by ribs on the inside and interlocks at two places. The container

has solid slanted walls which allow the container to be nested and pocket handles for

ease of use. The bottom of container is textured and weighed 6 pounds.

2.1.3 CONTAINER C.

This 18.5 x 12.5 x 13 inch stack and nest reusable/returnable container is made from
HDPE by injection molding. The container has an attached lid with plastic hinges and
pocket handles for ease of use as illustrated in Figure 7. The lid of the container is
reinforced with ribs on the inside and interlocks at two places. The container has smooth
bottom and solid drafted walls to allow the container to be nested. The container weighed

7 pounds.

2.1.4 CONTAINER D.

This 18.5 x 12.5 x 13 inch injection molded HDPE stack and nest reusable/returnable
container as illustrated in Figure 8 has an attached lid with wire hinge and pocket
handles for ease of use. The lid is reinforced with ribs on inside and interlocks at two
places. The container has textured bottom and slanted solid walls to allow nesting. The

container weighed 7 pounds.

2.1.5 CONTAINER E.
This 24 x 14 x 13 inch stack and nest reusable/returnable container is made from HDPE
by injection molding. As illustrated in Figure 9, the container has an attached lid with

plastic hinge and pocket handles for ease of use. The lid is reinforced with ribs on inside

20

and interlocks at two places. The container has textured bottom and solid slanted walls to

allow the container to be nested. The container weighed 8.5 pounds.

2.1.6 CONTAINER F.

This 24 x 14 x 13 inch injection molded HDPE stack and nest reusable/returnable
container as illustrated in Figure 10 has pocket handles for ease of use and an attached
lid with wire hinge. The lid is reinforced with ribs on the inside and interlocks at two
places. This container has textured bottom and solid drafted walls to allow container to be

nested. The container weighed 8.5 pounds.

2.1.7 CONTAINER G.

This 19 x 13 x 9 inch stack and nest reusable/returnable container is made from HDPE by
injection molding. As illustrated in Figure 11, the container has an attached lid and
pocket handles for ease of use. The lid is attached with a wire hinge and is reinforced
with ribs on inner side. The lid has stacking alignment lugs for better stacking on outer
side and inter locks at three places. The container has smooth bottom and slanted solid

walls to allow nesting. The container weighed 6 pounds.

2.1.8 CONTAINER H.

This 18.5 x 12.5 x 12 inch injection molded HDPE stack and nest reusable/returnable
container as illustrated in Figure 12 has attached lid with wire hinge and pocket handles
for ease of use. The lid is reinforced with ribs on the inner side and has stacking

alignment lugs on outer side The lid interlocks at three places. This container has smooth

21

bottom and slanted solid walls to allow the container to be nested. The container weighed

6.5 pounds.

2.1.9 CONTAINER I.

This 24 x 14 x 12 inch reusable/returnable stack and nest container is made from HDPE
by injection molding. As illustrated in Figure 13, the container has pocket handles for
ease of use and an attached lid with wire hinge. The lid is reinforced with ribs on the
inner side and has stacking alignment lugs on outer side. The lid interlocks at three
places. The container has smooth bottom and draﬁed walls to allow nesting. The

container weighed 8 pounds.

2.2 TEST METHODS.

The reusable/returnable plastic containers were subjected to various test methods to
compare the relative performance of containers with different designs and size to a
specified performance criteria. The test methods include measurments of the relative
resistance of reusable/returnable plastic shipping containers to deformation, damage and
structural failures which detrimentally affect the functionality of the container. These test
methods are not intended to evaluate the protection provided to packaged products. The

various test methods that were developed are listed below.

2.2.1 DYNAMIC LONGEVITY TEST.
In this test containers are tested on an Electro- hydraulic vertical vibration table using

random vibration in accordance with ASTM 4728 (Random vibration testing of shipping

22

containers). The vibration table is a model 10000-10 vibration test system with a 60 x 60
platform. The system station was a touch screen computer. The composite truck
spectrum was used. The test container was placed on the platform of the vibration table
with the lid closed. Five containers, each loaded with 40 lbs. of sand bags were stacked
on top of bottom test container for a net total load of 200 lbs. The stack was restrained on
all four sides to prevent from moving off the platform. The system station was used to
drive the vibration table until damage occurred. The data was collected in terms of hours
and minutes of running time before failure. The type of failure was recorded. All nine
reusable containers were tested using the above procedure. Figure 14 shows the test

setup.

2.2.2 LID YIELD STRENGTH TEST.

The test consists of testing one container with its lids closed. The container was placed at
the center of lower platen of a hydraulic compression tester with a 4 x 4 inch hardwood
block centered on the lids. In this test lids were not secured in any manner other than
those that are part of the design of the lids and the container body. The load is applied by
bringing platens together at the rate of one-half (0.5) inches per minute. The compression
tester applies an increasing force to the block. The peak force and corresponding peak
deﬂection when the lids yielded was recorded. The test was repeated on three samples

for each type of container. Figure 15 shows the test setup.

23

2.2.3 CONTAINER YIELD STRENGTH TEST.

In this test a single container with its lids closed was placed at the center of the lower
platen of the compression tester. A pusher, big hardwood block was placed on top of
container. The lids in this test were not secured in any manner, other than those that are
part of the design of the lids and the container body. The compression tester applies an
increasing force by bringing the platens together at the rate of one-half (0.5) inches per
minute. The yield strength of the container is the force at which the container yields. The
peak force and corresponding peak deﬂection when the container yielded was recorded.
The test was repeated for three samples for each container type. Figure 16 shows the test

setup.

2.2.4 DOUBLE STACKED COMPRESSION STRENGTH TEST.

In this test two containers were stacked two high on the lower platen of the compression
tester. The lids of both the containers were closed and were not secured in any manner,
other than those that are part of the design of the lids and container body. The lid area of
the bottom container directly supports the transferred load from the bottom section of the
top container. The compression tester applied load by bringing the platens together at the
rate of one-half (0.5) inches per minute on the top container. The peak force which
makes the test setup yield and the corresponding peak deﬂection was recorded. The test

was repeated on three samples of each container type. Figure 17 shows the test setup.

24

2.2.5 NESTING STOP YIELD STRENGTH TEST.

In this test two containers nested two high were placed at the center of the lower platen
of the compression tester. The lids on the top container were closed and were not secured
in any manner, other than those that are part of the design of the lids and the container
body. The compression tester applied the force directly on the top container at the rate of
one-half (0.5) inches per minute until the bottom container yields. The peak force which
makes the test setup yield and corresponding peak deﬂection was recorded. The test was

repeated on three samples of each container type. Figure 18 shows the test setup.

2.2.6 ABUSE RESISTANCE TEST.

In this test closed, empty containers were dropped from 6 feet manually on each of its
four bottom comers and four top comers. One cycle of abuse resistance represents 8
drops on all 8 comers of the container. This test can be performed using a drop tester or
shock machine. The containers were inspected for damage after each impact. The cycle
was repeated till damage occurred, if the containers were not damaged after the

completion of a cycle. The number of cycles before damage occurred were recorded.

2.2.7 DURABILITY TEST.

In this test the container were ﬁlled with 40 pounds of sand and dropped from 30 inches
using free fall drop tester. The closed containers were dropped on all four of its bottom
edges and all four of its bottom comers for a total of eight drops. One cycle represents
four drops on four base edges and four drops on four base comers. The containers were

inspected for damage after each drop and if the containers were not damaged after

25

completion of one full cycle, the cycle was repeated till damage was observed. The

number of cycles each container type goes through before failure were recorded.

2.3 FAILURE CRITERIA.

The following failure criteria was developed to evaluate the performance of the various
types of reusable/returnable plastic shipping containers and was used to reject containers
when inspected on completion of a test cycle.

a). Material failure.

Any tear, cut or crack of material larger than 1 inch in length or 1 sq. inch in area.

b). Construction failure.

Any separated or broken hinges in the lids.

c). Handle failure.

Any tears, cuts or cracks in handle area larger than 1 inch in length or 1 sq. inch in area.

26

 

Figure 5. Container A.

 

Figure 6. Container B.

 

Figure 7. Container type C

 

Figure 8. Container type D

 

Figure 9. Container type E.

 

Figure 10. Container type F.

 

Figure 11. Container type G.

 

Figure 12. Container type H.

 

Figure 13. Container type I.

an

 

Figure 14. Dynamic Longevity Test Setup.

 

Figure 15. Lid Yield Strength Test Setup.

 

Figure 17. Double Stacked Compression Strength Test Setup.

32

 

l 1
c1 ““rj“:-~-

hf “ _l‘if“‘i‘i"‘- r.
,l‘l H... [H ' 'Il I ‘0'”

1...... .,__‘,lt'~i'l l

11..

 

 

Figure 18. Nesting Stop Yield Strength Test Setup.

3.0 DATA AND RESULTS

The data recorded during the test protocol and the performance of different
reusable/returnable plastic shipping containers is discussed in this chapter. The results of
dynamic longevity test are shown in Table 1. All types of containers developed cracks in
the lid area. Container types A, B, C, D, E, F, and I developed cracks in the lid area after
42 hours, 39 hours, 36 hours, 21 hours, 73 hours, 91 hours and 12 hours respectively.
Containers type G and H developed cracks after 9 hours. The containers can therefore be

ranked as G/H, I, D, C, B, A, E, F in order of increasing strength.

The data for lid yield strength test is shown in Table 2. The lids of A, B, C, D, E, F, G, H
and I type containers yielded at an average compression load of 2602 lbs., 2743.6 lbs.,
1483.3 lbs., 814 lbs., 13821bs., 1266.6 lbs., 423.6 lbs., 422.6 lbs. and 717.6 lbs. with an
average corresponding deﬂection of 2.89 inches, 3.04 inches, 2.56 inches, 2.08
inche52.37 inches, 2.25 inches, 1.42 inches, 1.35 inches and 2.10 inches respectively.
Containers type G and H failed nearly at the same compression force and deﬂection. The

containers can be ranked as H/G, I, D, F, E, C, A, B in the order of increasing strength.

The results of container yield strength test are given in Table 3. Containers type A, B, C,
D, E, F, G, H and I yielded at an average compression load of 1856.67 lbs., 1749.67 lbs.,
1866.33 lbs., 1499.67 lbs., 1178.67 lbs., 1473.33 lbs. 1402.33 lbs., 1403.67 lbs. and

1169.67 lbs. with an average corresponding deﬂection of 1.17 inches, 1.07 inches, 1.15

inches 0.98 inches 1.62 inches, 2.35 inches, 1.81inches, 1.63 inches and 2.44 inches

34

respectively. The containers type G and H failed nearly at the same load and deﬂection.
The containers can therefore be ranked as I, E, G, H, F, D, B, A, C in order of increasing

strength.

The data for nesting stop yield strength is shown in Table 4. Containers type A, B, C,
D, E, F, G, H, and I failed at an average compression load of 4427.6 lbs., 2984.3 lbs.,
2807 lbs., 2842.3 lbs., 2690.3 lbs., 3036 lbs., 2261 lbs., 2410.6 lbs. and 2481 lbs. with an
average corresponding deﬂection of 2.31 inches, 0.85 inches, 0.80 inches, 0.89 inches,
0.68 inches, 0.72 inches, 1.48 inches, 1.71 inches and 1.20 inches respectively. The
containers can therefore be ranked as G, H, I, E, C, D, B, F, A in order of increasing

strength.

The results of double stacked compression strength are shown in Table 5. The containers
type A, B, C, D, E, F, G, H and I failed at a compression load of 1995 lbs., 2307 lbs.,
1927 lbs., 1786 lbs., 2326 lbs., 24401bs., 1260 lbs., 1397.2 lbs. and 1505.7 lbs. with a
corresponding deﬂection of 0.94 inches, 1.33 inches, 1.29 inches, 1.72 inches, 1.19
inches, 1.56 inches, 1.27 inches, 1.69 inches and 1.58 inches respectively. The containers

can be ranked as G, H, I, D, C, A, B, E, and F in the order of increasing strength.
The data for abuse resistance test is shown in Table 6. The containers type A, C, D, G,

and H failed after 11 cycles, 13 cycles, 7 cycles, 2 cycles, and 6 cycles respectively.

containers type B and I showed failure after 8 cycles and containers type E and F failed

35

after 5 cycles. The failure in all the container types occurred at the hinges. The containers

can be ranked as G, E/F, H, D, B/I, A, and C in the order of increasing strength.

The results of durability test are shown in Table 7. Containers type A, B, C, D, E, F, G,
H, and I failed after 46 cycles, 42 cycles, 37 cycles, 22 cycles, 20 cycles, 31 cycles, 10
cycles, 8 cycles and 14 cycles respectively. The failure in all the container types occurred
at the bottom comers during the test. The containers can be ranked as H, G, I, E, D, F, C,

B and A in order of increasing strength.

3.1 TEST CONTAINER EVALUATION:

3.1.1 CONTAINER A.

Sample of container A developed cracks at the comer of the lid in dynamic longevity test
and broke at the hinge in abuse resistance test. In durability test container cracked at one
of the bottom comers while other bottom comers were bent. In lid yield strength test,
container yield strength test , double stacked compression strength test and nesting stop
yield strength test body and lid of the containers were deformed without any signs of
cracks or splits. The Container A showed the best performance compared to other
container types during all tests. Based on Table 2 Container A has average lid yield
strength of 2602 lbs. and corresponding average deﬂection of 2.89 inches. Based on
Table 3 container A has 1856.67 lbs. average container yield strength and 1.17 inches
average corresponding deﬂection. The average nesting stop yield strength of container A

based on Table 4 is 4427.67 lbs. and average corresponding deﬂection is 2.31 inches.

36

3.1.2 CONTAINER B.

Sample of container B developed cracks at the comer of the lid during dynamic longevity
test and in durability test the container cracked at one of the bottom comers while other
three bottom comer were bent. The hinge of all containers broke during abuse resistance
test. In lid yield strength test, container yield strength test, double stacked compression
strength and nesting stop yield strength test, the body and lids of containers were
deformed and there were no signs of splits or cracks. The container showed good
performance in lid yield strength and durability test. Based on Table 2 the average lid yield
strength of container B is 2743.67 lbs. and average corresponding deﬂection is 3.04 inches.
Based on Table 3 the average container yield strength is 1749.67 lbs. and average
corresponding deﬂection is 1.07 inches. The average nesting stop yield strength of

container is 2984.33 lbs. and average corresponding deﬂection is 0.85 inches as shown in

Table 4.

3.1.3 CONTAINER C.

Sample of container C developed cracks at the two adjacent comers of the lid in
dynamic longevity test and in durability test at one of the bottom comers while other
three bottom comers were bent. The hinge of the container broke at two places during the
abuse resistance test. In lid yield strength test, container yield strength test, double
stacked compression test and nesting stop yield strength test, the body and the lids of

containers were deformed and there were no cracks or splits. The container showed

37

excellent performance in abuse resistance and container yield strength test. Based on
Table 2 the average lid yield strength of container is 1483.33 lbs. and average
corresponding deﬂection is 2.56 inches. The average Container yield strength of
container based on Table 3 is 1866.33 lbs. and average corresponding peak deﬂection is
1.15 inches. Based on Table 4 the average nesting stop yield strength of container C is

2807 lbs. and corresponding average peak deﬂection is 0.80 inches.

3.1.4 CONTAINER D.

During the dynamic longevity test procedure the sample of container D developed cracks
at the comers and in abuse resistance test the hinge of the container broke at the comer.
The container body and lids deformed in lid yield strength test, container yield strength
test, double stacked compression test and nesting stop yield strength test but there were
no cracks or splits during these tests. Based on Table 2 the container has average lid yield
strength of 814 lbs. and average corresponding deﬂection of 2.08 inches. The average
container yield strength of container D based on Table 3 is 1499.67 lbs. and average
corresponding deﬂection is 0.98 inches. Based on Table 4 the average nesting stop yield

strength of container is 2842.33 lbs. and average corresponding deﬂection is 0.89 inches.

3.1.5 CONTAINER E.

Sample of container E developed cracks at the comer of lid in dynamic longevity test and
in durability test the container developed a big tear at one of the bottom comers while
other three bottom comers were bent. The lids of the container separated from hinges

during the abuse resistance test. In lid yield strength test, container yield strength test,

38

double stacked compression strength test and nesting stop yield strength test the body and
lids of the container were deformed and there were no signs of splits or cracks. Based on
Table 2 the container has average lid yield strength of 1382 lbs. and corresponding
average deﬂection of 2.37 inches. The average container yield strength of container E
based on Table 3 is 1178.67 lbs. and average corresponding deﬂection is 1.62 inches.
Based on Table 4 the average nesting stop yield strength of container is 2690.33 lbs. and

average corresponding deﬂection is 0.63 inches.

3.1.6 CONTAINER F.

Sample of container F developed cracks at the corner of the lid in dynamic longevity test.
In durability test, the container developed a big tear at one of the bottom comers while
the other three bottom comers were bent. The hinge of the container broke in abuse
resistance test. During lid yield strength test, container yield strength test, double stacked
compression test and nesting stop yield strength test, the body and lids of the container
deformed but there were no signs of cracks or splits. Based on Table 2 the average lid
yield strength of container is1266.67 lbs. and average corresponding deﬂection is 2.25
inches. The container yield strength of container F based on Table 3 is 1473.33 lbs. and
average corresponding deﬂection is 2.35 inches. Based on Table 4 the nesting stop yield

strength is 3036 lbs. and average corresponding deﬂection is 0.72 inches.

3.1.7 CONTAINER G.
During dynamic longevity test of container G, the sample developed cracks at the comer
of lids and in durability test one of the bottom comers of container cracked while other

three bottom comers were bent. In abuse resistance test, the hinge of the container broke

39

at the comer and in lid yield strength test, container yield strength test, double stacked
compression strength test and nesting stop yield strength test the body and lids of the
container were deformed but there were no signs of cracks or splits. Based on Table 2 the
container has average lid yield strength of 423.67 lbs. and average corresponding
deﬂection of 1.42 inches. The average container yield strength of container G based on
Table 3 is 1402.33 lbs. and average corresponding deﬂection is 1.81 inches. Based on
Table 4 the average nesting stop yield strength is 2210.37 lbs. and average corresponding

deﬂection is 0.80 inches.

3.1.8 CONTAINER H.

The sample of container H cracked at the comer of the lids in dynamic longevity test and
at one of the bottom comers in durability test while other three bottom comers were
bent. In abuse resistance test the hinge of the container broke at the comer. The body and
the lids of the container were deformed in lid yield strength test, container yield strength
test, double stacked compression strength test and nesting stop yield strength test but
there were no cracks or splits during these tests. Based on Table 2 the average lid yield
strength of container is 422.67 lbs. and corresponding average deﬂection is 1.35 inches.
The average container yield strength of container H based on Table 3 is 1403.67 lbs. and
corresponding average deﬂection is 1.63 inches. Based on Table 4 the average nesting
stop yield strength of container is 2410.67 lbs. and corresponding average deﬂection is

1.71 inches.

40

3.1.9 CONTAINER 1.

Sample of container I developed cracks in dynamic longevity test at the corners of the
lids and in durability test at one of the bottom comers while other three bottom comers
were bent. In abuse resistance the hinge of the container was broken and the body and
lids of the container were deformed in lid yield strength test, container yield strength test,
double stacked compression strength test and nesting stop yield strength test but there
were no cracks or splits during these tests. Based on Table 2 the average lid yield strength
of container is 717.67 lbs. and corresponding average deﬂection is 2.10 inches. The
container yield strength of container I based on Table 3 is 1169.67 lbs. and corresponding
average deﬂection is 2.44 inches. Based on Table 4 the container has nesting stop yield

strength of 2481 lbs. and corresponding average deﬂection is 1.20 inches.

3.2 COMPARISON OF TESTED CONTAINERS:

Table 8 shows the nine different containers (A through 1) ranked in performance based on
each of the seven different test methods. Since each test method simulates a potential
hazard from the storage, handling and shipping environments, this method can be used to
compare different container designs based on the individual hazard. “The Dynamic
Longevity” and “Durability” tests are the most representative of shipping and handling

hazards for these type of reusable containers.

Based on the results in Table 8, the container with plastic hinges showed better

performance in shipping as compared to those with steel hinges. The use of a plastic

hinge allows ease in recycling after the “useful life” of the container is achieved. The

41

wire hinge containers have to go through a material separation process (wire/plastic)

before they can be recycled.

The type of rib design on the bottom of the lids can also play a major role in the

performance of the container (Figures 19 — 24). This can be seen comparing containers E,

F, and G from the data in Table 8 and the different rib designs used.

42

 

Figure 20. Container F Lid Design (Inside view)

43

 

Figure 22. Container E Lid Design (Outside View)

 

Figure 24. Container G Lid Design (Outside View)

45

TABLE 1: DYNAMIC LONGEVITY TEST RESULTS.

 

 

 

 

 

 

 

 

 

 

 

TYPE OF

TYPE HOURS TO FAIL FAILURE
A 42 Cracks in lid
B 39 Cracks in lid
C 36 Cracks in lid
D 21 Cracks in lid
E 73.3 Cracks in lid
F 91.3 Cracks in lid
G 9 Cracks in lid
H 9 Cracks in lid
1 12 Cracks in lid

 

 

 

46

 

TABLE 2: LID YIELD STRENGTH TEST RESULTS.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMPRESSION DEFLECTION
CONTAINER SAMPLE STRENGTH (LBS) (INCHES)

1 2600 2.95

A 2 2619 2.91
3 2587 2.82

1 2703 3.03

B 2 2781 3.11
3 2747 2.98

1 1559 2.61

C 2 1391 2.56
3 1500 2.52

1 833 2.09

D 2 791 1.89
3 818 2.27

1 1185 2.28

E 2 1553 2.46
3 1408 2.36

1 1201 2.28

F 2 1291 2.22
3 1308 2.24

1 395 1.43

G 2 451 1.41
3 425 1.42

1 415 1.37

H 2 428 1.35
3 425 1.33

1 709 2.07

I 2 719 2.13
3 725 2.09

 

 

 

 

47

 

TABLE 3: CONTAINER YIELD STRENGTH TEST RESULTS.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMPRESSION DEFLECTION
CONTAINER SAMPLE STRENGTH (LBS) (INCHES)
1 1776 1.14
A 2 1888 1.17
3 1906 1.2
1 1744 1.03
B 2 1708 1.06
3 1797 1.12
1 1879 1.14
C 2 1871 1.01
3 1849 1.29
1 1423 0.76
D 2 1567 0.9
3 1509 1.27
1 1165 1.63
E 2 1051 1.39
3 1320 1.85
1 1424 2.17
F 2 1493 2.43
3 1503 2.45
1 1445 1.59
G 2 1397 1.95
3 1365 1.88
1 1461 1.68
H 2 1464 1.70
3 1286 1.52
1 1244 2.76
I 2 1056 1.99
3 1209 2.56

 

 

 

 

48

 

TABLE 4: NESTING STOP YIELD STRENGTH TEST RESULTS.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMPRESSION DEFLECTION
CONTAINER SAMPLE STRENGTH (LBS) ﬂNCHES)

1 4443 2.33

A 2 4383 2.28
3 4457 2.33

1 2961 0.85

B 2 2960 0.85
3 3032 0.84

1 2747 0.73

C 2 2861 0.84
3 2813 0.82

1 2867 0.83

D 2 2861 0.89
3 2799 0.94

1 2708 0.69

E 2 2746 0.73
3 2617 0.63

1 3035 0.66

F 2 3023 0.82
3 3050 0.69

1 2226 1 .45

G 2 2249 1 .52
3 2308 1 .48

1 2371 1 .82

H 2 2309 1 .58
3 2552 1 .72

1 2499 1 .19

| 2 2503 1 .18
3 2441 1 .22

 

 

 

 

49

 

TABLE 5: DOUBLE STACKED COMPRESSION

 

 

 

 

 

 

 

 

 

 

 

STRENGTH.
CONTAINER PEAK FORCE (LBS) DEFL. @ PEAK

(IN.)
A 1995 0.94
B 2307 1.33
c 1927 1.29
o 1786 1.72
E 2326 1.19
F 2440 1.56
G 1260 1.27
H 1397.2 1.69
I 1505.7 1.58

 

 

 

TABLE 6: ABUSE RESISTANCE TEST RESULTS

CONTAINER

~mommonw>

 

NO. OF CYCLES.

TABLE 7: DURABILITY TEST RESULTS

CONTAINER

A

50

46
42
37
30

22
31
10
8
l4

 

NO. OF CYCLES.

 

TABLE 8. COMPARISSION OF TESTED CONTAINERS

 

 

 

 

 

 

 

 

 

 

TEST TYPES CONTAINER
A B C D E F
DYNAMIC 3 4 5 6 2 l
LONGEVITY TEST
LID YIELD 2 1 3 6 4 5
STRENGTH TEST
CONTAINER YIELD 2 3 l 4 8 5
STRENGTH TEST
NESTING STOP
YIELD STRENGTH 1 3 5 4 6 2
TEST
DOUBLE STACKED 4 3 5 6 2 I
COMPRESSION
STRENGTH TEST
ABUSE 2 3 l 5 7 8
RESISTANCE TEST
1 2 3 5 6 4
DURABILITY TEST

 

 

 

 

 

 

 

 

51

 

 

 

4.0 CONCLUSIONS

The test methods developed can be used to differentiate the performance of various types
of reusable/returnable plastic shipping containers. Nine different types of
reusable/returnable plastic shipping containers were tested to compare their relative

performance under a speciﬁed performance criteria. The study concluded the following;

1. Container A performed better compared to all other container types.

2. Containers G and H showed poor performance during all tests.

3. Containers with plastic hinges performed better than the containers with wire
hinges during all tests.

4. The test methods developed were recommended to International Safe Transit

Association (ISTA) and were accepted as Project 3C.

The study showed that certain reusable/returnable plastic shipping containers will

perform better than others based on various design features that permit them to be

nestable, stackable, provide load stability, and last multiple trips.

52

BIBLIOGRAPHY

53

BIBLIOGRAPHY

Saphire, David, “Reusable Shipping Containers”. Delivering The Goods: Beneﬁts of
Reusable Shipping Containers, pp. 5, (1994).

Brasington, Rick, “Protecting Proﬁts With Plastic Containers.” Report on Distribution
Packaging, pp. 21, (1996).

Saphire, David, “Shipping (Freight) Costs”. Delivering The Goods: Beneﬁts of
Reusable Shipping Containers, pp. 6, (1994).

Broady, A. , Marsh, K. , “Boxes, Rigid, Plastic”. The Wiley Encyclopedia of
Packaging Technology, pp.1 10, (1999).

54