A QYNAMEC TESTER FOE FOLD-MG B-O‘XEQ‘ARQ SCGRELWES Thais 5w i‘kc Doqmo cf M. S. MECHE QM; STIR-1‘13 MUM {TY Reward: Coi’bmm Biake EH 11960 I l! mu; lllzlllsljllsllllll Llll g1 Mlfllfllll u Minn“ ‘ 61 _ 7‘ LIBRARY Michigan State University A DYNAE 3 TESTER FOR FOLDING BOKBOARD SCORELINES By Howard Colburn Blake III AN ABSTRACT Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENC t‘J Department of Forest Products 1960 Approved AN ABSTRACT This study was undertaken to develop a testing device which would evaluate folding boxboard scorelines. The tester develOped bends specimens of folding boxboard scorelines at rates approximating set-up machinery speeds. The an 1 (D 3 through which the specimens are bent is also controlled. The force required to bend a scoreline through any given angle is presented in the form of an oscillograph trace. The force measurements are made by employing bonded strain gages. {a Three scoring variables were used on selecte' Speci- mens in order to demonstrate the device. These variables were MANICO dies versus engraved steel plate dies, seven testin; Speeds, and scores running parallel to and per- pendicular to the machine or grain direction of the Specimen board. Th (0 tester illustrated that scorelines running parallel to the machine direction of the board were less resistant to bending than those running perpendicular to the machine irection. The scorelines made on engraved steel dies were more resistant to bending than were those scorelines produced on hANICO dies. This was because Of a differe.ce in female die width and depth of the score- lines. A DYNAM C TESTER PC a 30KBOARD 5303; By Howard Colburn Blake III A THESIS Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of ti] MASTER OF SCIENC Department of Forest Products - GN113$ 74%;? ii ACKIOWLEDGKZETS This writer wishes to express his sincere apprecia- tion for the assistance and guidance extended to him by Dr. James W. Goff and Dr. Harold J. Raphael during the course of this study. Thanks are also due to his parents, Mr. and Mrs. Howard C. Blake Sr., for their assistance and encouragement during the past year. Finally this writer is grateful to his wife for her encouragement and assistance throughout the course of this work. TABLE OF CONTENTS ACKNOTNLEDGEIVJENTS o o o o o o o o o o o o 0 LIST OF TABLES . . . . . . . . . . . . . . LIST OF FIGURES . . . . . . . . . . . . . . INTRODUCTION PREVIOUS WORK SCORELINE TESTER DESCRIPTION . . . . . . . EXPERIMENTAL PROCEDURE . . . . . . . . . . ANALYSI S OF DATA 0 O O O O O O O O O O O 0 CONCLUSIONS RECOMMENDATIONS FOR FUTURE DEVELOPMENT OF SCORELINE TESTER . . . . . . . . LIST OF REFERENCES . . . . . . . . . . . . APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX A. [11 OPERATION OF THE SCORELINE TESTER SCORING VARIABLES . . . . . . BENDING FORCE - DEFLECTION GRAPHS BENDING FORCE - FREQUENCY GRAPH BREAK ANGLE - FREQUENCY GRAPH SPRINGBACK - FREQUENCY GRAPH . iii Page ii iv ONKNH 20 23 \N KN k)! \0 (D O\ 46 53 54 55 Table II. III. IV. V. VI. VII. VIII. IX. Test Test Test Test Test Test Test Data Data Data Data Data Data Data LIST OF 100 150 200 250 300 350 400 cycles cycles cycles cycles cycles cycles cycles TABLES per per per per- per per per minute minute minute minute minute minute minute Average Values of the Breaking Angle Average Values of Springback . . Average Values of Breaking Force . iv LIST OF FIGURES Figure 1. Specimen Holders . . . . . . . . . . . . . . 2. Bending Force Measuring Circuit . . . . . . 3. Placement of Bending Force Measuring Strain Gages and Gage Beam . . . . . . . . . . 4. Angular Delfection Measuring Circuit . . . . 5. ‘Scoreline Tester Unit . . . . . . . . . . . 6. Scoreline Tester Control Circuits . . . . . 7. Black Diagram of Complete Scoreline Tester Assembly . . . . . . . . . . . . . . . 8. Complete Scoreline Tester Assembly . . . . . 9. Typical Oscillograph Traces . . . . . . . . 10. Full Scale Drawing of the Scoreline Tester unit 0 O O O O O O O O O O C O O O O O 11 13 14 16 17 18 INTRODUCTION The folding box industry has long sought a labora- tory method of testing and evaluating folding boxboard scorelines which would correlate satisfactorily with machine runs. A fast, simple method of testing sample scorelines would enable manufacturers of folding boxes to make the correct selection of rule and makeready at the beginning of the production run. Since the Scores determine the performance of a folding box in the set-up machinery, proper selection of rule and makeready is important to obtain a uniform run. The device herein described was developed to test scored boxboard up to and including 0.040 inch thickness. The Speed of testing may be varied as can the angle of deflection through which the Specimen is bent. Permanent records of the bending force plotted against the angle of deflection may be obtained in photographic form. Springback may be read either from the photographic record or from a Vernier type drum dial. The Specimens used were cut from 0.032 inch thick bending chipboard with a 60 pound per 1000 square feet printed liner wax-laminated to it. The method of testing employed was to bend the Specimens with the device herein described in order to demonstrate its effectiveness. The testing of these Specimens was not conducted to evaluate or compare any materials or combination of variables. The purpose was to demonstrate the use of the device and its ability to show changes in scoreline performance as the scoring variables are changed (A). (A) For a list of scoring variables refer to Appendix B. PREVIOUS WORK Until the middle 1950's, no method of testing score- lines existed except the classic hand and eye method. This procedure involved bending a scoreline and observing the bead formation along the inside of the scoreline. Whether or not the scoreline was too resistant to bending depended entirely on the bender's Judgment. In March of 1956, the Boxboard Research Associates designed a bending tester employing principles originally developed by the Ohio Boxboard Company (3). This pro- cedure paralleled the classic procedure except that rule width, makeready width, and depth of penetration were closely controlled and varied. This allowed any number of these variables to be studied at the same time while employing the same board. Strips of board were scored in several bays of the press, each bay being set up different- ly. The Specimens were then hand folded and compared one against another. D. J. Hine of PATRA deve10ped a scoreline tester employing several conditions encountered in an automatic packaging line (1). The force required to bend a score- line was measured by unbonded strain gages. The angular deflection of the Specimen was measured by a voltage drOp across a 30,000 ohm potentiometer. An oscillograph trace was obtained by feeding the strain gage and voltage drOp signals into the oscillograph. Some variations in testing Speeds were also available. The Ohio Boxboard Score Bend Tester was originally designed to determine the force necessary to set up The folding boxes whose side seam had been glued (2) process was simply to apply force to one corner of a glued blank and measure the amount of force transmitted to the diagonal edge. Later modifications have allowed the force necessary to bend a scored flap to be measured. G. L. Schulz developed a method for testing score- lines using a Baldwin FGT-SR-4 Universal Testing Machine (4). This procedure also employed an auxiliary 500 pound capacity load cell. The Specimens were bent at the rate of four inches per minute. An automatic recorder plotted bending force against angular deflection. Springback was measured by means of a protractor after the Specimens were removed from the holders. In February 1959, the Marathon Corporation developed a machine which.compared Specimens of scored board against Specimens of unscored board (5), The resulting value represented the force necessary to bend the scored Specimen as a percentage of the force necessary to bend the unscored Specimen. The Specimens to be tested ‘were placed across two parallel, horizontal knife edges so that the scoreline Iwui parallel to the knives and. was centered between them. A third knife edge was placed above the Specimen and on top of the score. The base knives were raised causing the Specimen to bend along the single knife edge above. The single knife was attached to a strain gage network which emitted a signal in direct preportion to the force necessary to bend the board. This Signal was amplified and recorded. SCORELINE TESTER DESCRIPTION Specimen Holders The Specimen holders were designed to accommodate boxboard up to and including 0.040 inch thickness. The specimen Size used was one inch by two and one-half inches with the scoreline running parallel to the one inch di- mension. The scoreline was one inch from the end of the Specimen. The holders were constructed of 24248T aluminum stock. They were L-Shaped cantilever beams witn a stiffening member added to increase rigidity. The beams were position- ed on adjacent Spur gears so that the flat surfaces of the longer beam legs form a plane. The surface of this plane lay 0.020 inch below the center of the Spur gear axis and parallel to the tester's base plate. The Specimens were held by means of plates which lay parallel to the hold— ers' surfaces. Shim stock was used to raise or lower the Specimen so that a plane which.passed through the center of the specimen's thickness also passed through the Spur gear axis. Torque Measurement (Bending Force) The force needed to bend the scoreline of a Specimen was measured by a strain gage bridge. The gages were mounted on a cantilever beam which was delfected by one of the Specimen holders as the scoreline was bent. The bridge consisted of four Baldwin-Lima-Hamilton SR-4 FIGURE 1. SPECIMEN HOLDERS pCI/ I] 77—- a L1411 “:53— IL 0.6250— 0/875 ___o.0625 0.2500 fl. K——-K__/.7500————y PCB J.) j}: E: ’ 0.6250—4 ' ' T o./2so———fl- ~<——— 5 ' ‘— “375” ® _ (—— 0/875 mPC/ # ®© é) . gfi/Tzozigémppz‘p 6-32 pcz 0/9/ng0 #26 CD 0/ 770 CD cans—>1 4 0.0625 jx— OOO gg;§%[¢;wo #005,. 0,4 FPO F0 - 375 C[A/T[R Hot? 26 0.4a? 32 / #02/83 4—0.2/88 ——7 #04375 ‘4' 6—0. 2500 O Mama 3 rap/om FOR *6—3z,o.3750 0g 4R1 DING FORCE MEASURING CIRCUIT FIGURE 2. BEN {NIH g) )» Baldwin-Lima-Hamilton SR-A, 350 ohm bakelite strain gage 24 volt dry cell 50,000 ohm micropotentiometer (linear) To amplifier FIGURE 3. PLACEMENT OF BENDING FORCE MEASURING STRAIN GAGES AND GAGE BEAM Strain Gage Arrangement on Beam U ( O Top Bottom Strain Gage Beam Mounting on Tester Force 3> U (3 m 10 bakelite strain gages, all of which were active. The gages had a resistance of 350 ohms each. Two gages were mounted on each side on the beam so that as the beam was deflected, two of the gages were in tension and two were compressed. The Signals generated by the gage bridge were fed into a Tektronix Type 122 Low-Level Preamplifier. The amplified signals were fed into the vertical or Y-axis of a Du Mont model 304-A cathode ray oscillograph. Angular Deflection Measurement Measurement of angular deflection was accomplished by utilizing a voltage increase caused by 5000 ohm linear micrOpotentiometer. The potentiometer was geared directly to one of the Specimen holder's Spur gears. As the spur gear was rotated during the bending of the Speci- men, the potentiometer divided the voltage output of a 45 volt dry cell. This signal was fed into the horizontal car X-axis of the oscillograph. The distance the oscillo- egraph beam traveled horizontally was controlled by Eidgusting the X-axis amplitude control until the beam txraveled as far across the screen as desired for any given number of degrees deflection. Drive Mechani em The motor used to power the device was a Redman, Incnflel BL—6, 0.02 horsepower, 3000 rpm, continuous duty mo tor. FIGURE 4. ANGULAR DEFLECTION MEASURING CIRCUIT @ _@ €® @i‘ij a l. 22% volt dry cell wr 2. 1000 ohm potentiometer (linear) Three position non-shorting switch 3 ‘4. 0-10 volt direct current voltmeter 5 5000 ohm micrOpotentiometer (linear) 6 . _To oscillograph ll 12 The remaining sections of the device were stock items produced by the Pic Design Corporation of East Rock- away, Long Island, New York (A). The parts included a magnetic clutch, medel D2-l, rated at 70 ounce-inches output torque and a series of reduction and idler gears. All gears used were 48 pitch, 0.25 inch bore with either 0.1250 inch or 0.1875 inch face width. These gears served to reduce the drive motor rotation to the desired speed for testing and to increase the motor's output torque. By changing the gear relationships within the gear train, Operations at rates of 100 to 400 cycles per minute were obtained. For the tests, increments of 50 cycles per minute were utilized. The primary purpose of the magnetic clutch was to act as an instantaneous coupler between the gear train and the spur gear holding a specimen holder. Controls The control system for the device consisted of one A. C. circuit which controlled the magnetic clutch and one D. C. circuit which powered the clutch. The 110 V.A.C. circuit was designed to Operate the drive motor and to actuate a Potter and Brumfield type KB latching relay. The function of the relay was to engage and disengage the magnetic clutch depending upon how it received signals. (A) For complete parts list refer to Appendix A. l3 BHZD mMBmma mzHAmmoom .m mmeHm I I”) 73...... * «Hijaxssa. I4 pnmfia poada pao> mm .mH Sundae capommmz .HH swamp Seaeopsq .oH nopflzm pompmoo mampmmsoa maoa oawcam .m gopHSmOLOda .m aopos m>fiam .n nopaSm 30px» mamsdm maon mamcam .0 Amman asapmawma npazv anaaa poaaa nomz .m mmsm opmdaaoaaag .q nopdzm Soanu mandop oaoa mandoa .m meadow pcoaado pooafin mpHo> manem 09 .m meadow psoaaao mmdpmaaopam maHo> OHH 09 .H mBHDomHU domezoo mMBmMH mzHAmmoom .0 amDGHh “flo- H69 (4/69 15 The 26 V.D.C. circuit was used to power the magnetic clutch. The source for the 26 V.D.C. was a laboratory power supply augmented by a Superior model 116 powerstat. 16 FIGURE 7. BLOCK DIAGRAM OF SCORELINE TESTER COMPONENTS 1 7 s 9 2 I V 3 4 5‘ 6 . Powerstat D. C. power supply for clutch Control unit Tester Textronix preamplifier OscilloscOpe Bridge power supply Preamplifier power supply (6 volts D. C.) o Preamplifier power supply (45 volts D. C.) I7 quzmmm¢ mMBmMB mqummoom memquOU .m 1n r... mDGHh I) nm 1 I; : 13th c. TIPICAL OSCILLOGRAPH TRACES ‘* nlq *- 1 N n at naAFFEEGY Machine Direction MANICO Makeready Cross Direction 18, Engraved Makeready Machine Direction Engraved Makeready Cross Direction 19 EXPERIMENTAL PROCEDURE 2O Specimen Material. The test specimens used were taken from materials furnished by the Carton and Container Division of General Foods Corporation. The materials were selected at random from materials used in production. Specimens were cut from blanks constructed of 0.034 inch thick bending chipboard with a 60 pound per 1000 square feet printed liner wax-laminated to it. Specimen Machine Direction The direction of the scoreline in relation to the machine or grain direction of the board was considered by using an equal number of Specimens having scorelines parallel to the grain direction and Specimens having scorelines perpendicular to the grain direction. The widths of the femal dies were greater for score- lines which were across the grain direction. This was done in an effort to reduce the normally high resistance to bending that cross direction scorelines generally have. gpecimen Scorelines One-half of the Specimens were scored on MANICO female dies and one-half on engraved steel makeready plates. The scorelines produced on MANICO dies had widths