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1 Thermoforming QUARTERLY

Contents

Th e rmo f o rm i n g®

Q U A R T E R L Y

A NOTE TOPROSPECTIVE

AUTHORSTFQ is an “equal opportunity”publisher! You will note that we haveseveral categories of technical articles,ranging from the super-high tech(sometimes with equations!), toindustry practice articles, to bookreviews, how to articles, tutorialarticles, and so on. Got an article thatdoesn’t seem to fit in these categories?Send it to Jim Throne, Technical Editor,anyway. He’ll fit it in! He promises. [Bythe way, if you are submitting anarticle, Jim would appreciate it onCD-ROM in DOC format. All graphsand photos should be black and whiteand of sufficient size and contrast tobe scannable. Thanks.]

QUARTERLY

A JOURNAL PUBLISHED EACH CALENDARQUARTER BY THE THERMOFORMING DIVISION

OF THE SOCIETY OF PLASTICS ENGINEERS

EditorGwen Mathis

(706) 235-9298 • Fax (706) [email protected]

Technical EditorDr. James Throne

Sherwood Technologies, Inc.1797 Santa Barbara DriveDunedin, FL 34698-3347

1-800-273-6370 • Fax (727) [email protected]@tampabay.rr.com

SponsorshipsLaura Pichon

(815) 678-2131 Ext. 624Fax (815) 678-4248

[email protected] Quarterly® is published four times an-nually as an informational and educational bulletinto the members of the Society of PlasticsEngineers, Thermoforming Division, and thethermoforming industry. The name, “ThermoformingQuarterly®” and its logotype, are registered trade-marks of the Thermoforming Division of the Societyof Plastics Engineers, Inc. No part of this publicationmay be reproduced in any form or by any meanswithout prior written permission of the publisher,copyright holder. Opinions of the authors are theirown, and the publishers cannot be held responsiblefor opinions or representations of any unsolicitedmaterial. Printed in the U.S.A.

Thermoforming Quarterly® is registered in the USPatent and Trademark Office (Registration no.2,229,747).

These sponsors enable us to publish Thermoforming QUARTERLY

TECHNICAL SECTION

Chairman’s Corner .................................................................. Inside Front CoverMembership Memo: It’s Conference Time Again! ........................................... 2New Members ..................................................................................................... 3Thermoformer of the Year 2006 Nomination Form ........................................ 7Milwaukee Board Meeting Schedule ................................................................ 8Council Report .................................................................................................. 26Membership Application ................................................................................. 33Index of Sponsors ............................................................................................. 36Board of Directors List ............................................................. Inside Back Cover

Lead Technical Article:Enhanced TPO Thermoforming Using High Melt Strength Polyolefin Elastomers .... 10

Industry Practice:Collaborative and Methodical Development Reduces Time From Concept to

Production .................................................................................................................... 15

Industry Practice:Proper Colleting and Collet Maintenance in CNC Routing of Plastic ......................... 16

Industry Practice:History of Thermoforming – Part I ................................................................................. 19

Thermoforming 101:Understanding How a Sheet Stretches .......................................................................... 22

Book Review:The Evolution of Plastics in America (As Seen Through the National Plastics

Expositions) .................................................................................................................. 24

DIVISION ACTIVITIES

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Thermoforming QUARTERLY 2

MEMBERSHIP MEMO

BY MIKE SIROTNAK, MEMBERSHIP CHAIRMAN

It’s ConferenceTime Again!

MEMBERSHIP REPORTas of 6/15/05

Primary Paid .......................1,229

Secondary Paid ......................447

Total Membership ..............1,726

Goal as of 6/30/2005 .........2,000

The last time our conferencewas held in the beautiful

city of Milwaukee, our countrywas still reeling from the dev-astating attacks of 9/11. I willnever forget having to drivefrom New Jersey to Milwaukee,due to the massive airport clos-ings, wondering what thefuture would hold. Nowfour years later, it’s hardnot to think back on thattime and reflect on howmuch has changed andremarkably how muchhas stayed the same. I amvery proud of our mem-bers for their continuedsupport and I am confi-dent that our divisionwill achieve all of itsgoals.

Just a reminder! The reprintsof our very first DVD “What isThermoforming?” have arrivedand are available. Please feel freeto contact any of the Boardmembers to request additionalcopies or visit our website,www.thermoformingdivision.com,for more information.

Recently the ThermoformingDivision donated money to sup-

port a group of doctors andnurses to visit Sri Lanka to aidin the Tsunami relief. Make sureto read the article in this issuefor complete details. It’s anotherexample of the good works yourmembership provides. Scholar-ships, educational equipment

grants, disaster relief donations,educational DVD’s, Thermo-forming Quarterly, technical con-ference and the only industryspecific trade show … all possiblebecause of your continued support.I urge you to continue to helprecruit new members.

This year’s conference should bevery exciting. Hometown boy, BobPorsche, has put together an excit-ing conference. The technical pro-

gram will be cutting edge with afocus on new technology in our in-dustry. Walt Walker and Ed Probsthave searched high and low to bringyou all that is new. The exhibit floorwill be bigger and better than ever.Try to make a point of spending asmuch time as possible on the ex-

hibit floor. The exhibitorsare the backbone of theseconferences. Joe Peters hasput together a very diverseParts Competition. Makesure to stop by and see whatyour competitors are up to.This year we are offeringfour plant tours includingtopnotch processors, PrentCorp. and Profile Plastics.You have to respect thosebusiness leaders that allow

the public to visit their facilities.Steve Murrill and Walt Walker aretwo examples of our industry’s best.

Four years ago, Milwaukee didnot see our best. Let’s make surethis conference changes that. Seeyou on the exhibit floor.

God Bless America!


To Our New MembersPhilip AllgoodMEISmyrna,

Georgia

Jeff BosticThree Four

SolutionsLLC

Bammamish,Washington

James L.Cameron

Barron &Rowson PlyLtd.

Australia

EuclideCeccchin

Omega Tool Ltd.Warren,

Michigna

Ray CollinsAnchor Plastics

MachineryLtd.

UnitedKingdom

Don GerhardtIngersoll RandClemmons,

NorthCarolina

Sheila GreerBenver State

PlasticsDrain, Oregon

Kenneth HeroldRotocast

TechnologiesAkron, Ohio

WHY JOIN?It has never been more important tobe a member of your professionalsociety than now, in the currentclimate of change and volatility in theplastics industry. Now, more than ever,the information you access and thepersonal networks you create can andwill directly impact your future andyour career.

Active membership in SPE:• keeps you current

• keeps you informed• keeps you connected

The question really isn’t“why join?” but …

WHY NOT?

Don HexamerTri City

PackagingWaterloo,

Canada

Ken A. HopkinsAllen, Texas

Daniel W. KingCopley, Ohio

Young Soo KoBorealls

Polymers Co.Finland

Fernando LemosJay Packaging

GroupWarwick, Rhode

Island

John LuscombeIntegrated

CompositeTechnologies

Montezuma,Georgia

Charles MansAzimuth

CustomExtrusionsLLC

Evansville,Indiana

Gary MantylaPlast-Labs, Inc.Lansing,

Michigan

Dick MarrGenpak LLCHolyoke,

Massachusetts

Mark McKaigGenpak LLCMontgomery,

Alabama

William MooreBallwin,

Missouri

John MosherThe Boxboro

GroupBoxboro,

Massachusetts

Charles A.Munson

American Pipe& Plastics,Inc.

Binghampton,New York

TrevorNickerson

PCF/JamestownPlastics

Mayville, NewYork

Fred OllarsabaTempe, Arizona

Thomas ScheinAll About

Packaging,Inc.

Appleton,Wisconsin

ShankaraShettym

ConceptManagementCompany

St. SimonsIsland,Georgia

Ryan SnowAll About

Packaging,Inc.

Appleton,Wisconsin

Harinder S.Tamber

TambarConsultants

Mississauga,Ontario -Canada

Charles TuttyCJK

ManufacturingLLC

Rochester, NewYork

Tim TuttyCJK

ManufacturingLLC

Rochester, NewYork

KeithWoodward

CJKManufacturingLLC

Rochester, NewYork

Jim ZuberskyTPIWhite Bear

Lake,Minnesota


THERMOFORMINGQUARTERLY … A WINNER!

At the recent Antec in Boston,the Thermoforming Quarterlyagain won First Place in theDivision’s Newsletter Contest.Roger Kipp, Division Chairman,is shown presenting the awardto the Thermoforming QuarterlyEditor Gwen Mathis.

In Memory of

James E.

Gilham

On April 27, 2005, JamesE. Gilham of Marlton,

New Jersey passed away atthe age of 78. He was thebeloved husband for 50years to the late Doris E.(nee Homan). Loving fa-ther of Harold S. Gilhamand his wife Lisa ofSouthampton, NJ; DeborahCherico and her husbandJohn of St. Louis Park, MN;Robin Zerillo and her hus-band John of Medford, NJ;Lorrie Fabrizio and herhusband Joseph of WestChester, PA; and 14 grand-children. Dear brother ofMimi Leisy, Betty Danley,Tom Gilham and ButchGilham. A service honoringhis life was held at St.Andrew’s MethodistChurch with interment inLocustwood MemorialPark, Cherry Hill, NJ. Con-tributions in his memorymay be made to the LupusFoundation of South Jersey,1873 Rt. 70 East, CherryHill, NJ 08003. ■



PENN STATE-ERIE ROOMMATES RECEIVE2005 THERMOFORMING SCHOLARSHIPS

JOHN GRIEP MEMORIAL$5,000.00 SCHOLARSHIP

TRAVIS HUNTERPENN STATE - ERIE

SEGEN MEMORIAL$5,000.00 SCHOLARSHIP

JOSHUA SINDLINGERPENN STATE - ERIE

Ken Griep, Chairman of Student Affairs, is pleased to announce the winners of the following scholar-ships. These scholarships will be presented during the annual Thermoforming Conference in Milwaukee.

Travis Hunter is a Senior at Penn State-Erie ma-joring in Plastics Engineering Technology. He

has had extensive experience with thethermoforming process and is currently complet-ing a project that tests the thermoformability of fourdifferent polymers (HDPE, LDPE, PP and PET)with additives. In an earlier project, he used anepoxy compound to form a mold of a product thatis already on the market and tested the permeabil-ity properties of the thermoformed polymer. Travishad an internship at Emerson Appliance Controlswhere he was able to design a new mold. The Man-ager of Engineering at Emerson indicated thatTravis and his partner, Joshua Sindlinger, were thebest interns he’d worked with in his 35 years withthe company. ■

Joshua Sindlinger is a Senior at Penn State-Eriemajoring in Plastics Engineering Technology. He

has had extensive experience with thethermoforming process and is currently complet-ing a project that tests the thermoformability of fourdifferent polymers (HDPE, LDPE, PP and PET)with additives. Josh partnered with his PS-E room-mate Travis Hunter at Emerson Appliance Controls.Josh also worked for Holbrook Tool as an injectionmolding machine operator in the summer of 2000.Upon graduation, he hopes to become a processengineer and then work his way up the corporateladder. ■



THERMOFORMER OF THE YEARCRITERIA FOR 2006

Every year The SPE Thermo-forming Division selects a indi-

vidual who has made a outstand-ing contribution to our industry andawards them the Thermoformer ofthe Year award.

The award in the past has goneto industry pioneers like Bo Strattonand Sam Shapiro, who were amongthe first to found thermoformingcompanies and develop our indus-try. We have included machine de-signers and builders Gaylord Brownand Robert Butzko and toolmakerJohn Greip, individuals who helpeddevelop the equipment and moldideas we all use today. We havealso honored engineers like LewBlanchard and Stephen Sweig, whodeveloped and patented new meth-ods of thermoforming. Additionally,we have featured educators like BillMcConnell, Jim Throne andHerman R. Osmers, who have bothspread the word and were key fig-ures in founding the ThermoformingDivision.

We’re looking for more individu-als like these and we’re turning tothe Thermoforming community tofind them. Requirements would in-clude several of the following:

➢Founder or Owner of aThermoforming Company

➢Patents Developed

➢ Is currently active in or recentlyretired from the ThermoformingIndustry

➢ Is a Processor – or capable ofprocessing

➢Someone who developed newmarkets for or started a new trendor style of Thermoforming

➢Significant contributions to thework of the Thermoforming Divi-sion Board of Directors

➢Has made a significant educa-tional contribution to theThermoforming Industry.

If you would like to bring some-one who meets some or all of theserequirements to the attention of theThermoforming Division, please fillout a nomination form and a one-to two-page biography and forwardit to:

Thermoforming Division AwardsCommittee% Productive Plastics, Inc.Hal Gilham103 West Park DriveMt. Laurel, NJ 08045Tel: 856-778-4300Fax: 856-234-3310Email:[email protected]


You can also find the form and see all the past

winners at www.thermoformingdivision.com in

the Thermoformer of the Year section.

You can submit nominations and bios at any time

but please keep in mind our deadline for

submissions is no later than December 1st of

each year, so nominations received after that

time will go forward to the next year.


THERMOFORMER OFTHE YEAR 2006

Presented at the September 2006 Thermoforming Conference in Nashville, Tennessee

The Awards Committee is now accepting nominations for the 2006THERMOFORMER OF THE YEAR. Please help us by identifying worthy candidates.This prestigious honor will be awarded to a member of our industry that has madea significant contribution to the Thermoforming Industry in a Technical, Educa-tional, or Management aspect of Thermoforming. Nominees will be evaluatedand voted on by the Thermoforming Board of Directors at the Winter 2006 meet-ing. The deadline for submitting nominations is December 1st, 2005. Please com-plete the form below and include all biographical information.

Person Nominated: _______________________________________ Title: _____________________

Firm or Institution: _________________________________________________________________

Street Address: _____________________________ City, State, Zip: ________________________

Telephone: _________________ Fax: _________________________ E-mail: _________________

Biographical Information:

• Nominee’s Experience in the Thermoforming Industry.

• Nominee’s Education (include degrees, year granted, name and location ofuniversity)

• Prior corporate or academic affiliations (include company and/or institu-tions, title, and approximate dates of affiliations)

• Professional society affiliations

• Professional honors and awards.

• Publications and patents (please attach list).

• Evaluation of the effect of this individual’s achievement on technology andprogress of the plastics industry. (To support nomination, attach substan-tial documentation of these achievements.)

• Other significant accomplishments in the field of plastics.

• Professional achievements in plastics (summarize specific achievements uponwhich this nomination is based on a separate sheet).

Individual Submitting Nomination: _______________________ Title: _____________________

Firm or Institution: _________________________________________________________________

Address: ____________________________________ City, State, Zip: ________________________

Phone: ____________________ Fax: _________________________ E-mail: _________________

Signature: ______________________________________ Date: ____________________ (ALL NOMINATIONS MUST BE SIGNED)

Please submit all nominations to: Hal Gilham,Productive Plastics, 103 West Park Drive

Mt. Laurel, New Jersey 08045

Thermoformers of the Year …1982

William K. McConnell, Jr.McConnell Company

1983E. Bowman Stratton, Jr.

Auto-Vac Corp.

1984Gaylord BrownBrown Machine

1985Robert L. ButzkoThermtrol Corp.

1986George Wiss

Plastofilm Industries

1987Dr. Herman R. OsmersEducator & Consultant

1988Robert Kittridge

Fabri-Kal Corporation

1989Jack Pregont

Prent Corporation

1990Ripley W. GageGage Industries

1991Stanley Rosen

Mold Systems Corp.

1992Samuel ShapiroMaryland Cup

Sweetheart Plastics

1993John Grundy

Profile Plastics

1994R. Lewis Blanchard

Dow Chemical

1995James L. Blin

Triangle Plastics

1996John Griep

Portage Casting & Mold

1997John S. Hopple, Hopple Plastics

1998Lyle Shuert, Shuert Industries

1999Art Buckel

McConnell Company

2000Dr. James Throne

Sherwood Technologies

2001Joseph Pregont, Prent Corp.

2002Stephen Sweig, Profile Plastics

2003William Benjamin,

Benjamin Mfg.

2004Steve Hasselbach, CMI Plastics


These sponsors enable us to publish Thermoforming QUARTERLYTHERMOFORMINGDIVISION

BOARD MEETINGSCHEDULE

Hilton MilwaukeeCity Centre

Milwaukee, WisconsinWednesday, September 21, 2005

Executive Committee Arrive

Thursday, September 22, 2005

7:30 a.m. - 8:00 a.m. – Breakfast

8:00 a.m. - 5:00 p.m. – ExecutiveCommittee Meeting, Presidential Suite2432

12:00 noon - 1:00 p.m. – Lunch

1:00 p.m. - 2:00 p.m. – James Alongi,Finance Chair, meets with ExecutiveCommittee

2:30 p.m. - 4:00 p.m. – Technical Chairsmeet with Executive Committee, Room2432

6:00 p.m. - 8:00 p.m. – Board Reception,Presidential Suite 2432

Friday, September 23, 2005HILTON HOTEL

7:30 a.m. - 8:00 a.m. – Breakfast,Kilbourn Room

8:00 a.m. - 10:00 a.m. – MaterialsCommittee, Miller Room

8:00 a.m. - 10:00 a.m. – ProcessingCommittee, Walker Room

8:00 a.m. - 10:00 a.m. – MachineryCommittee, Oak Room

10:00 a.m. - 12:00 noon – ALL OTHERCOMMITTEES, OAK ROOM

12:00 noon - 1:00 p.m. – Lunch,Kilbourn Room

1:00 p.m. - 4:00 p.m. – BOARD OFDIRECTORS’ MEETING, REGENCYBALLROOM

5:00 p.m. – Bus departs from HiltonHotel to Wisconsin Club, Tailgate Partyand Brewers Baseball Game

Saturday, September 24, 2005

8:00 a.m. - 12:00 noon – Board MembersAssist in Parts Competition Setup

6:15 p.m. – Welcome Reception,Convention Center Hall A, 3rd Floor


These sponsors enable us to publish Thermoforming QUARTERLYThese sponsors enable us to publish

ThermoformingQUARTERLY

Visit theSPE

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LEAD TECHNICAL ARTICLE

Enhanced TPO Thermoforming Using HighMelt Strength Polyolefin Elastomers1

BY K.L. WALTON, M.K. LAUGHNER, LAWRENCE J. EFFLER, E.S. GISLER,DUPONT DOW ELASTOMERS LLC, GENEVA, SWITZERLAND

1 This paper, presented at 2005 SPE ANTEC, Boston, has beenedited for publication in TFQ. Any errors or omissions are solelythe responsibility of the technical editor.

AbstractHard TPOs have grown rapidly in the automo-

tive industry because of their favorable cost/per-formance characteristics and injection moldingprocessability. Other plastics processes are now ei-ther currently used or under investigation. Pro-cesses such as blow molding and thermoformingoffer the potential to manufacture large parts withmuch lower tooling costs than injection molding.However, it is well known that conventionalpolypropylene exhibits poor melt strength. Thisdeficiency has limited its use in either large partextrusion blow molding or thermoforming.

Recently, polypropylene producers have intro-duced high melt strength polypropylene into themarket. These polypropylenes have much highermelt strengths than conventional materials. Theyare being promoted for used in hard thermoplasticolefin (TPO) applications requiring high meltstrengths.

However, other components, particularly the im-pact modifiers, can now play important roles in thethermoforming characteristics of hard TPO com-pounds. In a series of experiments, significantchanges in TPO Rheology were observed, depend-ing on the level and type of impact modifier used.The characteristics of ethylene/alpha olefin copoly-mer impact modifiers and their effect on hard TPOthermoforming performance will be discussed.

IntroductionPropylene based compounds continue to success-

fully replace engineering polymers in automotiveexterior and interior applications. The primarydriver for this substitution is raw material cost. A

desire for lower conversion cost has led some TierI suppliers to examine methods of large part manu-facturing other than injection molding. Forexample, it is possible to manufacture similar largeparts using either thermoforming or blow mold-ing that were formally reserved for injection mold-ing. The primary advantage of these conversionprocesses is lower capital, including tooling costs.On the other hand, it is well known that conven-tional polypropylene exhibits poor melt strength(1). The low melt strength stems from the lack ofmelt strain hardening. This deficiency has limitedits use in blow molding. Thus, conventionalpolypropylenes have very narrow processing win-dows for most thermoforming and blow moldingapplications.

Several approaches were attempted to improvepolypropylene (PP) melt strain hardening charac-teristics. For example, high-pressure LDPE wasblended with PP at 15-20% (wt) to yield a PP com-position with some extrusion coating capability (2).The LDPE has long chain branching (LCB), whichcauses the polymer to exhibit melt strain harden-ing, an important attribute in several processes. TheLDPE has some compatibility with the PP and thushas an influence on the melt behavior. This blendapproach has also been extended to thermoformingapplications.

PP manufacturers are now offering alternativesto conventional technology by providing productswith LCB incorporated into the polymer backbone.The LCB structure causes the polymer to exhibitmelt strain hardening, an important attribute forthermoforming. Numerous methods have been de-scribed to incorporate LCBs into PPs (1, 3-5).

Constrained geometry catalyst (CGC) technologyutilizes a proprietary catalyst and solution processbased on transition metal chemistry, with titaniumbeing the most commonly used transition metal.This catalyst technology enables the copolymeriza-


.

(continued on next page)

tion of ethylene with different potential alpha ole-fin comonomers. For example, DuPont DowElastomer’s newest plant manufactures both eth-ylene/1-octene and ethylene/1-butene copolymersusing this catalyst. These copolymers are widelyused as PP impact modifiers because of their elas-tomeric nature, compatibility with PP, and pelletform.

The combination of CGC catalyst and the solu-tion process allows the development of reactor con-ditions, which can be tuned to produce ethylenecopolymers containing LCB 96). By judicious reac-tor control, ethylene alpha olefins (EAOs) with dif-fering levels of LCB are produced (7).

This paper investigates the use of EAOs havinghigh and medium LCB levels in PP as impact modi-fiers. The effects of these impact modifiers on PPthermoforming characteristics are highlighted.

Experimental

Sample Preparation

The three EAO samples in this study were pro-duced in DuPont Dow’s commercial facilities us-ing CGC technologies. Three commerciallyavailable PPs were examined. Selected propertiesare shown in Table 1.

Blend compositions were melt compounded us-ing a Coperion ZSK25 corotating twin screw ex-truder. The compounded pellets were extruded on

a 50 mm Killion extruder equipped with a 610 mmwide EDI sheet die feeding a 600 mm wide DavisStandard three-roll stack having chromed polishedrolls. The die gap was adjusted to yield a 1.1 mmthick sheet. Roll speed was adjusted to minimizeorientation. Tables II - IV (see page 12) show thecompounded samples tested.

Thermoforming

The sheets were tested for thermoformability us-ing a Lamco thermoformer equipped with 12 indi-vidually controlled quartz heaters, top and bottom.And infrared pyrometer was positioned at the bot-tom of the oven to monitor sheet surface tempera-ture. The average power setting was 40% for thetop and 55% for the bottom. Square sheets 56 cm x56 cm were cut and clamped. After reaching thedesired temperature as measured by the oven py-rometer, the sheet was indexed out of the oven,surface temperature was measured via a hand-heldpyrometer, and the sheet was vacuum formed intoa 14.5 cm x 14.5 cm cavity mold with 2.4 cm depth.The sheets were thermoformed over a temperaturerange. The temperature at which complete partthermoforming was achieved in the inside cavitywas called the “minimum temperature.” The tem-perature at which the sheet formed a hole duringvacuum forming was called the “maximum tem-perature.”

Table IPolymers Tested

Grade Type Comonomer Melt Melting DensityViscosity Temp. (kg/m3)dg/min (° C)

PP1 PP high LCB impact 1.8a 163 903Copolym.

PP2 Clarified PP none 0.42a 164 905homopolym.

PP3 PP homopolym. none 1.35a 165 905

EB1 EAO hi LCB butene 0.25b 93 901

EB2 EAO med LCB butene 0.28b 48 870

EO1 EAO med LCB octane 1.6b 93 897

ABS1 Extrusion grade terpolym. 1.2c N/A 1040

a = melt flow rate at 230°C, 2.16 kg. wt.b = melt index at 190°C, 2.16 kg. wt.c = melt index at 230°C, 10 kg. wt.N/A = not applicable. ABS has no crystalline melting point


(continued from previous page)

For selected samples, the thermoforming sheetsag was measured as a function of index tempera-ture. A video capture technique was used to obtainthe data.

Physical Properties

Sheet hardness was measured according toASTM D2240. The tensile properties were deter-mined according to ASTM D638. Instrumented dartimpact was measured according to ASTM D3763.Sheet tear strength was measured according toASTM D1004.

Rheological Measurements

Dynamic shear tests were conducted at 190, 210,and 230°C on a Rheometrics dynamic spectrometer

Thermoforming ComparisonSimple Two Component Blends: Figure 3 compares

the thermoforming window of PP2 alone andblended at 10% (wt) with EB1, EB2, and EO1. Asseen, PP2 (unbranched homopolymer PP) exhibitsa very narrow thermoforming window. All of theEAOs improve the PP2’s thermoforming window.The widest thermoforming window is observedwith compound #3 containing 10% EB1. The sheetof compound #4 exhibits localized thin spots dur-ing thermoforming. It is apparent that the incorpo-ration of an EAO with high LCB levels significantly

Table IVFully-Formulated TPOs

Compound A BIngredient wt. % wt. %

PP3 48 44PP1 8 12EB1 24 24Talc 20 20

Antioxidant 0.2 0.2

Table IIIThree-Component TPO Composition, [wt. %]

PP3 PP1 EB150 50 085 0 150 70 300 100 00 85 1570 0 3035 35 30

100 0 0

Table IISimple Two-Component Blends

Compound PP1 PP2 EB1 EB2 EO11 100 0 0 0 02 0 100 0 0 03 90 0 10 0 04 90 0 0 10 05 90 0 0 0 106 0 90 10 0 07 0 90 0 10 0

Figure 1. Tan deltas versus frequency of the tested PPs.

Figure 2. Tan deltas of the tested elastomers in the melt state.

model ARES, with a parallel plate fixture of 25 mmand 2 mm cap setting. A 15% strain level was usedon all samples.

Results and Discussion

Rheological Characteristics

Figure 1 compares the tan deltas of the three PPs.The relatively flat response of the tan delta curveto frequency in Figure 1 infers that LCB is presentin PP1. As seen in Figure 2, the relative flatness ofthe tan delta curve for EB1 infers a significantlyhigher LCB level than either EB2 of EO1.


Figure 3. Effect of impact modifier on PP2 thermoforming window.

improves the thermoforming window of standardPP homopolymers by 25°C.

Figure 4 compares the thermoforming windowof PP1 alone and blended at 10% (wt) EB1 and EB2.

Note that a much higher temperature is requiredto thermoform the PP1-based compounds. Sheetsbased on PP1 exhibit very little sag, indicating sig-nificantly higher melt strength than PP2-basedsheets. However, little change in the breadth of thethermoforming window is observed. Further, atelevated temperature, hole formation readily oc-curs. Also, during thermoforming, high levels ofsheet “nerve” are observed. No thermoformingbenefit is observed by adding EB1 to PP1. How-ever, by adding EB2 to PP1, the thermoformingwindow increased by 30°C. With EB2 present, thesheet deformed more readily at higher tempera-tures with no rupture. Perhaps the addition of alower LCB EAO with reduced melt elasticity im-proves the melt extensibility of a composition hav-ing a branched PP.

Simple Three-Component Blends: It has been pre-viously reported that blends of branched PP withstandard PP homopolymers and a branched impactmodifier yielded compositions with optimum per-formance for thermoforming (8). A Three-comp-onent mixture design was formulated to determine

the effect of standard PP, branched PP, andbranched EB blends on thermoforming sheet sag.The experimental compositions are shown in TableIII. ABS1 was used for benchmark comparison. Fig-ure 5 compares the sheet sag verses temperature ofselected compounds from this study. A wide rangeof sheet sag characteristics is seen for these com-pounds.

Figure 5. Three-component TPO thermoforming sage range.

As expected, standard PP3 alone sagged most.On the other hand, pure PP3 exhibited low sag. Thelowest sag observed was with blends of PP1, PP3,and EB1. The ABS1 sag characteristic is shown inthe the middle of the sag curves.

Fully Formulated TPOs: Based on the three comp-onent results, two optimize TPO compounds wereevaluated and compared with ABS1. Table IV de-scribes these two TPO compounds. Figure 6 showsthe temperature-dependent sag characteristics ofthese two compound. As seen, The sag character-istics of both compounds match the ABS1 sheet sagcharacteristics reasonably well, with the TPO Bcompound having the better match of the two. Thesag characteristics and sag time of TPO B closelymatches that of ABS1 at 210°C.

Figure 6. Thermoforming sag comparison, TPO-A, TPO-B, andABS1.


Figure 4. Effect of impact modifier on PP1 thermoforming window.



Physical PropertiesFigures 7 and 8 are radar plots comparing the ef-

fects of adding 10% (wt) impact modifer on the physi-cal properties of PP. As shown in Figure 7, all impactmodifiers improve the impact strength of PP1 at 0°C.

pact modifier compounded into the PP during itsmanufacture. Additional impact modifier had littleeffect on haze.

ConclusionsThe thermoforming characteristics of standard PPs

can be significantly improved with the addition ofnewly developed LCB impact modifiers. Higher crys-talline impact modifiers match the refractive indexof PP and yield compositions with good clarity. Lowercrystalline impact modifiers yield optimum impactmodifications.

The branched PP examined in this study exhibiteda high level of melt strength, but low melt extensibil-ity. The addition of an impact modifier with low lev-els of LCB improved the melt extensibility andthermoforming window of this PP.

TPOs containing optimized levels of standard PP,branched PP, and branched EAO yieldthermoforming sag characteristics similar to athermoforming grade ABS.

AcknowledgmentsThe authors thank Doug Waszneciak for his help

in manufacturing the sheets and thank the testing labpersonnel of DuPont Dow Elastomers for providingphysical property data on the various polymers andformulated compounds.

References1. Tau, L., et al, US Patent 6,593,005, assigned to The Dow

Chemical Company, July 2003.2. Beren, J.R., Phillips, E.M., Reginister, L., and Travernier,

M., “Polyolefins for Extrusion Coating: Trends and Limi-tations,” Presented at TPPI, Dusseldorf, 1995.

3. Weng, W., Hu, W., and Dekmezian, A.H., “Structure andProperty of Long Chain Branched Isotactic Polypropy-lene,” Presented at 226th ACS National Meeting, NewYork, 2003.

4. Oliver, D., Michel, J., Dupire, J., European Patent Appli-cation EP 2002-77723, assigned to Atofina Research SA,2002.

5. DeMaoi, V., and Dong, D., “The Effect of Chain on MeltStrength of Polypropylene and Polyethylene,” presentedat SPE ANTEC, Toronto, 1997.

6. Laughner, M., Parikh, D., and Walton, K., “New Devel-opments in Metallocene Ethylene Elastomers for Auto-motive Applications,” presented at the SPE GlobalPolyolefins Conference, Houston, 2001.

7. Lai, S., et al., US Patent 5,272,236, assigned to The DowChemical Company, 1993.2

8. DeMaio, V.V., Dong, D., and Gupta, A., “Using BranchedPolypropylene as a Melt Strength Modifier - Improvementin Sheet Sag Resistance,” presented at SPE ANTEC,Orlando, 2000. ■

Figure 7. Radar plot of PP2 properties with and without 10% (wt.)impact modifier.

However, the low crystallinity EB2 is a more efficientimpact modifier. Because the refractive index of EB1and EO1 matches that of PP2, sheets are quite clear.As a result of the comonomer content, the crystalstructures of these two EAOs match the refractiveindex of PP. On the other hand, the refractive indexof low crystallinity EB2 does not match those of otherEAOs. As a result, sheet based on EB2 is hazier. Highclarity impact-modified thermoformable TPOs mayprove useful in translucent applications or in partswhere color depth is important.

Figure 8 compares the effect of adding impactmodifier to PP1. The DSC melting point indicates thatthe product is not a random copolymer. On the otherhand, the 0°C impact value of PP1 is higher than thatfor a standard homopolymers. This suggests that itcontains an impact modifier. Additional modifier haslittle effect on its impact strength. It is evident thatPP2 is not designed for transparent applications. Thehaze of PP2 alone is quite high. It is likely that thehaze is partially the result of a low crystallinity im-

Figure 8. Radar plot of PP1 properties with and without 10% (wt.)impact modifier.


Collaborative and Methodical Product DevelopmentReduces Time From Concept to Production

INDUSTRY PRACTICE

BY ERIC HAUSSERMAN, PREMIER MATERIAL CONCEPTS, FINDLAY, OHIO

The most effective product development initiative en-sures that all parties involved have input … from the

resin supplier, all the way through to the end-user sinceso many factors must be taken into consideration whendeciding on a material or a finish.

First and foremost the function of the finished productmust be taken into account. How is the product going tobe installed? What elements is the product going to face?What is the expectation as far as life of the product? Thesecould include: UV stability, chemical resistance, co-effi-cient of friction, fire rating, etc. For example, PMC devel-oped a Thermo Plastic Elastomer (TPE) insert for ahousehold step stool. The design of this product coveredmany of the factors mentioned above. A product was cre-ated that achieved a high co-efficient of friction, so thatthe user would not slip off the stool when in use. It alsowas chemical resistant, as step stools are often used aroundcleaning supplies. If not the insert could become easilyand quickly degraded.

Next we took into consideration the processes that thematerial would go through as it was manufactured into afinished product. What kind of temperature is the prod-uct going to see in secondary processes? Is any pressuregoing to be applied to the sheet in secondary processes?Could the material be scratched as it goes through sec-ondary processes? These include: Thermoforming, die cut-ting, lamination, injection molding, etc.

Consideration of these factors above was critical for thisproject. First we discovered that the material would gothrough a secondary die cutting operation. So the mate-rial designed had a very clean trim permitting it to be diecut very efficiently. Next the insert was to be placed in-side an injection mold. The material we developed with-stood a very high temperature, did not “bleed,” andmaintained a very crisp, clean edge, when the molten plas-tic was shot behind it.

Creating this product was a very collaborative effort.There was involvement from the resin supplier, the sheetextruder, the die-cutter, the manufacturer of the footstool,and of course feedback from potential end-users. Theproduct was developed, qualified, put through all of thespecified testing, and we were able to go from concept toproduction in 45 days.

We also believe using a “Stage Gate” approach enhancedour success. It made sure everyone knew the objectives,whether we have met our objectives, and that the properresources were being allocated.

The following steps are an example of an effective StageGate process:

1. Investigation/quote phasea. Product criteriab. Product designc. Manufacturing process(s) designd. Quotation

2. Sample/Prototype phasea. List requirementsb. Sample runc. Testingd. Submissione. Customer feedback

3. Approved product/proceed to productiona. Forecastb. Finalization of manufacturing processes/

equipmentc. Vendor releasesd. Quality plan

4. Post Production analysisa. Continuous improvement opportunitiesb. Other product/market applications

Product development, and determining the right finishfor your thermoplastic product, is a very complex pro-cess. If the proper steps are not followed, this can be avery expensive and inefficient process. If you involve ev-eryone, follow the right steps, you can “get the right fin-ish” for your thermoplastic materials and reduce thenumber of days necessary for the development of yourproduct.

***************************Premier Material Concepts (PMC), is a custom manufacturerof TPE, ABS, HIPS, PP and acrylics for thermoforming, POPdisplay material, converters and custom fabricators. PMC, adivision of Rowmark, Inc., serves diverse industries includingmarine, industrial, aerospace, government, agriculture, auto-motive, displays, signage, electrical and furniture. For addi-tional information about Premier Material Concepts (PMC)visit their Worldwide Web at www.buypmc.com.


Proper Colleting and Collet Maintenancein CNC Routing of Plastic1,2

INDUSTRY PRACTICE

BY VAN NISER, ONSRUD CUTTER, LIBERTYVILLE, ILLINOIS

IntroductionRigidity is a key factor in the routing of plastic

material. The problems associated with rigidity in-volve the part as well as the machine. Parts mustbe held solidly with established fixturing tech-niques, and the machine must be appropriatelymaintained to insure the cutting tool is followingthe proper tool path in a rigid and concentric fash-ion. One of the elements that aids in this wholeprocess lies in the area of proper colleting of therouter bit and the ongoing maintenance procedureassociated with router collets.

Types of ColletsThe half-grip and full-grip collets are the two

basic types found in CNC routers. Half-grip colletsare identified by slits running from the bottom ormouth of the collet toward the top for about 80%of the collet length. These collets are often counter-bored at the top, so that the shank of the tool doesnot contact the entire length of the collet. The forceholding the collet is primarily generated at themouth of the collet, and proves ideal in situationswhere the shanks of the router tools are not longenough to fill the entire collet, Figure 1.

The full-grip collet is identified by slits runningfrom both ends of the collet, which creates specificcollet sections. Full-grip type collets allow forsqueezing pressure to be exerted over the entirelength of the collet, Figure 2.

1This article appeared in Plastic Distributor & Fabricator, Nov/Dec2004, and is reprinted with permission of David Whelan, Editor/Publisher. For subscription information, please contactwww.plasticsmag.com. The article has been edited by TFQ Tech-nical Editor, who is responsible for any alteration in content or in-tent.2 Although the article addresses plastic trimming issues, the infor-mation is directly applicable to pattern makers and craftsmen work-ing in other materials such as wood.

Figure 1. Half-Grip Collets.

Figure 2. Full-Grip Collets.

Proper ColletingThe proper method of colleting a router bit in

the full grip collet is to fill at least 80% of the depthof the collet. This allows the tool to be equally dis-tributed on all sections of the collet and providesan environment where the tool runs in a true circle


Figure 5. Collet Examples.


or concentrically. Without concentricity, the finishof the plastic will be adversely affected and toolfailure can occur. There are situations where the80% rule cannot be maintained because of inad-equate shank length or extreme reach problems.Consequently, it becomes necessary to fill the voidin the top of the collet with a filler or collet life plug.This is a practical solution to avoid collapsing ofthe collet, which may result from not following the80% rule, Figure 3.

Figure 3. Proper Tool Colleting.

In all router bits, there is an area known as theflute fadeout section of the tool. This is formedwhen the grinding wheel utilized in the manufac-turing of the tool exits the work piece. In order toproperly collet a router bit, the mouth or bottom ofthe collet must contact the router bit slightly abovethe flute fadeout. Over-colleting or allowing theflute fadeout portion to extend inside the collet candamage the collet. This is a common cause of toolbreakage, Figure 4.

Figure 4. Incorrect Tool Colleting.

Collet MaintenanceRouter bits and collets are expected to operate

accurately in a work environment inundated withheat and grime. Plastic chips formed by the cut-ting action of the router bit carry with them resinsthat migrate through the slits of the collets and ad-here to the inside of this closely toleranced mecha-nism. The resin build-up usually concentratesnearest the mouth of the collet. At this point, thetool is no longer being equally gripped, causing aloss in concentricity and tool run-out. Once again,the lack of a router tool running in a true circle af-fects the finish of the part and may cause the ulti-mate demise of the tool, Figure 5.

Fortunately this problem is easily resolved bycleaning the collets after every tool change. The pro-cedure involves the use of a non-abrasive brass tubebrush applied inside the collet in combination witha cleaner such as Rust Free™. All surfaces inside andoutside the collet, inside the spindle taper, andmatching and mating surfaces of quick-change toolholders, should be thoroughly cleaned and driedbefore being reassembled. Also the collet nut shouldbe cleaned of resin and chip build-up and regularlyreplaced to ensure the integrity of the whole colletsystem, Figure 6.

Figure 6. Full-Grip Collets.



Collet ReplacementCollets are manufactured from spring steel and

regular usage causes a loss of elasticity. Therefore,it becomes necessary to replace collets on a regularinterval as part of an ongoing maintenance pro-gram. With diligent attention to proper collet main-tenance, the average collet should be replaced aboutevery 400-600 hours. Avoiding regular replacementcan lead to brittle collets, which may crack or break,and cause permanent damage to the spindle. Re-

placement of collets is a much more economicalalternative than replacing router bits or expensivespindles.

Rigidity and concentricity are the key elementsin any routing application. The simple process ofproperly colleting router tools, maintaining collets,and replacing them at regular intervals will safe-guard the productivity of the operation and ensurethat the finish of plastic parts is not jeopardized.

For more information on this or other cutterissues, contact Onsrud Cutter, 800 Liberty Drive,Libertyville IL 60048, email: [email protected]. ■

Tsunami Relief – Thermoforming Style!

On December 26, 2004 at approximately 8:00 ama magnitude 9.3 earthquake devastated the

ocean floor off the coast of Northwest Sumatra. Theresulting Tsunami traveled thousands of miles acrossthe Indian Ocean, taking the lives of nearly 300,000people in countries as far apart as Indonesia, theMaldives, Sri Lanka and Somalia.

Early in 2005, the Thermoforming Division startedto investigate a way we could help out. Our thoughtswere to find a truly unique way to make a differ-ence. We looked into some of the more conventionaldisaster relief funds, Unicef, Red Cross andWorldvision. That is when I received a phone callfrom my sister, Barbara McConachie, a registerednurse who has made numerous relief trips to 3rdworld countries. Her group, PRN International, waslooking to send a small group of doctors and nursesover to Sri Lanka to assist with the relief efforts. Thisgroup was experienced in the most efficient way toget in and get busy.

At our winter Board of Directors meeting inFlorida, I submitted a request for a donation to PRNInternational. The request was unanimously ap-proved. On January 28th, 3 doctors and 5 nurses fromBridgeport Hospital left New York for Sri Lanka.Twenty-eight pieces of luggage filled with donatedantibiotics, vaccines, analgesics, skin ointments andbaby formula made the trip as well. Our volunteersworked their way up the northern coast of Sri Lanka(Ampara) and partnered up with healthcare provid-ers from around the world.

During their stay the PRN relief team treated over200 people in 3 different refugee camps on a dailybasis; revisiting these same people every other daytrying to prevent a outbreak of Malaria and Cholera.The physical injuries treated were pneumonia, di-arrhea, fevers, open wounds and cellulitis. Thephysiological wounds were just as bad if not worse;most of the people lost 3 out of 4 family members.Depression and Post Traumatic Stress Syndrome is

rampant. The widespread devastation witnessed bythese workers cannot be put into words. PRN Inter-national and my sister would like to thank theThermoforming Division for their $2,500 donation.The Thermoforming Division would like to thankthe volunteers at PRN International for actually do-ing what most of us just talk about. We would liketo think that in some tiny way, though PRN Interna-tional, D25 made a difference, Thermoforming Style.~ By Mike Sirotnak, Solar Products ■


History of Thermoforming – Part IINDUSTRY PRACTICE

BY STANLEY R. ROSEN, PLASTIMACH CORPORATION, LAS VEGAS, NEVADA

Ed. Note I: The philosopher Santayana said, “Those who cannotremember the past are destined to repeat it.” Stan Rosen is under-taking a prodigious project – identifying the pioneers who laid thefoundations of the industry we know so well. Although shaping ofsheet extends back to pre-history – oil-heated and shaped tortoiseshell and steam-heated and shaped wood, Stan begins the jour-ney in the 1930s. We hope you enjoy the trip!

Ed. Note II: Each year since 1982, the SPE Thermoforming Divi-sion has honored a leader in the thermoforming field. Bow Strattonwas the 1983 Thermoformer of the Year. Bob Butzko was the 1985Thermoformer of the Year. And Stan Rosen, the author of this ar-ticle was the 1991 Thermoformer of the Year. Stan can be reachedat [email protected]. (continued on next page)

Thermoforming Pioneers 1930-1950The development of modern machinery for the

thermoforming industry took place on the shoul-ders of very perceptive pioneers during the years1930-1950. These experimenters did not have themodern tools or hindsight we now possess yet theydeveloped many of the processes we currentlyemploy. Information contained in this article wasabstracted from periodicals, patents, and conver-sations with industry innovators. Some firms dur-ing this period developed proprietary equipmentto thermoform their products and they are name-less at this time.

A great deal of development effort pre-World WarII went into forming airplane acrylic canopies freeof flaws. E. L. Helwig of Rohm and Haas Companyin Philadelphia, an acrylic resin manufacturer, hastwo patents using different techniques which whenmodified can be used today.

Figure 1. Helwig’s patent, filed on 11-27-1938, il-lustrates the forming of a canopy from a pre-heatedsheet of acrylic forming which utilizes a hot fluidunder variable pressure. The mold was watercooled so that sheet surface facing the cavity wouldchill and be hard enough to avoid being marredagainst the mold surface. The inner surface sheetwould be free of blemishes since its contact is withthe hot fluid. This process is similar to a modifiedmethod used today where air pressure forms sheetagainst a temperature- controlled mold producinghigh quality parts.

Figure 1. H. E. Helwig of Rohm and Haas Corp. filed for a patent 11-27-1936 using hot oil pressure for forming acrylic.

Figure 2. Helwig patent filed, on 8-28-1942, de-scribes a male snap-back technique using an oven-heated acrylic sheet which is clamped to the devicewith quick-acting clamps or bolts. Figures 2-1 and2-2 exhibit the use of vacuum to pre-stretch the hotsheet and allowing atmospheric pressure to forcethe cooling plastic to the male cavity. Figures 2-3and 2-4 show air pressure creating a bubble of hotplastic which, after the air is exhausted from the

Figure 2. H. E. Helwig filed for a patent 8-28-1942 using snapbackforming.



chamber, the cooling sheet then conforms to thecavity. The expansion of the surface of the hot sheetbefore forming is used to assist in producing uni-form wall thickness on the finished part. This pro-cess appears to be the first patent in which a malecavity is used in thermoforming.

Figure 3. R. E. Leary of Dupont Corp., patent filed12-27-1940, illustrates vacuum forming using twomethods of controlling a radiant heat source toachieve a uniform wall thickness.

1. This heater assembly can be raised or loweredrelative to the plastic sheet line. Moving a heatsource away from or toward the sheet is a power-ful method of heat control. The distance of a radi-ant source to its receptor is not a linear functionand a small movement can create big differencesin temperature distribution across a sheet surface.

2. Each lamp in the heater assembly is individu-ally controlled so that the heating pattern can bezoned to promote a uniform temperature distribu-tion across the sheet. This patent suggests the useof radiant heating at the forming site rather thanpreheating the sheets in an oven and later trans-porting them to a mold.

Figure 4. J. J. Braund, patent filed on 2-17-1936,is not a plastics fabricating patent but it has an in-teresting concept. Braund in the early 1930s startedto develop a process to produce inexpensive three-

Figure 4. J. J. Braund filed for a patent 2-17-1936 for a relief mapduplicating machine.

dimensional relief maps for the U.S. Coast and Geo-logical Survey. A relief map sheet is distortionprinted with each color referring to a specific el-evation. When formed, the map might use greenfor sea level at the sheet line and white for the tipsof the mountains in the deepest part of the mold.This technique locates a pre-printed sheet of duc-tile metal facing a female mold mounted above theblank. The back face of the sheet is sealed to a shal-low box and the whole assembly is locked in a pow-erful clamp frame. Hydraulic oil under pressure is

Figure 5. J. T. Braund filed for a patent 9-24-1946 for a relief matvacuum former using convection heat..

Figure 3. R. E. Leary of DuPont Corp. filed for a patent 12-27-1940for a vacuum forming apparatus.


pumped into the box, forcing the metal sheet to flowinto the mold. If the date of the above patent was1946 instead of 1936, Braund could have chosen tosubstitute a plastic sheet instead of metal and mighthave used air instead of oil pressure.

Figure 5. J. J. Braund filed a patent on 9-24-1946,which describes a system for vacuum forming plas-tic relief maps similar to his earlier 1936 metal form-ing methods. This sheet heating system is analo-gous to R. E. Leary’s oven, except the heater pro-vides convection heat transfer rather than radiantheating. The top fan creates an air flow through the

heated sheet frame is moved manually from stepto step. Wiley has developed four similar varia-tions of this technique. (Only one is illustrated asfollows:)

Figure 6-1 is a steam heating chamber. In Figure6-2, a shallow female mold and sheet is pressure-formed using steam and its wall thickness is at aminimum at (20a) and thickest at (20b). In Figure6-3, the sheet is steam-reheated with male cavity(31) lying in the shallow form to prevent distor-tion. When the sheet reaches forming temperaturethe steam is exhausted and the cavity (31) is ex-tended to final depth while atmospheric air pres-sure forces the sheet against the cavity. The malecavity draws material from the upper side wall(20d) and very little from the tip (20a) which re-sults in a fairly uniform product, Figure 6-4. ■

References

J. H. DuBois, Plastics History USA, Cahners Publish-ing Co., Inc., 1972.

J. J. Braund, US Patent 2,066,555, filed 2-17-1936.E. L. Helwig, US Patent 2,142,445, filed 11-27-1936.C. B. Strauch, US Patent 2,229,613, filed 11-22-1938.R. E. Leary, US Patent 2,377,946, filed 12-27-1940.G. W. Borkland, US Patent 2,347,806, filed 10-2-1941.E. L. Helwig, US Patent 2,365,637, filed 8-28-1942.F. E. Wiley, US Patent 2,468,697, filed 6-1-1944.J. J. Braund, US Patent 2,493,439, filed 9-24-1946.G. W. Borkland, US Patent 2,559,705, filed 7-8-1947.Phone conversation with Jim Phohl, Plaxall Corp., Long

Island City, NY, Dec. 2004.Phone conversation with Steve Hasselbach, CMI Plas-

tics Corp., Cranbury, NJ, Dec. 2004.SPI (NPE now), archives from Hagley Museum and

Library, Wilmington, DE, for exhibitors 1950, 1952.Modern Plastics and Modern Plastics Magazine, issues

1950-1953.Army Map Service, Relief Map Division, Corps. of En-

gineers, Washington, DC.

Figure 6. F. E. Wiley of Plax Corp. filed for a patent 6-1-1944 for amethod of deep drawing plastic sheets.

bank of heat lamps which increases the air tempera-ture within the hood and heats the plastic to form-ing temperature. Braund claims this method cre-ates a very uniform sheet temperature for accurateregistration of pre-printed sheet to vacuum form-ing mold.

Figure 6. F. E. Wiley of Plax Corp., Hartford, Con-necticut, filed for a patent on 6-1-1944. It is con-cerned with forming techniques which produce auniform wall thickness on deep drawn parts. Thissystem is a three-step process in which the sheet ispre-heated, and in the second operation it is drawnto a shallow depth in a female cavity. A third op-eration draws the sheet to the deeper finished sizeon the male cavity. The heating medium is steam,which raises the sheet to forming temperature inall the steps and the clamp which holds the pre-

PART II WILL FOLLOWIN THE NEXT

THERMOFORMINGQUARTERLY


Understanding How a Sheet Stretches1

BY JIM THRONE, SHERWOOD TECHNOLOGIES, INC., DUNEDIN, FL

THERMOFORMING101

We began our discussion ofpart design by reviewing

why we might not want to quoteon a job. But let’s suppose that wedid quote on the job. And we got it.Now what?

Forming into a Mold v.Forming onto a Mold

In the not-so-politically-correctjargon of the day, if we form into amold cavity, the mold is called a“female cavity.” A better PC2 phraseis “negative mold.” If we form ontoa mold, the mold is called a “malemold.” The proper PC phrase is“positive mold.” Is there a differ-ence in forming “into” v. forming“onto”? Of course. Let’s considerfor the moment, forming a verysimple truncated cone. If we use amold cavity, the sheet first drapesinto the open cavity, then stretchesinto the cavity with the sheet pro-gressively laying on the mold sur-face. Keep in mind that the sheetthat contacts the mold surface usu-ally doesn’t stretch any further. Asa result, the sheet that is free of themold becomes thinner and thinneras it is stretched to the bottom ofthe mold. The wall of the resultingpart is thickest at the rim and thin-nest at the bottom. The thinnest re-gion of the part is in the cornerwhere the wall meets the bottom.We can show arithmetically that if

the wall makes a 60-degree anglewith the horizontal rim, the wallthickness decreases linearly fromthe rim to the corner. If the wallmakes a 90-degree angle [thinksoup can], the wall thickness de-creases exponentially.

Now consider using a truncatedcone male mold. The sheet firsttouches the mold at the bottom ofthe part being formed. As the moldpushes into the sheet, the sheetstretches between the clamp andthe bottom of the mold. If the sheetdoesn’t touch the sides of the molduntil the mold is completely im-mersed in the sheet, the sheet thick-ness is usually quite uniform. If thesheet progressively touches thesides of the mold as the mold is be-ing pushed into the sheet, the wallof the resulting part will be thick-est at the bottom and thinnest at therim.

Does it make a differencewhether we form into a cavity orover a mold? If part performanceis important, probably not, if thepart draw ratio3 is very low [thinkpicnic plate or aircraft enginecover]. As the draw ratio increases,however, the thinnest sections ofthe part begin to control the perfor-mance of the part. Several other fac-tors can influence our decision,such as:

• Is it easier to prestretch thesheet when forming into a cav-ity or over a mold?

• Is it easier to machine a cavityor a male mold?

• Is the rim thickness important,as in the case of thin-gauge con-tainers?

• And does the customer needthe inside or the outside of thepart to be the positive surface4?

Usually – but not always – me-chanical plugs are more effective instretching sheet into a cavity, fe-male molds are easier to fabricatethan male molds, and rim thicknessis better controlled with femalemolds. We’ll revisit some of thesefactors later.

Forming “Up” v. Forming“Down”

What does this mean? If the moldis placed above the sheet, the moldis immersed in the sheet and thepart is formed up onto or into thetool. If the mold is placed below thesheet, the sheet sags into or onto themold and the part is formed downonto or into the tool. Why is this anissue? In thin-gauge thermo-form-ing, forming up has advantageswith female molds. Gravity helpswhen releasing parts from multi-cavity tooling. And the parts areproperly oriented for in-line trim-ming. Having said that, keep inmind that it is easier to mechani-cally prestretch the sheet into fe-

1 This is the third in a series that focuseson part design.2 PC. Politically correct.3 We discuss draw ratio in the next lesson.4 By “positive surface,” we mean that sur-face that the customer considers to be themore important one. Usually the surfaceagainst the mold is considered the posi-tive surface, but not always.5 Efficacious: Producing or capable of pro-ducing a desired effect.


These sponsors enable us to publish Thermoforming QUARTERLYmale cavities if the molds are be-low the sheet.

Although the mold weight mayprevent mounting the mold overthe sheet in heavy-gauge forming,there are some advantages here too.For example, when a male mold ismounted over the sheet plane,sheet sag acts to prestretch the sheetprior to the mold immersion. Thesheet is formed down for mostheavy-gauge forming into femalemolds. Again, sheet sag acts toprestretch the sheet prior to form-ing. And certainly, it is easier to ac-tivate and maintain mechanicalplugs if they reside above the sheetrather than below.

Mating PartsIt should be apparent that the

part side against the mold main-tains a more accurate dimensionthan the other side. The mold sideis chosen whenever the part is tomate with another dimensionedpart. For example, for an integral-lid container to be liquid tight, theoutside of one half must mate withthe inside of the other. This mayrequire that one half is formed intoa female mold while the other isformed on a male tool.

An ObservationWhen quoting on a job, it is al-

ways advisable to keep in mind thecapability of your equipment toform the part in the most effica-cious5 and least costly manner. Ifyou can’t form up, don’t quote ona job that is best produced in thisfashion. The more tortuous the pathto perfect parts, the greater the de-gree of difficulty. And surely thegreater the chance for qualityissues. ■

Keywords: positive mold, malemold, negative mold, female mold,draw ratio, forming up, formingdown, sag


BOOK REVIEW

G. L. Beall, The Evolution of Plasticsin America (As Seen Through theNational Plastics Expositions), Plas-tics Historical Society Occasional Pa-per No. 1, 1 Carlton House Terrace,London SW1Y 5DB, United Kingdom,26 pdf pages when printed,[email protected], ~$18.00.

It is fitting that Beall’s latest effort(1) is on the history of plastics as

viewed from the exhibits seen atNPEs and (2) is on a plastic CD-ROM. It is also appropriate that inthis issue, we feature the first part ofStan Rosen’s review of the history ofthermoforming in the IndustrialPractice column. The first NPE wassponsored solely by SPI and washeld in New York City in 1946. Thepublic was invited to the inauguralExposition and the public came –87,000 – an attendance record thatwas not surpassed until 2000! Ofcourse, after the first NPE, the con-ferences were ostensibly closed to allbut members of the plastics industry.

Even though the public viewedplastics as wondrous things in 1946,it seemed that the industry did notreally begin to believe in itself untilthe late 1970s. Attendance appearedto plateau below 40,000 during theintervening years. The attendance in1982, for example, was only 41,000.Attendees in those intervening yearswould have seen the shift from cel-lulosics and phenolics to polyolefinsand urethanes, from a dominance ofcustom molders to the dominance ofmaterial suppliers and major ma-chinery builders, from just over a bil-lion pounds of plastic consumed ayear to more than 40 billion poundsof the stuff. The attendees wouldhave seen a 42-pound compressionmolded television cabinet,Monsanto’s plastic “House of the Fu-ture,” the newly-invented screw in-

1 The reviewer spent many months work-ing on both of these projects, saw themexhibited at NPE, and then watched thefirst fail FDA trials and the second fail eco-nomically.



jection molding machine, the blow-molded plastic milk bottle, the nitrilebarrier carbonated beverage bottle,Coors molding-with-rotation (MWR)beer can1, the Weyerhauser 714 com-posite can1, pink flamingos, and thefollowing litany of new plastics –LLDPE, rigid PVC, PP, EVA, ABS,mPPO (Noryl), continuous castacrylic, ionomers, PPS, and PET. Andif you were a collector, you wouldhave tried to take home hula hoops,swimming pool noodles, and PP gar-den chairs, among other attractivegive-aways.

This is a fascinating trip downmemory lane for many of us. Beall’sfirst show was in 1958 in Chicago;mine was in 1966 in New York City.And I’m sure that both he and I havemade the effort to go to every onesince. I, like Beall, remember both theexcitement of the new ideas and theglitz and glamour of the exhibits.Gone are the days when exhibitorsattracted us to their booths withcomely lasses in very short skirts, ortickets to local shows (particularly inNYC), or fancy gentlemen’s after-hours clubs where libationsabounded.

Sometimes in the grim reality of to-day, we need to reflect on anothertime – not as intense, not as throat-cutting – when new ideas were notkept as secrets but were touted asrepresenting the genius of our indus-try, daring the competition to betterthem.

Take time to seek out this CD-ROM. It’s worth the time and effort.And if you weren’t around for thisera, read it and pretend you were.Five books out of five.

~ Jim Throne


Roger Fox David A. J. Morgese

(630) 653-2200

www.foxmor.com

These sponsors enable us to publish



BY STEVE HASSELBACH, COUNCILOR

Council Report …

Atlanta, Georgia


ANTECRegistration at ANTEC was 2,658 (in-cluding participants in the seminars.)A total of 168 registrants attended 19Society seminars.

Incoming President Len Czuba’sSPE mantra is “Connect, Collaborate,Compete!”From the Council Floor – Rebates:

The Council discussed the disposi-tion of rebates and accepted the pro-posal drafted by a special subcommit-tee chaired by Bill O’Connell. Mostchanges to the rebates will take effectin 2007 with the one exception that re-bates in 2006, while based on the priorsystem, will be paid quarterly.

The main differences between theold and new systems are as follows:• Budgeting total rebate dollars – Forexample, if Council budgets rebates at$350,000 and the actual calculationcomes to $315,000, every group wouldreceive 111% of their calculated rebate.Likewise if rebates are budgeted at$350,000 and the actual calculationcomes to $390,000, every group wouldreceive 90% of their rebates. Further-more, rebates will be paid quarterly inthe same year they’re budgeted. Thisprovides Council and SPE with acouple of important advantages. First,spreading the rebate payments outhelps with cash flow management.Second, paying them as part of a bud-get in the same year allows Council tomake decisions about rebates closer tothe time actual rebates will be paid,helping with balancing the budget. Inthe event there are catastrophic diffi-culties, Council has the flexibility toreduce the total rebate amount as italso reduces spending in other areas.Likewise, in times of plenty, Councilwould have the flexibility to distributemore funds to SPE groups.

• Paying rebates quarterly – As men-tioned above, this helps tremendouslywith cash management and will be ini-tiated in 2006 (so rebate payments in2006 will be based strictly on the oldcalculation which is based on member-ship as of 12/31/05, and will be dis-tributed quarterly).• Making the 3 changes to the calcula-tion – These are some minor “commonsense” changes that do not greatlychange the individual amounts. Thechanges are too detailed to presenthere, but please refer to the proposalssent to you prior to the Council meet-ing if you want to review them. Again,these changes will not be implementeduntil 2007.• Paying rebates only for dues payingmembers – In the past, folks who paidno dues (unemployed members, dis-tinguished members, etc.) were stillincluded in the rebate calculations. Thepool of these folks is small, especiallywhen distributed across all of ourgroups.

• Dropping the rebate for the seldom-collected initiation fee – SPE’s initia-tion fee is more often dropped as partof a promotional incentive for newmembers. Since SPE does not collectthese funds, the new system will takethe small amount that was being dis-tributed to groups out of the calcula-tion. Again, no individual group isgoing to be materially affected by thischange.• Tiering Division rebates – Under theold system, Division rebates were nottiered the way Section rebates were.This makes the two systems more par-allel.• Having performance criteria for re-bates – This is not entirely new. Thecurrent system requires a Board of Di-rectors and the submission of the re-quired financial statements. The threeitems below are new, and the idea hereis to monitor how groups are servingmembers, and give the Sections/Divi-sions Committees a heads up on any


These sponsors enable us to publish Thermoforming QUARTERLYgroup that is failing to provide thesebasic requirements so we can work to-gether to get things on track.

– No rebates for sections and divi-sions whose council seat has beendeclared vacant by Council (non-attendance for 3 consecutiveCouncil meetings)

– Requiring communication withmembers (demonstrate regularcommunications to members)

– Having a plan (helps to demon-strate that activities are ongoing)

For a full copy of the proposal, go tothe SPE Leadership page at: http://www.4spe.org/communities/leader-ship/0505/materials.php.

New ChartersThe Council approved the charter of

the Flexible Packaging Division. Twonew SIG’s were presented to Council:Nanotechnology and Micromolding. Astudent chapter was established at theUniversity of Mississippi.

Awards & RecognitionsIn addition to the recognition of the

retiring administration, two additionalawards were given out. The MichaelCappelletti Excellence Award wasgiven to Bill O’Connell and the JamesToner Service Excellence Award wasgiven to Tobi Gebauer.

Outgoing President Karen Winklerthanked her Executive Committee fortheir hard work. Incoming PresidentLen Czuba introduced his ExecutiveCommittee. New Executive Commit-tee Vice-Presidents are: RussellBroome, Héctor Dilán, Lance Neward,and William Smith. Paul Anderson isthe 2005-2006 Treasurer and JohnSzymankiewicz is the 2005-2006 Sec-retary.

PresentationsComposites Division – $1,500 HaroldGiles Scholarship; $1,000 FoundationScholarship program

Mold Making & Mold Design – $1,000Student Author Travel Fund

Detroit Section – $2,000 Essay contest;$2,500 International Education Awardin honor of Fred Schwab

$5,000 Robert Dailey Scholarship

Color & Appearance Division – $1,000Donation to the SPE Foundation

■


September 24-27, 2005

GET READY TOSOAR AT THE

15th AnnualThermoforming

Conference

Midwest Airlines ConventionCenter

Milwaukee, Wisconsin


We need

your

continued

support

and

your

efforts

on

membership

recruitment!!



Help SponsorThermoforming®

Q U A R T E R L Y

ONE YR. SPONSORSHIPS

**Please note the increase in sponsorshiprates. This is the first increase since the

inception of the Thermoforming Quarterlyin 1981. We appreciate your continued

support of our award winning publication.

Patron - $625(Includes 2.25" x 1.25" notice)

Benefactor - $2,000(Includes 4.75" x 3" notice)

Questions?Please Contact:Laura PichonEx-Tech Plastics

815/678-2131 Ext. [email protected]

We Appreciate Your Support!

From The EditorThermoforming Quarterlywelcomes letters from itsreaders. All letters are subjectto editing for clarity and spaceand must be signed. Send to:Mail Bag, ThermoformingQuarterly, P. O. Box 471,Lindale, Georgia 30147-1027,fax 706/295-4276 or e-mail to:[email protected].


Forming

Thermoformers, have

you discovered a

forming tip that you

are willing to share

with your fellow

formers?

A time saver?

Or a cost saver?

Or something that

will save wear and

tear on your machine?

Or your employees?

Then the

Just send Jim Throne a fax at727-734-5081, outlining yourtip in less than a couplehundred words. You caninclude drawings, sketches,whatever. Thanks!

column

is for you!

TIPS


YOU ASKED

• • •WE

LISTENED• • •

Due to the many surveys re-

questing that we change

the dates of the annual

Thermoforming Confer-

ence, the Board has lis-

tened and beginning in

2006, we are pleased to an-

nounce the new dates.

Sunday,September 17

throughWednesday,

September 20,2006

Renaissance NashvilleHotel & Nashville

Convention Center

General Chairman:

Martin Stephenson

Placon Corporation

Phone: 608-275-7215

E-Mail:

[email protected]

Technical Chairman:

Mike Lowery

Premier Plastics

Phone: 414-423-5940 Ext. 102

E-Mail:

[email protected]



MEMBERSHIPAPPLICATION

®



TIM WELDONGeneral Manager

(989) 793-8881Fax (989) 793-8888

Email: [email protected]

These sponsors enable us to publish


1305 Lincoln Avenue, Holland, MI 49423PH (800) 833-1305 / FX (800) 832-5536

www.allenx.com

ABS ABSFR PCABSHIPS HIPSFR GELOYCENTREX LURAN NORYL

SOLARKOTE

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When it comes to answering yourneed for quality thermoform tooling,you can’t find a better sourcethan Producto.

• Complete turnkey service

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• Deliveries to suit your schedules

• Mold beds up to 70" x 120"

• Engineering design using the latestCAD systems and programmingtechnologies

• Gun drilling services andTemperature Control Plates

• Adjustable Pressure Boxes

• Die sets, punches and dies, springs,pins & bushings and a full line ofquality accessory items

Producto Corporation800 Union Ave., Bridgeport, CT 06607

(203) 367-8675FAX: (203) 368-2597


P R O D U C T S / I N C

p l a s t i c s. . . . . . . . .

RAY™

The Experts inThermoforming

1700 Chablis AvenueOntario, CA 91761

909/390-9906800/423-7859

FAX 909/390-9896

www.rayplastics.com

Brian RayVice President/

General Manager

CUSTOM CUT SHEET & ROLL FED MACHINERYOVEN, CONTROL & INDEX RETROFIT KITSPATENTED ADJUSTABLE CLAMP FRAMES

3031 GUERNSEY ROAD, BEAVERTON, MIPH: 989-435-9071 FAX: 989-435-3940

Email: [email protected]

These sponsors enable us to publish Thermoforming QUARTERLYThese sponsors enable us to publish


ARES … CNCMACHININGCENTERS FORMACHININGPLASTIC ANDCOMPOSITEMATERIALS

CMS NORTH AMERICA, INC.Grand Rapids, MI800.225.5267

Visit us on the web at:www.cmsna.comwww.cms.itor email us [email protected]

President

[email protected]

Paul Lapointe

Standex Engraving Group5901 Lewis Rd.

Sandston, VA 23150

Ph: 804/236-3065Fax: 804/226-3462


INDEX OF SPONSORS


ADVANCED VENTURES INTECHNOLOGY, INC. ................. 26

ALLEN EXTRUDERS .................... 34

AMERICAN CATALYTICTECHNOLOGIES......................... 8

ARISTECH ACRYLICS .................. 23

ALTUGLAS INTERNATIONAL ....... 24

BROWN MACHINE ....................... 31

CMS NORTH AMERICA ................ 35

CMT MATERIALS, INC. ................. 34

EDWARD D. SEGEN & CO. .......... 32

LAND INSTRUMENTS .................... 9

LANXESS ...................................... 27

LYLE ................................................ 5

MAAC MACHINERY ...................... 35

McCLARIN PLASTICS................... 34

McCONNELL CO. ............................ 9

MILLER MOLD CO. ....................... 34

MODERN MACHINERY ................ 35

NEW CASTLE INDUSTRIES ......... 29

ONSRUD CUTTER........................ 27

PLASTICS CONCEPTS................... 4

PLASTIMACH................................ 31

PORTAGE CASTING & MOLD,INC. .............................................. 9

PREMIER MATERIAL CONCEPTS . 9

PRIMEX PLASTICS ....................... 34

PROCESSING TECHNOLOGIES .. 34

PRODUCTIVE PLASTICS, INC. ...... 9

PRODUCTO CORPORATION ....... 34

PROFILE PLASTICS ....................... 9

PROTHERM .................................. 25

RAY PRODUCTS, INC. .................. 35

RTP ............................................... 31

SELECT PLASTICS....................... 34

SENCORP ..................................... 36

SOLAR PRODUCTS ....................... 1

SPARTECH PLASTICS ................. 35

STANDEX ENGRAVING GROUP .. 35

STOPOL INC. ................................ 24

TEMPCO ELECTRIC ....................... 8

THERMWOOD CORP. ...... Inside BackCover

TOOLING TECHNOLOGIES,LLC ............................................ 23

TPS ............................................... 35

ULTRA-METRIC TOOL CO. ........... 32

WALTON PLASTICS...................... 29

WECO PRODUCTS ...................... 25

WELEX, INC. ................................. 29

ZED INDUSTRIES ......................... 34

ENSINGER/PENN FIBRE .............. 28

FILTRONA EXTRUSION ................ 25

FOXMOR GROUP ......................... 25

FUTURE MOLD CORP. ................. 35

GEISS THERMOFORMING........... 30

GN PLASTICS ............................... 27

IRWIN RESEARCH &DEVELOPMENT .......................... 6

JRM INTERNATIONAL .................. 23

KIEFEL TECHNOLOGY................. 28

KYDEX .......................................... 36

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