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Thermoforming wakes up to advanced technologies.

Thermoforming Wakes Up to Advanced Technologies

Thermoforming, especially of industrial parts, is shaking off its tradition of low-tech, low-budget production methods. Advances in "smart" heating control, plantwide process and production monitoring, sophisticated tooling, quick mold changing, and methods for in-line forming of previously difficult materials are starting to alter its "bargain-basement" image. Thermoforming processors by they have to innovate to gain new markets, or they may not be around in 10 years time.

But to change old habits thermoformers will have to invest capita. In an uncertain economy, many may rebuild and retrofit, not buy new for more efficient heating and process control. Thermoforming machinery builders also need financial stability to bring better technology to market. In past, their industry often acted more like it was the Wild West than the 20th Century, with lawsuits, colorful bankruptcies, financial shenanigans--even an occasional pistol drawn. (The president of one thermoforming machinery company allegedly pulled a gun on the president of another thermoforming machinery company over a debt. One president is in jail, both firms went bankrupt and both reappeared, though one has a new name.) Such well-known firm as CAM (Central Automated machinery Inc.) in Galdwin, Mich.; AAA Plastic Machinery in Fort Worth, Texas; Drypoll Inc. in Queens, N.Y.; and others have recently gone through bankruptcies, buyouts and restructuring.


High on the list of anticipated improvements is computer-integrated manufacturing, or CIM. To in-line formers, CIM means networking machine controls together with a central mainframe or personal computer, to allow remote monitoring and analysis for quality control, inventory control, production scheduling, accounting for scrap, price quoting, shipping, and downtime diagnostics.

"Thermoforming is going in the direction of the lights-out plant," says David IRwin, president of Irwin Research & Development Inc., in Yakima, Wash. "There's nobody I know of using CIM now, though some people are close. They're ordering our equipment now with process controls that can be tied in to a CIM system in a few years time." Irwin thinks a fully CIM-operated forming plant is two to three years away, even though "the tools are all here. It's just taking known technology from other industries and applying it to thermoforming."

Lyle Industries Inc., in Beaverton, Mich., may be the first supplier to offer a networking system compatible with CIM, tailored for thermoforming, but it's designed specifically to work with Lyle's own microprocessor controls. Lyle's CIM software, so new it hasn't been named or announced, was written inhouse by microprocessor specialist William Beltz, who also designed Lyle's microprocessor controls. Beltz says he wrote it "to minimize data traffic on this network. It's cost-effective to gather data directly from the thermoforming machine and give it to a central point for statistical analysis." An IBM-compatible personal computer is the central host for Lyle's software. The first system is about to be delivered to Milprint Inc., Fremont, Ohio.

The CIM program collects roughly 100 data points, plus alarm messages, operator changes and oven temperatures per machine every 3 sec. CIM management data can be accessed by users (for up to 15 machines) for statistical analysis or process control.


Several processors, both large and small, packaging and industrial, are already pioneering CIM for thermoforming. A thermoforming engineer at Inline Plastics Corp., in Milford, Conn., a maker of PS foam clamshells and other packaging, developed his own "home-brewed monitoring system," says manufacturing v.p. Frank Schepp. Watching the operating parameters of 30 thermoforming lines from his office, Schepp "can see, as orders come in, when they'll be filled and the price with real-time scrap costs."

Inline also uses a parts-quotation software module (MRP-II written for thermoforming by Data Technical Research in Jacksonville, Fla.) for many cost-accounting functions, but not linked to the plant's real-time remote monitoring. "That's a long-term project," he says. Schepp, not Inline, owns the software, which he hopes to license to a thermoforming machine manufacturer. "But CIM is a tough sell to thermoformers," he says. "It's the psychology of this niche to be cheap, though CIM has application across the board. If you don't control the process, you don't have repeatability. It's as important to a package former making parts in 0.1 sec as to an industrial former making a part every 2 min, who wants to meet auto company quality ratings."

Two other formers pursuing CIM are Placon Corp., a thin-gauge medical packaging former in Madison, Wis., and Mobil Chemical Co.'s Canandaigua, N.Y., foam tray plant. "We're one to two years away," says Placon process engineer Kurt Barlett. Both Placon and Mobil use Irwin machines. Mobil is developing a CIM-controlled R&D line to form a proprietary foam product.

Gates Formed Fiber and Auburn, Me., which compression forms auto trunk liners and other carpeted panels for boats and airplane interiors, between matched molds, has been close to full computer integration for two years. Gate's five continuous forming machines (modified Kiefel thermoformers "big enough to drive a truck into") are centrally monitored using Allen-Bradley microprocessor controls and software. Carpet making is also centrally monitored using a seperate system of Westinghouse controls and software. The two systems are "smarter than all of us that work here," says Greg Bluhm, one of Gate's two electronic technicians. Bluhm says the systems will soon be combined and will eventually hook up with Gate's central DEC Vax accounting and inventory system, which is online to customers who place orders electronically.

Another CIM contender, who asked to remain anonymous, is buying the first thermoforing CIM software written by PlantStar, div. of Syscon International Inc. in South Bend, Ind. PlantStar sales manager Ed Hansen says the program, based on PlantStar's Focus 100 real-time process and production monitoring system for injection molding, will customize a management reporting system, monitor six therformers (making refrigerator parts) and tie with Steelastic and Harrel process controls on sheet extruders. This real-time plantwide monitoring and reporting system will augment an MRP system, with which the company says it wasn't happy. Trial CIM will be running by the first quarter, and if successful, the whole system will be up by year end. The company president says it should pay for itself in efficiency in a year.

One processor's optimism notwithstanding, the big obstacle to CIM for most

thermoformers is "prohibitive cost to retrofit existing equipment," says Philip Scalvini, director of engineering for the Dixie Div. of James River Corp., Richmond, Va., which he says is "half as far along toward CIM as we'd like." Ovens generally have heaters wired in series and would need complete rewiring for the flexibility needed for CIM. On new equipment, oven zoning is improving, Scalvini notes.

ITW-High Performance Plastics in Glenview, Ill., four years ago bought $50,000 worth of integrated thermoforming controls, computers and remote monitors as part of a state-of-the-art plant assembled by Universal Dynamics Corp. of Woodbridge, Va. But CIM wasn't used because the company wouldn't spend another $20,000-25,000 to install it, for cabling, electrical hook-up and software development, says a former manager. "Ultimately, it became not a technical decision but a financial one--the plant ran fine without it, and it was hard to justify," he says. ITW-High Performance Plastics does elaborate q-c monitoring, but equipment operators physically walk around and check critical process parameters on a scheduled basis, says new operations manager John Schneider. Alarm conditions are set for each parameter so that corrective action can be taken long before product quality is affected, he notes.

CIM in thermoforming was also impeded because software for monitoring processes like blow or injection molding may not be compatible. PlantStar's Hansen says only minor adaptations of its software are needed for thermoforming. "Instead of measuring seconds per cycle as in injection molding, the thermoforming program watches ft/min or products/min."


New heat controls are in the works at several machinery manufacturers. "You'll see more optical infrared sensor heads in the future," replacing thermocouples, says Bill Kent, v.p. of marketing at Brown Machine. Infrared thermometers measuring sheet surface temperatures without contact have existed 20 years, but are only now getting "smarter," cheaper and easier to use, says Cliff Warren, president and co-owner of Raytek Inc., Santa Cruz, Calif., which introduced a new sensor with graphics display last March (see photo).

I-R sensors work like a camera, measuring emissions from a broad or narrow surface area of the sheet. Although these instruments are used to monitor heat-seal temperatures, only about 10% of thermoformers now use them, Warren says, but i-r sensors will be more widely used in the future to decrease startup time and improve quality. Software will also get more sophisticated, he says. For example, automatic controlling of indexing by sheet temperature measurement is an area where little software exists now.

Paul Kiefel GmbH in Germany also recently developed new thermoforming heat controls, called Harlequin, individually controlling 100-150 quartz elements using an infrared camera (see PT, June '89, p. 14; Sept. '89, p. 62). Harold Voigt, sales manager in Germany, says Harlequin was tested at Volvo in Sweden. Four more machines with the new controls are on order for Swedish and German customers, he says. Arie Koorneef, president of Kiefel Systems in Succasunna, N.J. says Harlequin "can adjust all elements separately, and the machine can control itself with the i-r camera." Harlequin also controls timing of air pressure, vacuum and other functions. In case of deviation, Harlequin notifies the operator; if more than one deviation occurs, the machine stops by itself. Harlequin uses Siemens microprocessor controls, but can use Allen-Bradley, Koorneef says.

Kiefel also developed a computer program for an auto company called Program System Infra-Red to calculate temperature adjustments for different draw depths in a complex part as part of the tooling design. "This shortens setup time for custom parts from several hours to only minutes," Koorneef says. The Infra-Red software, developed with the University of Cologne, Germany, is IBM-compatible and can work on any model Kiefel machine if it has individually controlled elements.

I-R sensors are part of a new touchscreen heat-control system from the reborn AAA Plastics Equipment Inc., now located in Seabrook, N.H. The first of the new systems was installed on a Brown machine at Ford Motor Co.'s Utica, Mich., plant. The touchscreen display outlines the part to be formed, indicating power level in the heating element both digitally and with a separate color for every 5% of heat intensity. Sheet temperatures can be similarly measured and displayed on the same or a separate CRT, measured by i-r sensors, for comparison and automatic correction of settings (see photo). Eight ovens at Ford will be converted, including switching from Calrod to quartz heating elements, which respond quicker.

Besides improving product quality, the heat controls and new heating elements reportedly cut energy use 40% by eliminating the preheat station. Heat energy can be cut 75% during short stops and 90% during warmup, says Lars Ekendahl, president and co-owner of the new AAA. Ekendahl says processors have less need for plug assists in forming complex parts, because of precise heat profiling.

AAA imports quartz heating elements under license from Pearlco. Ltd. in the U.K. and represents Anton Huber GmbH of Germany. V.P. and co-owner Richard Boswell says AAA has two patents and a software copyright pending on the controls. To protect its software (developed together with Virtech Inc., Nashua, N.H.), AAA will only use hardware from John Fluke Co. in Everett, Wash., which isn't readily copiable. AAA, which recently bought the assets of the old AAA and Drypoll, plans to change its name to Thermoforming Technologies Inc.

Comet-Kostur Co., Apopka, Fla., also retrofits with quartz heating elements (locally made in Florida) and zone control, says president Robert Kostur. The patent-pending system, which took five years to develop, "has a variable spectrum of infrared output, and uses split-second intervals of electrical input," for precise tuning, using two infrared sensors so a material absorbs the right heat and isn't overpowered, heating all the surrounding area. Progress Plastics, in Auburndale, Fla., has tested the heaters for two years, forming auto parts.

Edge-Sweets (PTI) Co., in Grand Rapids, Mich., a builder of urethane machinery (and until last year, of thermoformers for Comet-Kostur) is introducing for the first time its own line of thermoformers. John Wise (ex-president of the original AAA) is consulting on this machinery development. The new machines will offer optical pyrometers to measure surface temperature of the sheet, and Allen-Bradley or Square D microprocessor controls.

Cannon Shelley, formerly Shelley Thermoformers International Ltd., a U.K. supplier that last year became part of the Cannon Group of Italy, got a recent technology lift from Cannon, which designed a complete new controls package for Shelley. The computerized heat controls use small (5.25-in.-long) elements to concentrate heat for better control of ultimate part thickness. "This allows a former to use thinner plastic sheet in the first place, saving up to 0.5-1 mil, which can be the biggest saving," says Bruce Mazzoni, v.p. of sales and marketing at Cannon USA in Mars, Pa. He says Cannon-Shelley has installed complete thermoforming systems for auto instrument panels with the new Cannon controls, and expects new aerospace applications in Europe. Cannon USA is analyzing the U.S. market and is "more than likely" to build formers hre, Mazzoni says.

Adolf Illig Maschinenbau GmbH in Heilbronn, Germany, however, dislikes quartz heaters because of frequent breakage. Illig has a new ceramic heater almost ready to market, called FSR Flat Element, with "a baked-in mineral-wool-type insulator" to aim heat at the sheet, not the environment, says Bernd Lueder, Illig sales manager for the U.S. (Illig is represented by Plastic Systems, Inc., Atlanta.)



Brown Machine's engineeing v.p. Terry Brokoff says more companies will learn to extrude their own material. In-line forming, now only about 10% of the market, is energy efficient, using residual heat from extruded sheet, cooled enough to handle, then run into the former. "You eliminate cooling, rolling, storing, and transporting the sheet," he notes.

One company that recently began extruding its own PET sheet is Creative Forming, Inc. in Ripon, Wis. The company set up computer process controls for critical relationships among barrel temperature, screw speed, melt-pump speed, and other variables, and reduced thickness variation on 20-mil PETG sheet to 1.5% from 3% on previously outsourced sheet, says Creative president Robert Styer. Styer says new microprocessor controls and statistical methods let thermoformers get into extrusion without years of experience.

More in-line extrusion and forming without reheating may hep achieve greater depth-to-draw ratios (part diameter divided by part depth) by using the higher temperatures in the sheet core. Draw ratios are typically limited to about 1.5:1, but that will increase threefold in the next decade, says Frank Menichini, president and owner of CPI Custom Pack, Inc. in Malvern, Pa. CPI, using a CAD system, designed tooling with a 3:1 draw ratio for a new pregnancy kit to come on the market this month.

As an indication of what higher draw ratios can mean, Sencorp Systems Inc., Cedar Drove, N.J. (formerly Sentinel Machinery Div. of Packaging Industries) is demonstrating production of a thermoformed 32-oz PP deli tub, which marketing/sales v.p. Edward Husvar says, "Nobody else can do." Key features for this application on Sencorp's new model 3000 include closed-loop plug velocity readout on the CRT monitor, heavy-duty four-point toggle press to prevent material slippage through the clamp rings, and gradual splaying of the water-cooled chain rails to take up sheet sag.


Improving machine controls will also lead to more use of electric servo-driven platens in future, says Brown's Kent. Brown just introduced a new servo-driven CS-4500 continuousn former (see p. 17) to replace Brown's mechnical-drive. MC-4500 model at the same price. The servo-drive model is 30% moe expensive than pneumatic drives, but lower maintenance and geater process control should pay the difference very quickly, he says.

Servo-drives, which go through a gearbox direct to the toggle shaft, are more precise than hydrostatic drives, which connect through cams and linkarms. The servo also makes setup quicker because rotary position encoders on the output shaft correlate with allother functions. That means the servo can be set up automatically from stored electronic data for a job change--say, from a platen speed of 30 in./sec to 20 in./sec, while a pneumatic system takes 15 min or longer to adjust cylinder flow valves manually.



GE Plastics in Pittsfield, Mass., is helping to establish a small cadre of processors capable of complex twin-sheet forming (see PT, Aug.'89, p. 44-45). Charles Mulcahy, technical service supervisor for GE's twin-sheet development, trains customers to use GE's process. Cost of converting a standard single-station shuttle-type thermoformer is only about $3000, he says, for a heated inflation nozzle (made by Convectronics, formerly Merrimac, in Methuen, Mass.e, airflow control meter, and process controls to monitor aur temperature. Mulcahy says eight processors have converted and are now capable of making commercial airline heating and airconditioning ducts "much cheaper" than hand laid-up ducts.

So far GE's twin-sheet method is limited to 2 x 6 ft parts, and may encounter "obstacles to going much bigger," Mulcahy says. Twin-sheet forming with GE's Lexan polycarbonate or Ultem polytherimide also can't use sheet thinner than 0.040 in. And not every machine can process these materials. Brown has its own patented twin-sheet rotary forming machine on the market for years, but it's unable to process these GE engineering materials, Mulcahy says. Brown's rotary cycles slowly, so mating sheets of thin, high-temperature plastic, which cools rapidly, won't bond together. GE is also prototyping side skirts for buses in Xenoy PC/polyester alloy, replacing thermoset FRP, which is brittle at low temperatures.

Another proponent of twin-sheet forming is Snow Corp's EMC div. in Ft. Worth, Texas, which developed twin-sheet machines for a prototype after-market truck bumper (see PT Aug. '89, p. 44-45). The company is still trying to get a major automotive-related investment partner for this project, but has in the meantime built and sold some of the single-stage twin-sheet formers developed for bumpers. Snow/EMChs heavy-duty standard machines can also be programmed to do twin-sheet forming by chaning a dial.


Kiefel's Voigt says quicker mold change systems, including electronic recipes for job set-ups, will develop in the coming decade. Kiefel hopes to hasten mold-chaning by combining its pneumatic mold-locking with with an automatic sliding mold change it developed some 12 years ago, to come up with a machine that can change its own molds with a push of a button.

Edward D. Segen & Co. also offers a new quick-mold-change system (see p. 15), said to be done by one person in minutes, not hours. The system consists of QMC cylinders mounted in an adjustable, water-cooled mold base, with adjustable pressure box for quick changing of molds of different index lengths. Segen's patent-pendding QMC cylinders are sold separately for installation in thermoformers and trim presses.

One of several companies intending to try Segen's QMC system is Gage Industries Inc., Lke Oswego, Ore., which forms transportation-related parts and food packages like microwave tray lids. Even with microprocessor controls, Gage sales manager James Robert says a job change on a cut-sheet former can take 4-6 hr without QMC. James River's Scalvini says a complete change of an in-line machine can take up to two days.


Computer-aided design has already taken a third off led time in producing new packages, says Robert Kittredge, president of Fabri-Kal Corp., in Kalamazoo, Mich. "We get a sketch and create a computer design, which then goes into a 3D computer program to generate a tooling design in minutes, not hours," Kittredge says. "Or if the product design is already in the computer, we just transfer it to the tool design group. Our tool vendors are on-line with us, so they take our designs and cut tools automatically."

Another packaging former, Crystal Thermoplastics in Cumberland, R.I., recently bought a CAD system and an NC milling machine for part and tool design and tool cutting. These additions reduced tool-cutting time to 10 min from about an hour, says design manager Ray Collemer, even without a computer link between CAD and milling systems now being installed.


New-generation PP with improved melt-strength for melt-phase forming (aided by PP's price edge on PS) will make long-awaited inroads in package and industrial forming (see PT, Aug.'89, p. 51; Aug. '90, p. 43; Nov. '90, p. 14). And there's more to come: Philips 66 Co., Pasadena, Texas, is working on new PP/styrenic copolymer blends for thermoforming to reduce shrinkage and permit forming of wider webs. Phillips sees commercialization about two years off Dow Chemical Co., Midland, Mich., is reported to be working in this area as well.

Machinery adaptations to control PP sag, like an extra oven index and heated air under the sheet, will also be more widespread. Different mold materials, like bronze, with higher heat transfer efficiency than aluminum, may also help PP. Kiefel has new bronze mold tooling inEuropean trials now.


Dario Ramazzotti, v. p. sales and engineering at Edge-Sweets, expects strong growth for thermoforming in auto applications, especially composites and foams, Pjillips 66 Co.'s graphite-reinforced PPS thermopalstic prepreg, with a forming temperature of about 700 F, is being prototyped for auto underhood parts like a roker-arm and oil-pan cover, he says, requiring higher machine heat capability. Sencorp's Husvar also foresees in-line thermoforming of aerospace composites. A trend to heavier press tonnages in the future, he says, will lead to such heavy-duty industrial forming being performed on continuous, in-line machines rather than just rotaries or shuttles.

Computer integration is also coming to composite forming. Snow/EMC sold its first large thermoplastic composite forming machine with full integration, says president Bill Snow. The machine will form thermopalstic composite housings and other industrial parts up to 6 x 8 ft., with a CRT monitor on an umbilical cord some 20 ft from the machine with copyrighted software and controls.

Polyurethane foam is also a new possibility for thermoformers, says Edge-Sweets' Ramazzotti, who's doing developmental forming of urethane foam for '95 model cars. "We make a block of foam 4 ft high and cut 0.12-in. slices off it, which are thermoformed, with upholstery added in-mold, for sun visors and headliners." Auto door panels are now back-filled with foam, but formable foams wold be cheaper, he says.

BASF Polymers is prototyping thermoformed urethane foam auto headliners in Wyandotte, Mich., on a recently installed 60-ton forming machine from Astechnologies, Inc., Roswell, Ga. A "loose sandwich" of BASF's Elastoflex TF (thermoformable, open-celled rigid foam), adhesive and fiberglass is hot-mold-formed.

Traditional preheating doesn't work with fiberglass sheet, says John Stoll who heads the headliner R&D. United Technologies, Port Huron, Mich., may be first in the U.S. to use the approach commercially on '92 model cars, though some European cars have these headliners now.
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Author:Schut, Jan H.
Publication:Plastics Technology
Article Type:Cover Story
Date:Dec 1, 1990
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