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November 4, 2003

8 Min Read
Thermoforming advances focus on machine innovations, tooling

From top: A thermoforming/rapid prototyping machine from Geiss is equipped with a CNC router, a Sinumerik 840D control, and cutter length measuring inside the machine. The speedboat above was formed by Better Bath Components on a Geiss machine and won the People?s Choice Award, Cut-sheet Div., at the SPE Thermoforming conference in Cincinnati. Left, these bi-fold clamshell packages from Alloyd Co. won the Consumer Packaging Award at the conference. Far left, the canopy around this Geiss thermoforming machine reduces noise and prevents dust from escaping.

Thermoforming continues along a path to becoming a cutting-edge, widely accepted process, thanks to advances in processing machinery and materials creating new avenues for applications.

Equipment and materials are playing a big part in expanding the [thermoforming] industry,? commented a Davis-Standard spokesperson recently at the SPE Thermoforming Conference held in Cincinnati, Sept. 13-16.

Thermoforming?s anticipated growth is prompting some expansion among processors. Rexam Containers? director of operations Steve Tyre commented that Rexam, for example, has expansion plans in the works. Rexam (Union, MO) makes barrier food packaging for shelf-stable applications. A new coextrusion line was added in May 2003, and the company is looking at adding more coex capacity as demand for formed barrier food packaging increases, replacing paper or glass in many applications.

Geiss AG, German manufacturer of thermoforming and trimming machines, recently opened an office in Elk Grove, IL under the name Geiss Thermoforming USA LLC and introduced a new vacuum forming system to the U.S. market. The new machine, according to Geiss president Manfred Geiss, is a single-station vacuum former that supports the sheet and allows prestretching after heating. ?Typically, American machines are rotary, multistation machines with an open chamber, which doesn?t support the sheet during the process,? noted Geiss. Not one to be bashful, Geiss says, ?Our machine provides better processibility, better quality, better distribution, and more flexibility.?

The support that the Geiss machine provides for the sheet reduces sag during heating; it blows a slight bubble after heating, yielding improved uniformity and repeatability. Also, the company introduced a new halogen heating system that allows heat to penetrate the sheet and reduces heating time. Geiss also introduced new clamp systems, top and bottom, that are infinitely adjustable without additional components required. ?Changeover is automated for the whole system, top and bottom, during the mold change,? Geiss explains.

Geiss also offers the Parametric design system in which the processor chooses the machine size required and the computer system designs the machine in about 10 minutes. For example, the machine that thermoformed a large boat (see photo above) was designed using the Parametric system. Additionally, Geiss can design and supply both the CNC router and the vacuum forming machine to provide thermoforming and trimming in one unit. ?Our challenge is to make the most advanced and highest productivity machines globally,? Geiss added. Geiss exports 70% of its products and has facilities in Australia, China, South America, and now North America.

The Single Station Pressure Former from Maac Machinery Corp. has a variable speed motor-driven platen and lift table drives, and a TEC 480-oven control system that saves oven component space by 50% and is said to reduce maintenance.

Better temperature control has always been the demand of processors of thermoformed parts. To that end, American Catalytic (Branford, CT) offers multizone heaters in a single unit, making installation easy and the equipment more cost effective. John Critchley says the trend in the thermoforming industry has been toward more zoning to provide better heat control. American?s Multi-Zone catalytic heater comes with the company?s Electronic Pressure Management System, to provide precision zoning and control for catalytic heating in thermoforming.

Michael Alongi, sales manager for MAAC Thermoforming Machinery (Carol Stream, IL), says that turnkey systems are becoming more in demand from processors. ?They?re more cost-efficient, and offer the fastest way to get new products to market,? he says. ?Let the machinery manufacturer do the engineering to meet the specifications of a requirement, and there?s less confusion because the design and build is all under the direction of one supplier.? The company is also increasing the size of its frames to accommodate large parts, and it developed a quick mold change unit with adjustable clamp frame to take a 2- to 4-hr mold change to 20 minutes. Also, MAAC is upgrading its software to memorize the mold system setup to reduce setup time.

Zed Industries? Michael Henman notes that inline systems that allow formers to do it all from sheet extrusion through the forming operation is what processors want. Zed (Vandalia, OH) manufactures inline and heavy gauge pressure formers, and features innovative mechanics that eliminate toggles for increased pressure forming. Materials up to .12 inch can be formed with 120-inch indexes and 40-inch depth of draw.CMS Villa Plastic is an Italian-based maker of thermoforming machinery and auxiliary equipment, headquartered in Zogno, Italy. The company now has a sales and service facility, CMS North America Inc., in Caledonia, MI. CMS has a new machine that will be introduced soon, but was not ready for the conference.

Although thermoforming technology is improving part quality out-of-the-mold, secondary operations are often still necessary. Quintax CNC Routers, a division of Ferry Industries Inc. (Stow, OH), featured a complete line of 3- and 5-axis CNC routers for plastics to make quick work of secondary routing operations. Quintax?s routers feature ease of programming and a variety of functions that accommodate complex machining operations.

To improve sheet temperature control, Raytek Corp. (Santa Cruz, CA) has new software for its TF100 Process Imaging System for thermoforming. It corrects for the distortion of the thermal images caused by nonlinear sheet movement on rotary and inline machines and allows thermoformers to monitor and record temperature distributions of virtually any heated plastic part. With this information, they can improve product quality and uniformity, thus reducing scrap, and improve operating economy by quickly detecting defects and failed heating elements.

A no-spill gas can from Shepard Thermoforming received the Housewares Award, Roll-fed Div., at the SPE Thermoforming Conference.

The Recreational Products Award in the Cut Sheet Div. went to the Pelican-camouflaged fishing boat, said to be ?Perfect for sneaking up on all those little critters you?re trying to kill.?

Tooling Contributions

Chris Dolny, thermoform tooling manager for Producto (Bridgeport, CT), a Precision Manufacturing Technologies company, said that another contribution to the growth of thermoforming is the tooling. ?We are doing sidewall venting and other techniques to improve the quality of the parts,? he says. The company produces tooling for food containers, berry baskets, and foam containers. ?We?re seeing a lot of applications in foam containers; we?ve done a lot of these recently. Fruit packaging is big.?

Rapid tooling for thermoforming is also advancing. Nest Technologies Inc. (Studio City, CA) offers its Vacplate 1155 microporous tooling plate for thermoforming applications. It gives users intricate detail and resolution, transparent forming, improved thickness uniformity, and fast forming cycles. It also reportedly provides excellent machinability, surface quality, strength, and durability at a low cost.

Larry Mears, executive vice president of Freeman (Fremont, OH), a maker of thermoform tooling, cutting dies, cutting parts, and press cutting equipment, said he?s seeing more demand for polypropylene tooling for large-bed, high-speed, high-volume food packaging applications. ?Polypropylene is cheaper, the clarity has gotten much better, and the strength in the thinner gauges competes easily with PET,? he notes. He also agrees that thermoform tooling is generally improving to provide ?faster cycles and better part quality out of the mold.?

Jack Stritch, business development manager for Freetech Plastics Inc. (Fremont, CA), says the company made an investment this year to add twin-sheet thermoforming to its capabilities. ?The biggest chunk of the investment is the tool,? he says. ?We bought a pressure-forming machine from Modern Machinery Inc. [Beaverton, MI] specifically to get into twin-sheet forming.?

Freetech also bought an additional twin-sheet clamp frame, to allow the company to perform different types of twin-sheet work, depending on the application. ?We built the flexibility into the equipment,? Stritch explains. ?It was a custom-designed machine for us, but we built the flexibility in so we can meet a wider range of customers? needs. So far, it?s been a good investment and has opened up one, and possibly two, new markets for us already.?

Twin-sheet forming is becoming an alternative for and competes with blowmolding in a variety of applications. Stritch notes that Freetech is doing some twin-sheet forming using ?fairly exotic? materials such as Delrin. ?We were the first company to pressure-form Delrin,? Stritch states.

This InVision printer housing is a prime example of a pressure-formed application incorporating complex tooling containing slides and lifters, to form the complex shape and provide excellent aesthetics.

These McDonald?s cups from Creative Forming received the Food Container Award, Roll-fed Div., at the SPE Thermoforming Conference.

Machinery makers and moldmakers are responding quickly to thermoformers? needs, and the general consensus by most in the thermoforming business is that machinery and tooling is helping the process become faster, more consistent, and more precise.

Stritch adds that increasing demands for complex parts in engineered materials means that first and foremost, the tooling has to be exact with respect to temperatures. When Modern built Freetech?s twin-sheet former, Stritch says there were specific requirements for keeping mold and material temperatures as exact as possible. ?Temperature-controlled molds are critical for making good parts, particularly for molding polycarbonate,? he says. ?When you use infrared [heating], which we do, there?s a lot of guesswork. You have to be careful of mold temperature, sheet temperature, duration to get the sheet from the oven to the tool, and cooling time. A lot of the technology evolves around the temperature.?

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