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Die Hard Innovation

It keeps going and going and going — extrusion die innovation that is. “The techniques we're using today are far more advanced than even ten years ago,” states John Ulcej, executive VP of technology, Extrusion Dies Inc. (EDI), Chippewa Falls, WI. “We're improving our analytical techniques. If you look at EDI's annual R&D budget, you'd see a significant portion spent on software development. For our manufacturing and design, we're relying on the CAD/CAM process more and more heavily. In the past, you wouldn't even be able to come close to machining extrusion die geometry achieved now,” he adds.

With today's advanced computer technology, extrusion dies, both blown and cast, can be designed to deliver seven-layer film (even more layers definitely are possible). And despite the many layers, this is film that's getting flatter and more uniform in terms of polymer distribution.

It's the flow design technology has helped to improve, say the experts, which they describe as “flow channel” and/or “manifold.” Explains Gary Oliver, senior corporate scientist, Cloeren Inc., Orange, TX, “For optimum fluid flow, especially in coextrusion, manifold cross-section is critical. [In the past decade], the most significant changes have been in manifold design.”

Besides optimum flow, adds Oliver, “converters are demanding more flexibility in their extrusion dies.”

Norbert Plewa, diploma engineer — extrusion dies general manager, Reifenhäuser, Troisdorf, Germany, reports he's experienced similar demands. “They want them to run as long as possible…and they want the changing, dismantling, and cleaning of the die to be as quick as possible. Die design is modified [to accommodate these needs]. To make the die easier to maintain, for instance, the number of bolts is reduced, the bolt size is reduced. We sell more and more dies with removable lower lips; if a customer doesn't need to adjust the gap, he uses the removable lower lip to clean the die's front area.”

According to the experts, as good as die design is today, the future looks even better. “Future developments…will include…the synergy of various aspects of die design,” Oliver explains. “Integrating mechanical design with precise rheological modeling and thermodynamic properties of the system will [expand the next generation's…design]. Better data input into a model, and better models, [will be] key to future development in extrusion die technology.”

And the future's “better models” will continue to add die versatility. Plewa explains: “I think modifications will make dies even more flexible. For instance, in coextrusion dies…the customer wants the ability to extrude different materials — there are few single-purpose lines.” He says even customers not processing a variety of materials today often look to the future when buying a system. “[They may say], ‘Okay, we don't know…what we'll be running in two years, but is your system capable?’ Thus, we are producing more built-in flexibilities.”

The future in extrusion die technology also looks to expand relationships between die manufacturers and resin suppliers even further. “We have tooling in [various] resin manufacturers' labs,” says Ulcej, “which means they can do development work there. Also, we work with them at our customers' sites.”

Film converters would be wise to watch extrusion die innovations now and in the future. Whether you're running three-layer applications or are into the seven-layer-plus products, extrusion die development may be what's going to take your bottom line just where you want it to go.


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