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Ultra-thin, decorated composite components in a single processing step

News International-French

4 Jul 2016

Leonhard Kurz Stiftung & Co and Bond-Laminates have thus developed a material combination and the associated mold technology to produce decorated housing parts with thin walls for these devices in a single processing step.

One convenient feature of IT devices, such as smartphones, tablets and notebooks, is that they are very lightweight and compact, but still durable. “We start with a semi-finished thermoplastic composite with the trade name Tepex dynalite. This is formed by closing an injection mold, back-injected, and decorated inline using an In-Mold Decoration integration process specially developed for this purpose, an advancement over Kurz's existing in-mold process. It involves the use of a transfer coating system,” explains Andy Dentel, project manager at Bond-Laminates.

Engel Austria GmbH in Schwertberg engineered a highly automated manufacturing cell for the new material combination that is suited to large-scale production. The new manufacturing process from Kurz and Bond-Laminates will be demonstrated live for the first time at Engel's stand at K 2016 in Düsseldorf. The demo product is a housing component with a wall thickness of just 0.6 millimeters, which both companies will have on display.

High strength and stiffness
The Tepex dynalite material is reinforced with continuous glass and carbon fibers, embedded free of air inclusions in a polycarbonate matrix. “The advantage of our composite material is its very high strength and stiffness, combined with good toughness. These properties are what enable us to reduce the wall thickness so much, without compromising on the mechanical performance of the decorated components,” says Dentel. Because the component is coated directly in the injection molding process, using a dry coating technology developed by Kurz, an additional coating process step can be eliminated. The result is substantial savings on costs, logistics, energy consumption and resources. “You don't have to invest in a coating line, and you don't have to separately store, transport, clean or pre-treat the injection-molded parts prior to coating. In other words, all the many processing steps required to coat composite components can be eliminated, since they are now integrated into the In-Mold Decoration process. In addition, you don't have any coating waste due to overspray,” Dentel continues.

Function integration cuts costs
Integrating functions via the injection molding process reduces costs even further. For example, the demo part has an integrally molded frame around the edges made of a flame-retardant polycarbonate reinforced with 50 percent short glass fibers. Snap connections and screw bosses are also integrated into the part.

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