LEONHARD KURZ Stiftung and Bond-Laminates have developed a new material combination and the associated mould technology to produce decorated housing parts with extremely thin walls for IT devices, such as smartphones, tablets and notebooks in a single processing step.
One convenient feature of these devices 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 mould, back-injected, and decorated inline using an In-Mold Decoration integration process specially developed for this purpose, an advancement over KURZ’s existing in-mould process. It involves the use of a transfer coating system,” explains Andy Dentel, Project Manager at Bond-Laminates.
According to Bond-Laminates, ENGEL AUSTRIA in Schwertberg, Austria, engineered a highly automated manufacturing cell for the new material combination that is suited to large-scale production.
The Tepex dynalite material is reinforced with continuous glass and carbon fibres, 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 moulding 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-moulded 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.
Bond-Laminates explains that integrating functions via the injection moulding process reduces costs even further. For example, the demo part has an integrally moulded frame around the edges made of a flame-retardant polycarbonate reinforced with 50 percent short glass fibres. Snap connections and screw bosses are also integrated into the part.