By Liz White, UT contributing editorDüsseldorf, Germany-At first glance, golf balls and automotive interior parts are not particularly similar products. But Krauss-Maffei Kunststofftechnik GmbH has recently used synergies between two of its three business units-reaction process machinery and injection moulding equipment-to develop novel processes, both involving polyurethane covers, for these two rather disparate types of product. For soft-touch automotive parts, Walter Tesche, head of Krauss Maffei’s reaction process machinery division, pointed out that there has been “a lot of interest” in the firm’s new dual process injection moulding/reaction process machine, since the group first previewed the development at a pre-K2004 meeting. The Munich, Germany-based firm thinks its process, using a shuttle-table mould, is a world first in the sector. This approach, christened SkinForm, allows a soft PU skin of varying thickness to be overmoulded on a hard plastic part-especially useful for automotive parts such as the injection moulded seatbelt buckle cover, flow-coated with PU, being produced on the Krauss-Maffei stand. “You can see it in action now,” Teschke told a large group of journalists at the K 2004 show, 21 Oct. The polyamide core of the article is injection-moulded on a Krauss-Maffei 160-750 CX and then flooded’ with a cast skin of polyurethane. The SkinForm process used a new variant of Krauss-Maffei’s modular Rimstar mixing/metering machine-the Rimstar Minidos. This is a highly automated and operator-friendly method of delivering very small shots-down to 3g/s Krauss-Maffei claims-“in a very stable process with the highest precision.”A second Minidos unit was being used on the Krauss-Maffei stand in a two-stage process to apply a PU outer layer to golfball cores. According to Tesche, this is “the first time a golf ball shell has been made of PU in a high-pressure process.” In the two working-stages a thermoplastic core is first inserted into a mould consisting of three sections, where it are encapsulated as two half-shells. Krauss-Maffei says a novel mould design enables the core to be retained precisely in the centre of the ball. Golf balls with optimum weight distribution, and “extraordinarily precise ballistic properties,” can be produced with this system, Krauss-Maffei claims. “
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