The Turkish plastics processing company Pürplast has seen great success using an LFI system from KraussMaffei for series production of light fiber-reinforced components. "The critical advantage of the LFI procedure is that the endless glass fibers are not cut into filaments until right before processing," explains Erich Fries, Head of the Business Unit Composites & Surfaces at KraussMaffei. "Therefore there is no need to insert a preformed glass mat into the mold," continues Fries. These are the reasons that prompted Pürplast to decide to invest in an LFI system from KraussMaffei. "The LFI system from KraussMaffei with its process-technology advantages fits in exceedingly well with our strategy," says Mehmet Sismanoglu, Managing Director and owner of Pürplast. One of the Turkish company's uses for procedure is increasing quality when producing large-surface visible parts for commercial vehicles—including overhead compartment cover panels for coaches—and to reduce the manufacturing costs.
The LFI process unit consists of a cutter and a mixing head. The cutter draws in the roving, chops it into fibers of the preset length and shoots the fibers into the mixing head. The mixing head mixes the reaction components and discharges the PU resin into the mold simultaneously with the fibers.
In this way, the chopped fibers are uniformly wetted and their distribution in the mold is isotropic. Consequently, the manufactured components demonstrate high strength values and low thermal expansion. Both the length and amount of fibers in the mixture can be varied during processing to produce zones capable of withstanding higher loads thanks to higher fiber concentrations and increased fiber lengths.
In order to give LFI components a high-quality exposed face, a thermoformed film can be placed into the lower mold half. Then the mixture of PUR and glass fibers is applied to this film and pressed. "Due to the excellent visual properties of the component surface, there is no need for any subsequent finish. Another variant of the procedure uses what are called honeycomb structures in combination with the LFI technique. This produces components with very low weight and yet at the same time high rigidity," adds Fries.
Pürplast employs about 290 employees in the Turkish city of Kocaeli approximately 100 km east of Istanbul. The company still have 42.000 m2 production area in 4 buildings Founded in 1981, the company specializes in manufacturing PUR components for the commercial vehicle industry. The product line includes instrument panels, seat pads, exterior body parts, armrest, partition walls, handles and steering wheels. The annual turnover is currently approximately 25 million euros. Pürplast ships more than half of the production value to Turkish companies Mercedes Benz, MAN, Temsa, Otokar; the company exports about 40 percent of the production to 38 different countries in all around the world. Main customers are Daimler AG, Evobus, MAN, BMW AG, VDL, VANHOOL and VOLVO.
The corporate philosophy at Pürplast has as its objective to use innovative production engineering to produce cost-effective products that satisfy the high quality requirements. In addition to the LFI processing, production at Pürplast also makes use of classic high-pressure PUR processing, thermoforming and metalworking. The company also operates its own moldmaking shop.