By: David Vink
EUROPEAN PLASTICS NEWS
January 8, 2014
DÜSSELDORF, GERMANY — The TecPart association for producers of technical parts in plastics, a member of the GKV association of German plastics processors, saw awards go to German companies producing parts for a range of end users, from consumer products to high-end cars.
Ten awards were named during the 2013 K Fair in Düsseldorf, compared with 13 at K 2010, 19 at K 2007 and 18 at K 2004.
The drinkclean-sportsbottle from Adoma GmbH of Wangen won for its two-component hard and soft closure in polypropylene and thermoplastic elastomer. The cap has a novel 90 degree tilting movement that enables the drinking nozzle to be used, then swung out of the way and protected without an additional protective cap.
BBP Kunststoffwerk Marbach Baier GmbH of Marbach won for a rollover bar cover for the 2011 model year Mercedes-Benz SLK car from Daimler AG. The part is backmolded to a preformed anodizable aluminum with a 20 percent glass fiber reinforced black Bayblend T88-4N grade of Makroblend polycarbonate/ABS from Bayer MaterialScience on an injection molding machine from Sumitomo Demag Plastics Machinery GmbH. Presswerkzeugbau Grossdubrau GmbH is the mold maker.
The TecPart jury praised the application of a sandwich structure which allowed the company to reduce the wall thickness, saving 60 percent of part weight over an equivalent part made by labor intensive gluing process. The aluminum preform takes up its final geometry inside the injection mold.
Fried Kunststofftechnik won for the 120-centimeter high polystyrene structural foam molded housing made for Fresenius Medical Care's dialysis equipment. Fried, based in Urbach, won an award for a similar part in 2010.
G.A. Röders GmbH & Co. KG received an award for a 5 euro pressure valve housing in 30 percent glass fiber reinforced nylon, which required very tight tolerances for the two throttles contained within the valve.
Röders, based in Soltau, says it was confronted with a challenge by the small mold cores used to heat the plastic material with each shot. In addition, a metal insert had to be pressed into one of the part's holes.
To hit the required high pull-out strength for the insert, the hole had to be over-compressed at the insert. This initially caused cracking at the knitline when the part cooled. Röders found the solution however by designing a 0.8-millimeter film overflow area in a slightly offset position relative to the knitline. Only once the mold has been completely filled does material flow into the overflow area, reorienting the glass fibers and effectively "wiping out" the knitline.
Kunststoff Helmbrechts, which is based in Helmbrechts, won two 2013 TecPart awards. One of these is a automotive roof control unit featuring use of a wide range of materials — PC, PC/ABS blend, PBT soft paint and nylon flocking, as well a variety of processes: single, two- and three-component injection molding, two-layer paining, laser marking, flocking, chroming and assembly.
With the three-component molding process, the company combines parts for the light guide, light diffusion and the surface design in a three-component index mold tool. Twenty single parts are finally used to assemble the complete unit.
The other award to the company was for the MyWave-3D demonstrator which the company uses to show its competence in design using a high gloss black panel with integrated capacitive switching electronic circuitry. The circuitry is in a wave-shaped injection molded interconnection device, made possible with the recent introduction of component insertion equipment that can automatically apply surface mounted devices on a contoured substrate.
Kunststoff Helmbrechts uses in-mold labeling with polycarbonate in-mold labels which are backmolded with polycarbonate, PC/ABS blend and liquid crystal polymer. The company has worked closely with another molder, MID-Tronic Wiesauplast on the circuitry.
An injection molded pressure tank in 30 percent glass fiber reinforced nylon brought an award to KTS Kunststoff Technik Schmölln of Schmölln for replacing conventional steel tanks. Although glass fiber reinforcement is essential to withstand the high pressure, it usually presents a challenge in this type of application because it does not form a well-sealed pressure-tight surface. KTS overcame the problem by using a high tool temperature in order to obtain a smooth surface, avoiding the void formation, sink marks and warping that are often associated with high tool temperatures.
The Warendorf, Germany molding department of household appliances producer Miele & Cie KG won a TecPart award for a washing machine door three years ago. This time the company won an award for the air channel component used in production of a clothes drier, including its sieve. Miele points out that the part is much more than a simple air channel: it also carries the axle for the drum supports, seals the drum aperture and door, accommodates the door and lock, in addition to its function of taking the moist air to the heat exchanger, which requires very close molding tolerances.
The lower part of the air channel consists of welded front and rear walls which are in turn welded to the upper part of the air channel. The round opening for the seal lip in the lower part is molded with a secondary injection unit mounted on the mold tool. During production of the upper part, a transparent viewing window is inserted and overmolded
Two awards went to parts made by ROS GmbH & Co. KG of Coburg, one in thermoplastic, the other in a thermoset. A vaned impeller wheel in 40 percent glass-fiber-reinforced polyphenylene sulfide with a central metal insert was praised for strict compliance with roundness as well as tight dimensions required for the part's height and exterior diameter.
The other wward to ROS involves a water pump bearing housing molded in phenol-formaldehyde reinforced with a combination of 35 percent glass fibers and 10 percent glass beads, as a part substituting cast aluminum, with a 35 percent weight savings. The PF material was chosen for its low abrasion and high chemical resistance. The part geometry was redesigned for the PF material to ensure it withstands the mechanical loads involved, to accommodate a silicone rubber seal instead of a metal one and for the molding process.