Mirror, mirror… For injection molding [Jan 2012]

At Magna Spiegelsysteme GmbH, everything revolves around mirrors. Located in the tranquil village of Assamstadt in the north of Baden-Württemberg, Germany, the company produces interior and exterior mirrors for the premium manufacturers of the German automotive industry. If you drive a Mercedes, BMW, Audi – or a Porsche – then you will have glanced countless times into an exterior mirror that was made at Magna in Assamstadt. An impressive total of 14 million plastic parts leave the plant every year. The complex removal process for the high-quality plastic mirror housings is entrusted to KUKA robots
Magna Spiegelsysteme in Assamstadt belongs to Magna Mirror Systems, a subsidiary of the leading global automotive supplier Magna International Inc. The range of products developed and manufactured by Magna Mirror Systems includes interior and exterior mirror systems, electrochromic glass, actuators, camera vision systems and door handle systems. “Magna Mirror Systems is a global supplier to the automotive industry and one of the largest producers of car mirror systems worldwide,” explains Ralf-Peter Hericke, Head of Injection Molding at Magna Spiegelsysteme in Assamstadt. Since 2007, Magna in Assamstadt has relied on the competence and flexibility of KUKA robots for demolding and packaging operations: shelf-mounted robots of type KR 60-4KS and variants from the KUKA product range, which are ideally adapted to the complex removal process with their optimized reach, weight and acceleration.
Degrees of freedom – the top argument for the jointed-arm robotRemoval, weighing, cutting and packaging – this is the complicated constellation of tasks to be handled after the injection molding of a mirror housing at Magna. The decision-makers in injection molding had the idea of using jointed-arm robots for the complex removal operation. Previously, the parts were demolded in twos or fours using a linear robot and set down on a conveyor system. The automation solution from the Augsburg-based technology leader gives Magna more degrees of freedom than conventional handling equipment. “That is a big advantage, especially when switching products,” says Ralf-Peter Hericke.
“The online monitoring, the 100% weighing check, and the possibility of implementing any reworking of the parts within the creation process itself – all this is accomplished by the KUKA robots”, says Gerhard Leutwein, process engineer in Injection Molding.
Elegant solution for complex processesFor the production of a mirror housing at Magna, plastic granulate is first melted in the screw chamber of the injection molding machines and injected into a closed mold. The product must then cool in the mold. The ejectors move the part into the removal position, at which point the KUKA “Speed” robot KR 60-4KS comes into play: equipped with a removal gripper from KUKA system partner SAR, the robot demolds the product, moves it out of the machine area, cuts off the various sprues and sets the mirror housings down in pairs on the scales. After the weight check, defective parts are separated out straight away, just as in the tale of Cinderella: “the good into the pot, the bad into the crop”. If the product passes the quality check, it is immediately packed in a box by the KUKA robot. Where necessary, the KR 60-4KS also inserts a slipsheet to protect the high-quality mirror housings during transportation.
“With a linear robot, it would not have been possible to implement the entire process,” says Ralf-Peter Hericke.
Space-saving concept, short cycle timesThe limited space available was a major consideration for Magna: “We save a huge amount of space because we can install the KUKA robots as shelf-mounted robots on the non-operator side of machine,” explains Gerhard Leutwein. This compact mounting arrangement allows the injection molding machines to be installed very close together; the space requirements for the peripheral equipment on the non-operator side of machine have also been optimised. These applications could only be implemented with the lightweight robots from Augsburg – other automation solutions would have been much too heavy. Magna currently has 15 KUKA robots in operation, and this number is set to grow further. To ensure correct handling of the KUKA robots, Magna had its personnel trained by KUKA’s system partner SAR.
Injection molding plants like Magna Spiegelsysteme today face tough global competition. To meet this need, KUKA Roboter GmbH supplies flexible automation solutions which provide a high degree of cost-effectiveness through minimised removal times.
The Speed robots from KUKA achieve cumulative accelerations of up to 10m/s²: the short cycle times help to increase Magna’s competitiveness. Ralf-Peter Hericke is convinced, “Our success has proved us right. Opting for KUKA robots was the right decision.”

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