October 2008

In automotive design, there is an increasing trend towards large-sized, three-dimensional glazing components such as roof modules and panoramic roofs.

Polycarbonate is the ideal material for producing these transparent components, above all because it offers much greater design freedom than glass but also because it has enormous weight-reducing potential. The most commonly used process for manufacturing such parts is that of injection compression molding. Bayer MaterialScience AG, which, with its BayVision® brand, is one of the leading suppliers of materials, process and design know-how for polycarbonate automotive glazing, has now succeeded in significantly improving the predictability and calculability of the injection compression molding process for large transparent 3D glazing components. "Simulation of the injection compression molding and injection molding processes for smooth, two-dimensional glazing parts has been state of the art for many years, but we have taken it a step further,” explains Olaf Zöllner, head of the Injection Molding team in the Polycarbonates Business Unit. “We are now in a position to accurately simulate the injection compression molding process for parts with a 3D geometry."

The challenge when working with the injection compression molding process on large and complex glazing parts is to control the process parameters to ensure low-stress parts with excellent, easy-to-coat surfaces. The simulation modules from Bayer MaterialScience make it possible to calculate, for example, how the wall thicknesses and melt velocities change on closing the injection compression molding tool, where melt stagnation occurs, and how the melt stresses perpendicular to the opening direction of the mold are distributed. "Our simulation models depict the processes in the mold during the filling and compression phases completely realistically. This has been confirmed by comparative trials in our technical service laboratory with elaborate 3D components on an injection compression molding line with the relevant molds," says Zöllner.

Customers can use the new simulation tool to help them with their projects. "We regard this as a particularly valuable service element of BayVision® in view of the trend towards large 3D glazing modules made of polycarbonate, because it can help to get these complex parts onto the production line more quickly," says Volkhard Krause, head of the Automotive Glazing team at Bayer MaterialScience.

About Bayer MaterialScience:
With 2007 sales of EUR 10.4 billion, Bayer MaterialScience is among the world’s largest polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, electrical and electronics, construction, and sports and leisure industries. At the end of 2007, Bayer MaterialScience had 30 production sites and employed approximately 15,400 people around the globe. Bayer MaterialScience is a Bayer Group company.

Find more information at www.bayermaterialscience.com.

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