It was not merely a matter of swapping out metal for plastic. In a traditional radio, the metal housing also acts as a Faraday cage, which ensures radio signals do not interfere with other vehicle electronics. The cage is needed for good reception, but more importantly, no one wants a favorite song to confuse the electronic throttle control. Metal cases are also complex structures, requiring 29 separate screws during assembly. Conductive plastics would still require screws to ground the electronics, he said. A new Faraday cage from a thin mesh screen that can be insert molded into a plastic case. The process has 29 patents pending. Insert molding added another wrinkle because the flexible mesh is harder to work with than rigid copper or other metals. Assembly time was reduced by more than 50 percent, and all the screws were replaced with a snap-fit system, going from 33 separate components to two. The 1.2-pound weight reduction achieved by swapping out metal for plastic saves fuel, and automakers can reduce the structural support needed within the instrument panel, which saves even more weight.
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