Unusual Insert Molding Yields Integral EMI/RFI Shielding

One of the winners of the recent SPE Automotive Innovation Awards embodies a number of technical advances in manufacturing worthy of 29 U.S. patent applications. It involves a delicate job of insert molding a preformed metal mesh to produce a car radio case with built-in EMI/RFI shielding. It’s a development that could have broad application in automotive electronics, according to the developer, molder, and assembler of the Delphi Ultra Light Radio, Delphi Electronics & Safety Div., Kokomo, Ind. The wire mesh “Faraday cage” was overmolded with PC/ABS with 16% glass. The resin was 100% reprocessed post-consumer and post-industrial waste. Two plastic parts with snap-fit and slide-lock assembly replaced a sheet-metal case with 29 screws (33 components total). The result was a 22% weight saving (1.2 lb), faster assembly, improved shielding performance, improved internal cooling, and improved employee safety (no danger of metal cuts). Proprietary technology developments included cutting and forming the wire mesh and robotic transfer of the mesh without deformation to the injection mold, where special magnetic tooling holds it in the proper location.