This is die casting for commercial converter housing supplied for Huawei and is made of ADC12# with sand blasting and CNC surface treatments. Converter housing gives high filling requirements because there will be coarse teeth caused by large sand inclusions when the molds aren’t be filled with molten metal completely. In molds designing process, we changed design plans for about 10 times according to designing parameters and simulations before getting the ideal structure. The actual mass production proved the designed mold was good enough to achieve 91% yield.