Abstract: The effect of a macro die casting defect (excess metal) occuring in the protruded hook of the framework for mobile telephone on mechanical properties was investigated by means of mechanical testing and scanning electron microscopy etc.It is indicated that the protruded hooks,with heavy excess metal,small excess metal and no excess metal,all underwent more than 20 N push force,and met the needs of the assembling process.The porosity formed during die casting process was very likely the main controlling factor for the mechanical properties of the product,nor the excess metal.