Precision Electrodischarge Machining (EDM) of Aluminum Matrix Composites

This paper contains description of composites with Al-20Si-3Cu-1Mg matrix and particle reinforcing phase Al₂O₃ of 2.5-10% volume fraction. During EDM, holes of 0.5 mm diameter were drilled in plates cut from composite bars. Average drilling speed Vd, accuracy of the holes drilling and surface roughness Ra were determined. It was found, that the energy of a single discharge is the basic parameter influencing the EDM process. The higher the energy of a single discharge, the higher the productivity and the higher the surface roughness of the holes. The effect of material and volume fraction of the reinforcing phase in composite on the drilling speed was also noted. When the volume fraction of this phase increases, the drilling speed is reduced.