Experimental analysis of drilling forces and edge defects in SiCp/Al composites using PCD drills

Abstract SiCp/Al composites are increasingly utilized in electronics, automobiles and other fields, where their drilling process significantly impacts their application and reliable performance. This study presented an experimental investigation into the thrust drilling forces and edge defects encountered when drilling SiCp/Al composites with PCD drills. The experimental findings demonstrated that the drilling velocity has a minimal impact on the thrust drilling forces, whereas the thrust drilling forces increase with higher feed rates. The edge defects are closely linked to variations in thrust drilling force. The entry edge defects are primarily caused by crack growth under compressive stress, including small macro fracture notches, SiC particles shedding and brittle fracture along with plastic bulge. The exit edge defects are mainly created by the debonding of SiC particles and matrix under tensile stress. Macroscopically, exit edge defects are annular along the edge of the hole. Microscopically, they include the fracture, shedding of SiC particles and the ductile fracture of the matrix.The effect of drilling velocity on the entry and exit edge defects is not significant, but both types of defects increase significantly with higher feed rate.