Machinability of Kevlar (R) 49 composite laminates while using standard TiN coated HSS drills

This article addresses the machinability of plain weave Kevlar(R) 49 prepeg composite laminates of different thickness while using 135degrees split-point TiN coated 6mm diameter HSS drills. The effect of composite preparation parameters and the drilling conditions on the machinability of the laminates is assessed using the drilling thrust force, cutting torque, and specific cutting energy. The thickness and processing time of the laminates as well as the drilling process parameters were found to influence the maximum value of thrust force and torque as well as the quality of drilled holes. The wear features of the drills used in machining Kevlar composites have been found to be different from the conventional wear patterns that occur during drilling metals and alloys.