Experimental and analytical investigation of the drilling forces of the carbon fiber reinforced plastics including thermal effects

Abstract

We present the experimental and analytical investigation of the drilling forces for unidirectional carbon fiber reinforced plastics (CFRP) composites according to different machining parameters. In the analytical thrust force model, the chisel edge region is classified as an extrusion operation and the lip is considered as a orthogonal small-element cutting region. The chipping, pressing, and bouncing regions of the lip are incorporated into this thrust force model. In addition, the analytical model includes the thermophysical properties of CFRP by incorporating softening of the material due to drilling processes. Based on the developed model, the thrust force curve for all drilling stages is analyzed in time-domain considering both cutting conditions and material properties. Comparison between predictions and experiments was performed on three CFRP samples with different fiber volume fractions and sixteen cutting conditions. It was observed that the predicted forces can capture the trend of the experimental data with the relative small error. Time-domain analysis and fluctuation evaluation were also used to better understand the mechanism of thrust force during CFRP drilling.