Effect of drilling parameters on hole quality in drilling of pultruded GFRP composite material: Surface roughness, thrust force and delamination factor.

The use of fiber reinforced composite materials (FRP) has increased in many areas. These materials need to be processed with some machining methods according to their usage areas, but their machinability is difficult. In this study, surface roughness (SR), delamination factor (Fd) and thrust forces were investigated in the drilling of glass fiber reinforced composite material (GFRP) produced by pultrusion with a coated and uncoated drill. Microstructures of chips formed during drilling were investigated and their effects on surface roughness were determined. Three different cutting speeds (60, 70, 80 m/min) and feed rates (0.06, 0.09, 0.12 mm/min) were selected as machining parameters. At the end of the study, it was found that feed rate had a more significant effect on surface roughness, delamination factor and thrust force. It was observed that as the cutting speed increased, the surface roughness, thrust force and delamination factor decreased. The lowest thrust force and Fd occurred at a cutting speed of 80 m/min and a feed rate of 0.06 mm/min. However, the lowest SR was obtained at a cutting speed of 70 m/min and a feed rate of 0.06 mm/min.Better results were obtained with TiN coated drills compared to uncoated drills. [ABSTRACT FROM AUTHOR]