An investigation of the effect of tool approaching angle in turning of CFRP composite materials

Abstract Carbon Fibers Reinforced Plastics (CFRP) composite material bars were machined on the lathe. In experiments −15°, 0°, 15°, 30°, and 45° approach angles, 0.1 mm × rev -1 , 0.15 mm × rev -1 , and 0.2 mm × rev -1 feed rates and 560 rpm, 800 rpm, and 1120 rpm spindle speeds were selected. At −15° and 0° approach angles, the deformation influence was dominant on surface roughness and chip morphology, while the cutting effect taking place at the cutting edge was dominant at 30° and 45° approach angles. Primarily at 45°, the most significant roughness values and the shortest cut fibers were achieved due to the occurrence of maximum shear stress according to Tresca. However, fibers were removed from samples on the whole form as bundles, without any cutting, at −15° and 0° approach angles, by the effect of deformation. According to ANOVA, regression and variance analysis results were obtained with p-values and probability results of surface roughness smaller than 0.05 and 5 %, respectively. These results showed that the feed rate was the most influential parameter for turning of CFRP material, followed by the approach angle and spindle speed, respectively. However, the least influential parameter in the processes was spindle speed.