Formation mechanism of burr defect in aramid fiber composites based on fly-cutting test

摘要

Burr, tear, and other defects induced by machining make aramid fiber-reinforced plastic (AFRP) a representative difficult-to-cut material. For analyzing the formation mechanism of burr defect, a cutting mechanical model of AFRP was established to predict effects of the angle between the feed direction and the fiber orientation on tensile and shear behavior during the cutting process. The cutting process of AFRP was studied through the single-point fly-cutting method. The failure modes of AFRP was investigated by observing the morphologies of scratches, analyzing the cutting force and effect of tool tips. The results show that large burr defects are formatted by the tensile force during the cutting process, where the clear yield and necking phenomena of aramid fibers are observed. When the fibers are in the shear stress state, few burr defects can be found. Burr defect can be reduced by increasing cutting speed and sharpness of cutting tools. With the increasing of cutting depths, the elastic recovery phenomenon is significantly decreasing the machining quality.