Surface grinding of CFRP composites using rotary ultrasonic machining: a comparison of workpiece machining orientations

Abstract

The carbon fiber reinforced plastic (CFRP) composites have superior properties of high modulus-to-weight ratio, high strength-to-weight ratio, good durability, high corrosion resistance, and low thermal expansion coefficient. These properties make them attractive in many different applications, such as aerospace, medical, transportation, and sporting goods. However, CFRP’s properties of anisotropy, inhomogeneity, and abrasive properties of carbon fibers in CFRP composites generate many problems, including high cutting forces, high torque, delamination, high tool wear, decomposition of matrix material, etc., in traditional grinding processes. Surface grinding of CFRP composites using rotary ultrasonic machining (RUM) is used to decrease these problems. However, there is no investigation on effects of workpiece machining orientations in such a process. This investigation, for the first time, studies effects of workpiece machining orientations and machining variables (including tool rotation speed, feedrate, and ultrasonic power) on output variables (including both cutting force in feeding direction and cutting force in axial direction, torque, and surface roughness). The results show that lower cutting forces and torque are generated by using 90° workpiece machining orientation and lower surface roughness is produced by using 0° workpiece machining orientation. The results are discussed and analyzed, and they will fill in the research gaps in RUM surface grinding of CFRP composites.