Improvement of geometry of multi-tooth milling cutter for surface damage suppression in milling of CFRP with theoretical method

Abstract

Multi-tooth milling cutters with segmented right- and left-hand helical cutting edges have been developed to minimize surface damages in milling carbon fiber reinforced polymer (CFRP). However, current studies on the cutting performance of the cutter under various tool geometries are mainly conducted through experimental methods, and the removal mechanism of the surface fibers during milling has rarely been revealed. Therefore, an effective method to improve the geometry of the cutter is required to be proposed to suppress surface damage. In this paper, theoretical models considering multiple cutting actions of the cutter are established to calculate the deformation and fracture of surface fibers at various cutting conditions during CFRP milling. It is found that the fiber would be effectively removed with large cutting depths and axial forces directed to the inside of workpiece. Then, the cutting depths of the right- and left-hand helical cutting edges during milling are quantitatively compared, identifying the segmented left-hand helical cutting edge (SLHCE) to be more important in affecting surface damage. Subsequently, a novel arrangement of segmented cutting edges is proposed by designing overlapping part between adjacent SLHCEs in the circumferential direction, which increases the cutting depth of SLHCEs and helps to inhibit burrs. Finally, the effectiveness of the proposed milling cutter in damage suppression is validated with experiments. This research could provide theoretical bases and technology guidance for low-damage milling of CFRP.