Comparative study on cutting performance of conventional and ultrasonic-assisted bi-directional helical milling of CFRP

Compared with the conventional drilling, helical milling has obvious advantages in making holes of carbon fiber-reinforced plastic (CFRP). Nevertheless, rapid wear cutting edges readily causes some defects outlet holes, such as burrs and tearing. In order to improve hole-making quality CFRP, a comparative experimental study on ultrasonic-assisted bi-directional CFRP was carried out. The mechanism forward reverse analyzed two types machining, change laws forces hole wall were obtained by different machining means. results indicated that flank face dominated abrasive milling. With aggravation tool wear, no coating peeled off edge, edge remained relatively intact, form neither changed. Furthermore, milling, axial force diameter deviation restrained better than especially when occurred, fluctuation varied slowly. shear fracture predominated over bending fracture. Meanwhile, time variation effective rake angles improved chip breaking removing performance cutters, thus, enhanced obviously.