EXPERIMENTAL INVESTIGATION OF VIBRATION ASSISTED HELICAL MILLING OF 7075 ALUMINUM ALLOY

摘要

Vibration-assisted helical milling (VAHM) is a novel machining process in which an axial ultrasonic vibration is superimposed to the milling cutter. The current work aims to experimentally investigate the influence of applying ultrasonic vibration on the machining performance during helical milling of 7075 aluminum alloy. A full factorial design of experiment is first implemented. Analysis of Variance (ANOVA) is then performed to study the effect of rotational speed (n), tangential feed (F_t), helical pitch (P) and ultrasonic vibration on the process performance. The output response variables considered in this investigation are cutting forces (axial, tangential and radial), torque and hole quality in terms of out-of-roundness, hole size error and surface roughness. The results show that the best cutting conditions to minimize the cutting forces and the diameter deviation are the rotational speed of 5000 rpm, tangential feed of 100 mm/min and helical pitch of 0.1 mm/rev with the assistance of the ultrasonic vibration. The ultrasonic vibration improves the performance of helical milling by decreasing the axial cutting forces.