Parametric study and multicharacteristic optimization of rotary turning process assisted by longitudinal ultrasonic vibration

چکیده مقاله

Turning with rotar y tool is a newly developed alternative of the conventional turning process in which cutting edge of a round inser t rotates about its axis, so that a continuously indexed cutting edge is fed into the cutting zone . In the present study, a longitudinal high-frequency vibration was superimposed to the rotar y tool to analyze the cutting force and surface roughness of AA7075 during or thogonal cutting. However, due to contribution of wide ranges of factors in the vibrator y-rotar y turning process, the selection of optimal parameter setting is a challenge that is faced with this process. In the present work, an attempt was made to simultaneously minimize machining force ( Fz) and surface roughness ( Ra) through selection of the optimal setting of cutting velocity, feed rate , tool rotar y speed in rotar y turning, and vibrator y-rotar y turning operations. Here, grey relational analysis was used to find the optimal parameter setting in rotar y turning and vibrator y-rotar y turning processes, separately. Then the obtained solutions were compared. Results indicated that applying axial vibration to the rotar y tool turning significantly reduced both surface roughness and cutting force . From the optimization by the grey relational analysis method, it was obtained that for both rotar y turning and vibrator y-rotar y turning operations, setting of 4 m/min cutting velocity, 220 r/min tool rotar y speed, 0.08 mm/rev feed rate , and 0.3 mm depth of cut are the most-optimal solutions that causes minimum Fz and Ra, simultaneously. Also, the vibrator y-rotar y turning process had higher values of grey relational grade than the rotar y turning process that implies outperformance of the vibrator y-rotar y turning with respect to the rotar y turning process. The obtained results were then verified, compared, and discussed based on the mechanics of turning process.