マシニングセンタにおけるボールねじ熱膨張誤差の自動補正

抄録

Thermal expansion of the ball screw in semi-closed loop type machining centers directly introduces positioning errors along the travel axis. The purpose of this study is to develop an automatic compensation method for the expansion of the ball screw using the thermal expansion detector installed near the NC zero point. The thermal behaviour of the ball screw of the horizontal machining center under the various driving conditions was measured to examine the effectiveness of this compensating method. From these results, the thermal expansions of the ball screw along the travel axis were approximated by a linear function of the distance from the ball screw support, and thereby the positioning accuracy could be maintained to better than ±3μm while using this compensation.