Improving Motion Accuracy of Circular Arc Interpolation Cutter Paths of Machining Center via Reverse Compensation Based on Simulation Result

In precision machining of complex workpiece contours on a machining center (MC), circular arc interpolation cutter paths are often employed. During this process, some motion errors arise in the actual cutter path due to the NC acceleration/deceleration (Acc/Dec) processing to interpolation segments and the position servo control with drive axes. As a result, the corresponding profile deviations are introduced into the machined workpiece contours. In general, the motion error increases more remarkably as the commanded feed rate is higher. From the MC user’s point of view, the authors have developed a practical approach to effectively and conveniently simulate the motion trajectory of cutter paths caused by the Acc/Dec processing and the position servo control for a target MC. As a further exploration, this study examines in detail the possibility and practicality of using the developed method to improve the motion accuracy of circular arc interpolation cutter paths without reducing the feed rate, through reverse compensating the cutter path based on the simulation results of the motion trajectory. Firstly, a concise procedure is integrated into the previously developed simulation algorithm to deal with the effects of the maximum acceleration limitation with driving axes and block processing time installed in the NC system of MC on the cutter path motion trajectory. Next, some simple and practical rules are established to automatically generate the reverse compensation cutter path based on the simulation results. The effectiveness of the reverse compensation method has been sufficiently demonstrated through the verification experiments of practical machining for two types of planar cam contours performed in different feed rates. Comparing with other reverse compensation methods published, the method proposed in this study doesn’t require conducting any actual before-hand cutting experiments or introducing a new NC system with special functions into the MC, and therefore it can be considered to be highly valuable from the perspective of practicality and convenience.