Improvement of Machining Accuracy by Correcting Tool Deflection Based on Identification of Actual Feed Speed Associated with Acceleration/Deceleration Control of Machine Tool

When an NC machine tool is utilized during the machining process, accclcration/dccclcration control is adapted for axes motions of the machine tool. Simultaneous accclcration/dccclcration controls are applied to multiple axes to achieve smooth motion of the machine tool axes. However, such a technique does not accurately realize the designated motion speeds of the axes and cutting tool paths. In addition, the deflection of the cutting tool owing to the cutting force further increases machining error. Therefore, the actual tool paths must be identified and be corrccted according to cutting-tool deflection to improve machining accuracy. The actual feed speed, which is controlled by the accclcration/dccclcration of the cutting tool at each point on the tool path, must be identified to predict the cutting force precisely and estimate the tool deflection accurately. In this study, model equations were established to estimate the feed speed of the machine tool axes. The cutting force applied to an end-mill and a ball-cnd-mill could be precisely estimated using the estimated feed speed of the cutting tool. Then, the estimated cutting force was applied to predict the tool deflection accurately. Consequently, the tool paths were corrected based on the predicted tool dcflcction for high-accuracy machining. The effectiveness of this correction technique was verified through machining tests.