Control Method of Machining Force and Machining Area in Tool Approach Aiming at Improving Machined Accuracy under a Constant Feed Speed Vector at the End-milling Point

A five-axis machining center is known for its synchronous control capability. We aimed to maintain the feed speed vector at the end-milling point by controlling two linear axes and a rotary axis with a five-axis machining center to improve the machined surface quality. In previous research, we suggested a method to reduce the shape error of machined workpieces (referred to as the shape error herein) considering the tool approach path determined via calculation. However, a high machining force at the start of the workpiece cutting was observed. In this research, a theoretical method to estimate the machining force is developed by using an instantaneous cutting force model, which considers the synchronized motion of two linear axes and a rotary axis of the 5MC. Subsequently, the most suitable tool approach path is determined considering the prediction of machining force and the machining area in the approach path. Therefore, both a high machining force at the start of the workpiece cutting and shape error reduction can be realized by using the proposed tool approach path.