Improved Machined Accuracy Under a Constant Feed Speed Vector at the End-Milling Point Considering Machining Force and Machining Area in Tool Approach

Abstract A five-axis machining center is known for its synchronous control capability, allowing complicated three-dimensional surfaces, such as propellers and hypoid gears, to be quickly created. 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 approach path of the tool 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 approach path of the tool 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 approach path of the tool.