Abstract
The arc milling method has the advantages of high machining efficiency and low cost and is independent of the strength and hardness of machined materials. However, frequent electrode back-offs and the risk of workpiece burning may occur if erosion products are not removed promptly. In this study, it was found that the flushing method of the working medium had a significant impact on the machining performance of arc milling. Based on this, a novel high-efficiency compound machining method of electrical discharge and arc milling with automatic tracking of the optimal flushing direction was proposed. An automatic tracking optimizer for external working medium injection was designed to determine the optimal external flushing direction according to the feed direction. The influence of flushing methods, working mediums, and machining parameters on the machining efficiency, tool electrode wear rate, machining error, and surface integrity of titanium alloys were investigated. The results indicated that better machining performance and environmental friendliness were achieved using the compound flushing method of outer compressed air and inner deionized water. Additionally, the automatic tracking flushing method in the opposite direction of the feed direction showed superior results compared to other directions. The material removal rate with the opposite direction injection could be increased up to 1.62 times that of the same direction, and the relative electrode wear rate could be reduced by 14.76%. This novel method has broad application prospects for machining parts with difficult-to-cut materials in aerospace and military industries.
