Tool path optimization based on wear prediction in Electric Arc Sweep Machining

摘要

Electric arc sweep machining is a novel method for machining open channel by applying electric arc and high pressured gap flushing. In this method, a shaped and non-rotating tool sweeps on the workpiece surface to erode a layer by scanning machining area following a predefined geometric path. In this condition, tool wear changes around the periphery depending on feeding direction. Therefore, a proper tool path planning is a key factor to improve the machining efficiency and quality. To cover this issue, in this research a procedure is proposed for selecting the best tool pathway for groove machining. Tool path planning is based on uniform bottom erosion mechanism during machining which occurs between end surface of tool electrode and workpiece. For this reason, tool wear prediction is carried out theoretically and then, effects of tool pathway on tool erosion are studied. Finally, tool pathway is optimized to get a uniform tool wear and machined surface. Based on tool wear mechanism, material erosion starts from the edge facing the feeding direction and then expands to other regions in the bottom surface of the tool electrode. Therefore, to achieve a uniform tool wear and a smooth surface, tool feeding direction should change in specific moments to transfer tool erosion to other edges. To verify theoretical findings, a set of experiment is conducted. Experimental results show that optimized tool pathway can both improve MRR and reduce TWR efficiently. Moreover, fabricating a groove by implementing proposed pathway strategies can improve machined surface quality by distributing tool wear uniformly.