微小孔螺旋管电极电火花-电解组合加工数值模拟及试验分析

Numerical simulation and experimental analysis on micro-holes processing by helical tube electrode

为提高狭小间隙产物排出和加快电解液更新,采用螺旋管电极正反转匹配内外冲液方式进行电火花(EDM)电解(ECM)组合加工。在电火花加工快速穿孔阶段,内冲液方式匹配电极顺时针旋转可增加间隙流场扰动,进而加快电蚀颗粒排出速度;在电解扩孔阶段,外冲液方式匹配电极逆时针旋转提高狭小间隙内电解液更新速度,进而保证孔壁电解效果。利用流场仿真证明螺旋管电极提高了间隙最大流速15.6%。实验验证螺旋管电极可以减小孔锥度至0.008,加工效率提高了25%。最终优化参数为冲液压力4 MPa和电极转速460 r/min。

The combined method of electrical discharge machining(EDM)and electrochemical machining(ECM)of internal and external flushing with the rotating of the helical tube electrode was used to improve the removal of narrow gap products and accelerate the electrolyte renewal.In the EDM stage,the internal flushing method matched the clockwise rotation of the electrode to increase the gap flow field disturbance,thereby accelerating the removal rate of the products.In the ECM stage,the counter-clockwise rotation of the external flushing matching electrode could increase the electrolyte renewal speed in the narrow gap,ensuring the electrolysis performance of the hole wall.The flow field simulation for the helical tube electrode confirmed the increased gap maximum flow rate by 15.6%.It was verified by experiments that the helical electrode could reduce the taper by 0.008,and the processing efficiency was improved by 25%.The final optimization parameters were a flush pressure of 4 MPa and a tool electrode speed of 460 r/min.