微细电解加工用中空电极的制备

为了改进加工间隙内电解产物的排出条件和加速电解液的更新,提出了一种嵌套式微细中空电极的精确可控焊接制备工艺。仿真分析了电极的过流特性,优化了电极长度,并进行了性能测试及加工实验。通过穿丝、黏结、嵌套尺寸及位置调整和焊接工序,制备出加工段内径为65μm、外径为130μm、长3.25mm左右,后段便于装夹和连通的嵌套式中空电极。在供液压力为1.15 MPa时,其出口流速可达10m/s左右。利用制备的中空电极,开展微细孔电解加工实验,在0.5mm厚不锈钢片上加工出最小入口孔径约为157μm,出口孔径约为133μm的微细孔,并将其延伸应用于微结构加工中,铣削出了长554μm、宽160μm、深224μm的微细T型槽。实验结果表明:制备的微细中空电极有效提高了加工间隙内电解液的流动特性,且连/导通可靠、装夹方便,适用于高深宽比微结构的电解加工。

Preparation of hollow electrode used for micro ECM

To release electrolysis products and refresh electrolyte greatly within a machining gap, a welding preparation process of Micro Nested Hollow Electrode (MNHE) for micro electrochemical machining (ECM) was researched. The flow characteristics of the MNHE were simulated and analyzed to optimize its length, then, the performance test and machining experiments for the MNHE were performed. The MNHE was prepared through threading, bonding, nested size & position adjusting and welding process. The front section of the MNHE was machined into a inner diameter of 65 μm, an outer diameter of 130 μm and a length about 3.25 mm, while its rear section was convenient for clamping and connectivity. The flow rate for outlet of the MNHE could reach up to 10 m/s under fluid supplying pressure of 1.15 MPa. Finally, experiments on micro ECM holes were carried out by utilizing the prepared hollow electrode. Micro holes with the minimum inlet diameter of 157 μm and outlet diameter of 133 μm were achieved on 0.5 mm thick stainless steel. A micro T-shaped groove with 554 μm length, 160 μm width, and 224 μm depth was also milled. Experimental results indicate that the MNHE effectively improves the flow characteristics of the electrolyte within the machining gap, and it is suitable for electrochemical machining of micro structures with high aspect ratio for its easy clamp and reliable connectivity/conductivity, .