Variable-parameter high-precision electrochemical discharge drilling method for 440C-Nb without recast layer
Variable-parameter high-precision electrochemical discharge drilling method for 440C-Nb without recast layer
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DOI：
10.1007/s00170-020-05885-8
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发表时间：
2020-09
期刊：
影响因子：
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通讯作者：
Jingyang Zhang;Zhengyang Xu;Chenxiang Zhang
中科院分区：
文献类型：
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作者：
Jingyang Zhang;Zhengyang Xu;Chenxiang Zhang
发动机喷嘴广泛应用于汽车领域，其制造要求具有很高的钻孔精度、一致性和良好的加工表面质量。电火花钻削是一种新型的复合加工技术，可用于加工难加工材料的小孔。电火花加工(EDM)和电解加工(ECM)可以同时进行，不仅表面质量好，而且加工速度快。然而，ECDD获得的加工精度、锥度和表面质量不能满足对发动机喷嘴喷孔提出更高要求的要求。为了提高加工精度和表面质量，提出了一种变参数电火花钻削方法。加工过程分为打孔和修形两个连续的阶段，不同的加工阶段采用不同的参数。本文采用有限元方法研究了VPECDD的加工机理，并与电火花加工、ECDD和VPECDD进行了对比实验。结果表明，该方法具有很高的加工精度和一致性，进出口直径差为0.002 mm，平均锥度为0.0004°，完全去除了再铸层。最后，验证了VPECDD适合加工高精度、无重铸层的微小孔。
Engine nozzle orifices are broadly used in the automotive field, and their manufacture entails high drilling accuracy, consistency, and excellent machined surface quality. Electrochemical discharge drilling (ECDD) is an innovative compound machining technique, which can be used to machine small holes of difficult-to-cut materials. Electrical discharge machining (EDM) as well as electrochemical machining (ECM) can occur simultaneously in ECDD, owing to which it can obtain not only good surface quality but also high processing speed. However, the machining accuracy, taper, and surface quality achieved using ECDD do not satisfy the requirements of engine nozzle orifices, which are of a higher standard. For improving the machining accuracy and surface quality, a variable-parameter electrochemical discharge drilling (VPECDD) has been proposed. The machining process is divided into two consecutive stages, including perforation and shape modification, while different parameters are used in different stages. In this study, the finite element method was applied to study the mechanism of VPECDD, and comparative experiments were performed among EDM, ECDD, and VPECDD. The results indicate that VPECDD can achieve very high machining accuracy and consistency, obtain an inlet and outlet diameter difference at 0.002 mm, maintain an average hole taper at 0.0004°, and remove the recast layer completely. Finally, it is verified that VPECDD is suitable for machining microholes with high precision and no recast layer.