EDM performance of Cr/Cu-based composite electrodes
EDM performance of Cr/Cu-based composite electrodes
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DOI：
10.1016/s0890-6955(02)00238-9
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发表时间：
2003-02-01
影响因子：
14
通讯作者：
Huang, FY
中科院分区：
文献类型：
--
作者：
Tsai, HC;Yan, BH;Huang, FY
用于电火花加工的电极材料通常是石墨、铜和铜合金，因为这些材料具有较高的熔化温度，以及良好的导电性和导热性。近年来，采用粉末冶金技术由特殊粉末制成的电极被用于电火花加工表面改性，以提高其耐磨性和耐腐蚀性。然而，电极通常是在高温和高压下制造的，因此制造成本很高。本文提出了一种将含树脂铜粉与铬粉混合制成工具电极的新方法。这种电极是在低压力(20兆帕)和低温度(200摄氏度)下在热装机中制造的。结果表明，采用该电极可在电火花加工后的工件表面形成表面改性层，具有显著的耐蚀性能。在最佳混合比、合适的压力和合适的加工参数(如极性、峰值电流和脉冲宽度)下，研究了材料去除速率(MRR)、电极磨损率(EWR)、表面粗糙度和重铸层厚度对电极可用性的影响。实验结果表明，在烧结压力为20 Mpa的条件下，当掺入质量分数为0wt%的铜铬时，可获得较好的磁流变性能。此外，本工作还发现，复合电极获得了比铜金属电极更高的MRR，再铸层更薄，加工表面出现的裂纹更少。此外，复合电极中的铬元素迁移到了工件上，使电火花加工后的加工表面具有良好的耐蚀性。(C)2002爱思唯尔科学有限公司。保留所有权利。
Electrode materials for electrical discharge machining (EDM) are usually graphite, copper and copper alloys because these materials have high melting temperature, and excellent electrical and thermal conductivity. The electrodes made by using powder metallurgy technology from special powders have been used to modify EDM surfaces in recent years, to improve wear and corrosion resistance. However, electrodes are normally fabricated at high temperatures and pressures, such that fabrication is expensive. This paper proposes a new method of blending the copper powders contained resin with chromium powders to form tool electrodes. Such electrodes are made at low pressure (20 MPa) and temperature (200 degreesC) in a hot mounting machine. The results showed that using such electrodes facilitated the formation of a modified surface layer on the work piece after EDM, with remarkable corrosion resistant properties. The optimal mixing ratio, appropriate pressure, and proper machining parameters (such as polarity, peak current, and pulse duration) were used to investigate the effect of the material removal rate (MRR), electrode wear rate (EWR), surface roughness, and thickness of the recast layer on the usability of these electrodes. According to the experimental results, a mixing ratio of Cu-0wt%Cr and a sinter pressure of 20 MPa obtained an excellent MRR. Moreover, this work also reveals that the composite electrodes obtained a higher MRR than Cu metal electrodes; the recast layer was thinner and fewer cracks were present on, the machined surface. Furthermore, the Cr elements in the composite electrode migrated to the work piece, resulting in good corrosion resistance of the machined surface after EDM. (C) 2002 Elsevier Science Ltd. All rights reserved.