Effect of Pulse Conditions on Machining Characteristics in Bipolar-Pulse Electrochemical Machining of Cemented Carbide
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Published:2023-11-05
Issue:6
Volume:17
Page:583-593
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ISSN:1883-8022
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Container-title:International Journal of Automation Technology
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language:en
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Short-container-title:IJAT
Author:
Koyano Tomohiro1ORCID, Hokin Taisei2, Furumoto Tatsuaki3ORCID
Affiliation:
1. Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan 2. Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan 3. Advanced Manufacturing Technology Institute (AMTI), Kanazawa University, Kanazawa, Japan
Abstract
Electrochemical machining was performed on two cemented carbides with different compositions using unipolar and bipolar short-pulse voltages to investigate the effects of the composition and pulse conditions on the machining characteristics. In the case of cemented carbides with high cobalt and low tungsten carbide (WC) contents, machining progressed even when a unipolar voltage was used. This is believed to be due to the dissolution of the binder, that is, Co, which causes the WC and WO3 particles to drop out. Machining progressed more easily when a bipolar voltage was used than when a unipolar voltage was used. This is attributed to the effective removal of WO3. The unevenness of the machined surface was also reduced with bipolar voltage. The negative pulse duration had to be sufficiently but appropriately long, because too long a duration increased the wear of the tool electrode. Even when bipolar pulse voltages were used, similar to the machining of general materials, a shorter positive pulse duration resulted in more precise machining. However, in the case of cemented carbide with low Co and high WC contents, the removal did not progress when a unipolar pulse voltage was applied. On the other hand, the machining progressed when a bipolar voltage was applied. However, if the positive pulse duration was excessively long, the amount of removal decreased. This is believed to be because the longer positive pulse duration increased the amount of WO3 generated, thereby inhibiting the current flow. Therefore, it is necessary to set an appropriate positive pulse duration to avoid the excessive production of WO3.
Publisher
Fuji Technology Press Ltd.
Subject
Industrial and Manufacturing Engineering,Mechanical Engineering
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