Study on electrode vibration in the touch-down stage of fast electrical discharge machining drilling
Study on electrode vibration in the touch-down stage of fast electrical discharge machining drilling
复制标题
快速放电加工钻孔触地阶段电极振动研究
DOI：
10.1007/s00170-020-05820-x
复制
发表时间：
2020-07
影响因子：
3.4
通讯作者：
Zhao Wansheng
中科院分区：
文献类型：
--
作者：
Xia Weiwen;Li Zilun;Chen Mo;Zhang Yaou;Zhao Wansheng
快速电火花加工在制造业中得到了广泛的应用。在通用快速电火花钻床上加工斜孔时，触地阶段的加工效率远低于普通电火花钻床的加工效率。为了找出原因，本文利用高速摄像机对斜井钻进过程进行了观测。结果表明，管状工具电极的振动是导致加工过程不稳定、加工效率低的主要原因。振动是由放电反作用力和流体动力共同驱动的。振动扩大了间隙宽度，产生了开路脉冲，从而误导了伺服控制系统向下进给电极。过度喂食最终导致短路和随后电极的缩回。电极的反复进给和回缩导致加工效率低。在此基础上，建立了流固耦合(FSI)模型对其振动行为进行了分析。利用该模型研究了电极内部流动速度和电极自由长度的影响。研究发现，在通用快速电火花钻床上，振动是不可避免的。最后，为了减小振动的影响，提出了一种新的落地间隙伺服控制策略。该策略通过模糊规则调整参考间隙电压。实验结果表明，采用新的间隙伺服控制策略后，落地加工性能得到改善，加工效率提高了38.75%，孔口周围放电影响区面积减少了13.44%。
Fast EDM (electrical discharge machining) drilling is broadly used in the manufacturing industry. When drilling inclined holes, the machining efficiency in the touch-down stage is much lower than that of drilling normal holes for a general-purpose fast EDM drilling machine. To uncover the reasons, this paper conducted observations of inclined hole drilling processes by using a high-speed video camera. It was found that the vibration of the tubular tool electrode was the major factor that led to the unstable state, resulting in low machining efficiency. And the vibration was driven by the discharge reaction force and the hydrodynamic force. The vibration enlarged the gap width and caused open circuit pulses, which misled the servo control system to feed the electrode downward. The overfeeding eventually caused short circuits and the subsequent retraction of the electrode. The iterative feeding and retraction of the electrode resulted in low machining efficiency. Then a fluid-structure interaction (FSI) model was built to analyze the vibration behavior. The impacts of the inner flow speed and the free length of electrode were studied with the model. It was found that the vibration is inevitable on general-purpose fast EDM drilling machines. Finally, to reduce the vibration impact, a new gap servo control strategy for the touch-down stage was proposed. The strategy adjusts the reference gap voltage by fuzzy rules. Experimental results showed that with the new gap servo control strategy, the performance was improved in the touch-down stage, with the machining efficiency improved by 38.75% and the area of discharge affected zone around the hole inlet reduced by 13.44%.
登录
查看更多内容
DOI：
10.1098/rspa.1966.0187
发表时间：
1966-08
期刊：
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
影响因子：
--
作者：
R. W. Gregory;M. Païdoussis
通讯作者：
R. W. Gregory;M. Païdoussis
影响因子：
--
作者：
Mariko Tohi;T. Komatsu;M. Kunieda
通讯作者：
Mariko Tohi;T. Komatsu;M. Kunieda
DOI：
10.2526/ijem.8.51
发表时间：
2003
期刊：
International journal of electrical machining
影响因子：
--
作者：
M. Kunieda;Mariko Tohi;Y. Ohsako
通讯作者：
M. Kunieda;Mariko Tohi;Y. Ohsako
影响因子：
4.1
作者：
Kojima, A.;Natsu, W.;Kunieda, M.
通讯作者：
Kunieda, M.
DOI：
10.1016/j.procir.2017.12.064
发表时间：
2018
期刊：
Procedia CIRP
影响因子：
--
作者：
F. Klocke;S. Schneider;B. Frauenknecht;L. Hensgen;A. Klink;Kai Osswald
通讯作者：
F. Klocke;S. Schneider;B. Frauenknecht;L. Hensgen;A. Klink;Kai Osswald