电极丝失稳临界摩擦力及临界转速研究
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摘要
微细孔电火花加工过程中,电极丝与导向器间的摩擦力控制不合理极易导致电极丝断丝和电极丝振动加剧,影响加工效率和加工精度。将电极丝简化为Euler-Bernoulli梁,建立电极丝受压失稳的临界摩擦力计算模型和电极丝固有模态计算分析模型。利用建立的通用模型进行分析,得到直径为0.19mm的钨电极丝避免断丝的临界摩擦力,并结合有限元方法分析电极丝长度及摩擦力对电极丝横向振动固有频率的影响规律,进一步确定了微量进给旋转轴的临界转速。该结论可从理论上指导电火花孔加工过程中工艺参数的选择和优化。
The unproperly control of friction force between the electrode wire and director tends to break the electrode wire and exacerbate the vibration of electrode wire in the electrical discharge micro-hole machining.In the light of this problem,the electrode wire is simplified to the Euler-Bernoulli beam to establish the calculation model of the critical friction force and analysis model of its inherent mode.The law between the electrode wire′s length and the friction′s influence on the natural frequency of the transverse vibration of the electrode wire is analyzed by using the finite element method.The critical frictional force of electrode wire with a diameter of 0.19 mm is calculated.The critical speed of the micro-feed rotary axis is further determined.The conclusion can be used to guide the selection and optimization of process parameters in the process of electrical discharge micro-hole machining.
The unproperly control of friction force between the electrode wire and director tends to break the electrode wire and exacerbate the vibration of electrode wire in the electrical discharge micro-hole machining.In the light of this problem,the electrode wire is simplified to the Euler-Bernoulli beam to establish the calculation model of the critical friction force and analysis model of its inherent mode.The law between the electrode wire′s length and the friction′s influence on the natural frequency of the transverse vibration of the electrode wire is analyzed by using the finite element method.The critical frictional force of electrode wire with a diameter of 0.19 mm is calculated.The critical speed of the micro-feed rotary axis is further determined.The conclusion can be used to guide the selection and optimization of process parameters in the process of electrical discharge micro-hole machining.
引文
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[2]陈云信,吴福明,邓成文.基于ANSYS的电极丝振动现象研究[J].电加工与模具,2006(4):26-28.Chen Yunxin,Wu Fuming,Deng Chengwen.Deliberated wire electrode vibration based on ANSYS[J].Electromachining and Mould,2006(4):26-28.(in Chinese)
[3]杨大勇,伏金娟.电火花成形加工技术及其发展动向[J].航空制造技术,2010(5):43-46.Yang Dayong,Fu Jinjuan.Development of electrical discharge forming technology[J].Aeronautical Manufacturing Technology,2010(5):43-46.(in Chinese)
[4]刘建勇,杨大勇,郭妍,等.精密微细倒锥孔电火花加工机床机械系统的研究[J].电加工与模具,2013(5):54-58.Liu Jianyong,Yang Dayong,Guo Yan,et al.Research on the mechanical system of EDM machine maching for the precision reverse taper microhole[J].Electromachining and Mould,2013(5):54-58.(in Chinese)
[5]贾志新,滕向阳,闫凯,等.立式回转电火花线切割加工新技术[J].机械工程师,2006(5):19-20.Jia Zhixin,Teng Xiangyang,Yan Kai,et al.Novel technology of vertical wire electrical discharge machining with rotation wire[J].Mechanical Engineer,2006(5):19-20.(in Chinese)
[6]Wang Min,Zhou Qiang,Liu Jianyong.Geometric and motion error model and precision analysis of Multiaxial EDM[J].Applied Mechanics and Materials,2015,742:631-635.
[7]刘鸿文.材料力学Ⅰ[M].4版.北京:高等教育出版社,2004:38-50,301-337.
[8]吴天行,华宏星.机械振动[M].北京:清华大学出版社,2014:29-36,45-55.
[9]Koch O,Ehrfeld W,Michel F,et al.Recent progress in micro-electro dishcharge machining(part I):technology[C]∥Proceedings of the 13th International Symposium for Electrod Machining.[S.l.]:World Manufacturing Engineering&Market,2002:29-36.
[10]Soichi Ibaraki,Chiaki Oyama,Hisashi Otsubo.Construction of an error map of rotary axes on a five-axis machining center by static R-test[J].International Journal of Machine Tools Manufacturer,2011(51):190-200.
[11]Konig W,Klonche F,Lenzen R.The electrical machining process-what demands will they face in the future[J].International Journal of Electrical Machining,1996,1(1):1-8.