单向走丝电火花线切割拐角切割轨迹策略的研究
摘要
电火花线切割加工技术是一种广泛应用于模具、高级陶瓷与现代复合材料等领域的关键加工技术。随着市场对加工工件质量的要求不断提高,应用于单向走丝电火花线切割加工设备的新技术、新工艺等推陈出新,展现了很高的技术水准。一直以来拐角加工精度技术便是线切割加工中的难题与关键技术。在此背景下,本文研究了一种应用于单向走丝线切割粗加工阶段的拐角轨迹策略,旨在通过在拐角处应用规划的数控轨迹以提高拐角加工形状精度。
本文建立了电极丝滞后量与电极丝运动速率的关系。在一定条件下,认为电极丝滞后量与电极丝运动速率满足正比例的关系。应用电极丝滞后量与电极丝运动速率两者的关系,并根据电极丝运动轨迹与数控系统运动轨迹的几何关系模型确定了电极丝运动方向,实现了对拐角处电极丝运动轨迹的仿真并针对不同类型的拐角提出了相应的拐角轨迹策略以提高加工拐角的形状精度。在完成拐角轨迹策略过程中借鉴了优化设计的思想。主要完成了直线与直线拐角与部分直线与圆弧拐角的轨迹策略研究。由仿真结果显示,采用拐角轨迹策略生成的电极丝轨迹与拐角轮廓间的误差减小。
设计了正交试验以建立电极丝滞后量与部分主要加工参数之间的关系,并对实验结果进行了回归分析。通过验证实验比较了是否采用拐角轨迹策略所切割的拐角轮廓。由实验结果知,应用拐角轨迹策略后切割的拐角形状精度有一定提升,拐角轮廓外边缘形状精度改善明显,内边缘形状精度改善较外边缘稍差。为了使拐角轨迹策略可视化,开发了应用拐角轨迹策略的软件。该软件的输入输出均为数控代码,拐角处的仿真轨迹与规划轨迹均可在软件中显示。
WEDM has been gaining wide acceptance in modern tooling applications and evolved as one of the most promising alternatives for the machining of the advanced ceramics and modern composite materials. As the market demand for improving the quality of the workpiece, new technologies and processes were applied in WEDM, which demonstrated a high level of technology. Improving the corner geometrical accuracy was difficult and important. Path strategies applied in rough cutting were developed to reduce geometrical inaccuracy of corner in this paper.
This paper established the relationship between the distance of wire electrode lag and the velocity of the wire electrode. Under certain conditions, supposed that the distance of wire electrode lag and the velocity of wire electrode to meet the direct proportion relationship in this paper. Based on the relationship between the wire lag and the velocity of wire and the geometrical model between the wire electrode path and the NC path, a simulation path of the wire of cutting corner was worked out and the path strategies corresponding to different types of corner were proposed to improve the corner shape precision. In the development of path strategies applied in the optimization design ideas. Path strategies for the corner contained two lines and the corner contains line and circle were developed. The simulation results revealed that the error between the wire path and the corner contour reduced.
To establish the relationship between the distance of wire lag and the main influencing factors, a test based on Taguchi method was carried out and the test results were analyzed through regression analysis. The shapes of corner were compared by using path strategies for the corner or not. The experimental results demonstrated that the contour accuracy of the corner improved by using the path strategy for the corner. To visualize the corner path strategy, software about corner path strategy was developed. The input and out of the software both were NC codes. The simulation path and the strategy path were both displayed on the screen.
本文建立了电极丝滞后量与电极丝运动速率的关系。在一定条件下,认为电极丝滞后量与电极丝运动速率满足正比例的关系。应用电极丝滞后量与电极丝运动速率两者的关系,并根据电极丝运动轨迹与数控系统运动轨迹的几何关系模型确定了电极丝运动方向,实现了对拐角处电极丝运动轨迹的仿真并针对不同类型的拐角提出了相应的拐角轨迹策略以提高加工拐角的形状精度。在完成拐角轨迹策略过程中借鉴了优化设计的思想。主要完成了直线与直线拐角与部分直线与圆弧拐角的轨迹策略研究。由仿真结果显示,采用拐角轨迹策略生成的电极丝轨迹与拐角轮廓间的误差减小。
设计了正交试验以建立电极丝滞后量与部分主要加工参数之间的关系,并对实验结果进行了回归分析。通过验证实验比较了是否采用拐角轨迹策略所切割的拐角轮廓。由实验结果知,应用拐角轨迹策略后切割的拐角形状精度有一定提升,拐角轮廓外边缘形状精度改善明显,内边缘形状精度改善较外边缘稍差。为了使拐角轨迹策略可视化,开发了应用拐角轨迹策略的软件。该软件的输入输出均为数控代码,拐角处的仿真轨迹与规划轨迹均可在软件中显示。
WEDM has been gaining wide acceptance in modern tooling applications and evolved as one of the most promising alternatives for the machining of the advanced ceramics and modern composite materials. As the market demand for improving the quality of the workpiece, new technologies and processes were applied in WEDM, which demonstrated a high level of technology. Improving the corner geometrical accuracy was difficult and important. Path strategies applied in rough cutting were developed to reduce geometrical inaccuracy of corner in this paper.
This paper established the relationship between the distance of wire electrode lag and the velocity of the wire electrode. Under certain conditions, supposed that the distance of wire electrode lag and the velocity of wire electrode to meet the direct proportion relationship in this paper. Based on the relationship between the wire lag and the velocity of wire and the geometrical model between the wire electrode path and the NC path, a simulation path of the wire of cutting corner was worked out and the path strategies corresponding to different types of corner were proposed to improve the corner shape precision. In the development of path strategies applied in the optimization design ideas. Path strategies for the corner contained two lines and the corner contains line and circle were developed. The simulation results revealed that the error between the wire path and the corner contour reduced.
To establish the relationship between the distance of wire lag and the main influencing factors, a test based on Taguchi method was carried out and the test results were analyzed through regression analysis. The shapes of corner were compared by using path strategies for the corner or not. The experimental results demonstrated that the contour accuracy of the corner improved by using the path strategy for the corner. To visualize the corner path strategy, software about corner path strategy was developed. The input and out of the software both were NC codes. The simulation path and the strategy path were both displayed on the screen.
引文
[1]朱宁,叶军,韩福柱等.电火花线切割加工技术及其发展动向[J].电加工与模具, 2010, (S1):53-59,63.
[2]叶军.数控低速走丝电火花线切割加工技术及市场发展分析[J].电加工与模具,2005,(S1):13-16.
[3]李明辉.电火花线切割技术的研究现状及发展趋势[J].模具技术,2003,(01):51-53,61.
[4]张健.电火花线切割拐角加工控制方法研究[J].硅谷,2010(23):100,185.
[5]荆晓雪.电火花线切割拐角加工精度的实时预测系统与控制[D].北京:北京邮电大学,2008.
[6]李明辉.电火花线切割技术的研究现状及发展趋势[J].模具技术,2002,(06):49-52.
[7] Magara T, Yatomi T, Yamada H, et al. Study on machining accuracy in WEDM, part I—improvement of machining accuracy of corner parts in rough-cutting (in Japanese) [J]. Journal of Japan Society of Electrical-Machining Engineers, 1991,25 (49):23-32.
[8] Sanchez J A, Cabanes I, Lamikiz A,et al. Development of optimum electrodischarge machining technology for advanced ceramics[J]. Inter. J. Adv. Manuf. Technol, 2001,18 (12):897–905.
[9] Sanchez J A, Rodil J L, Herrero A. On the influence of cutting speed limitation on the accuracy of wire-EDM corner-cutting[J]. Journal of Materials Processing Technology, 2007(182):574-579.
[10] Puri A B, Bhattacharyya B. Modeling and analysis of the wire-tool vibrationin wire-cut EDM[J]. Journal of Materials Processing Technology, 2003(141):295-301.
[11] Puri A B, Bhattacharyya B. An analysis and optimisation of the geometrical inaccuracy due to wire lag phenomenon in WEDM[J]. International Journal of Machine Tools & Manufacture, 2003(43):151-159.
[12]朱宁,许庆平,朱伟根等.低速走丝电火花线切割加工工艺研究[J].电加工与模具,2008(03):59-63.
[13] Hsue W J, Liao Y S, Lu S S. Fundamental geometry analysis of wire electrical discharge machining in corner cutting[J]. International Journal of Machine Tools & Manufacture,1999 (39) :651–667.
[14] Hsue W J, Liao Y S, Lu S S. A Study of Corner Control Strategy of Wire-EDM Base on Quantitative MRR Analysis[J]. International Journal of Electrical Machining, 1999(4):33-39.
[15] Yan M T, Liao Y S. Monitoring and self-learning fuzzy control for wire rupture prevention in wire electrical discharge machining[J]. International Journal of Machine Tools & Manufacture ,1996, 36 (3):339–353.
[16] Liao Y S, Woo J C. Design of a fuzzy controller for the adaptive control of WEDM process[J]. International Journal of Machine Tools & Manufacture, 2000(40):2293-2307.
[17] Hsue A W. Improvement of Wire-EDM Finishing Processes through AdaptiveFuzzy Logic Control Algorithm[C]. Materials Science Forum, 2008(594):407-414.
[18] Lin C, Chung I, Huang H. Improvement of machining accuracy by fuzzy logic at corner parts for wire-EDM[J]. Fuzzy Sets and Systems, 2001(122):499-511.
[19] Sarkar S, Mitra S, Gomes I K. Modeling and optimization of wire electrical discharge machining in single pass cutting operation[C]. Proceedings of the International Conference on Mechanical Engineering, 2005. ICME2005:28-30.
[20] Chakraborty Shankar S K G. Optimization of multiple responses for WEDM processes using weighted principal components[J]. Int J Adv Manuf Technol, 2009(40):1102-1110.
[21]周晓铭,陶俊才.基于BP神经网络的线切割工艺指标预测[J].微计算机信息,2008,24(3-1):232-233.
[22]苏军,王斌.基于神经网络的电火花线切割工艺目标建模[J].应用光学,2009(5):743-746.
[23] Dekeyser W L, Snoeys R. Geometric accuracy of wire-EDM[C]. Proceedings of ISEM-9, 1989: 226–232.
[24] Obara H, Abe M, Ohsumi T. Control of wire breakage during wire EDM[J]. Int. J. Electr. Machining, 1999(4):53-58.
[25]颜木田,庄宗仁.線切割放電加工隅角粗加工軌跡補償策略之研究[J].国立台湾大学「台大工程」学刊2003(87):109-117.
[26] Sarkar S, Sekn M, Mitra S. A novel method of determination of wire lag for enhanced profile accuracy in WEDM[J]. Precision Engineering, 2011(35):339-347.
[27] Sanchez J A, Lacalle L N L, Lamikiz A. A computer-aided system for the optimization of the accuracy of the wire electro-discharge machining process[J]. International Journal of Comp Integrated Manufacturing, 2004. 17(5):413-420.
[28]周晓光,荆晓雪,韩福柱.电火花线切割拐角加工精度的实时预测[J].电加工与模具,2008(03):27-30.
[29] Han F Z, Zhang J, Soichiro I. Corner error simulation of rough cutting in wire EDM[J]. Precision Engineering, 2007(31):331-336.
[30]韩福柱,陶春生,张洁.慢走丝电火花线切割加工精度的仿真研究[C]//第11届全国特种加工学术会议专辑.北京:工业出版社,2005:220-223.
[31]刘志东,刘其荣,袁家斌.高速走丝电火花线切割拐角加工研究[J].电加工与模具,1991(04):6-10.
[32]陈传伟.高速走丝线切割加工角部保护措施[J].电加工与模具,2001(05):45-46.
[33]周坚,余承业.线切割尖角切割精度控制研究[J].航空制造技术,1991(05):9-11.
[34]高秀兰,浅析线切割加工中存在的问题及对策[J].模具工业,2002(10):56-59.
[35] Dauw D F, Beltrami I. High-precision wire-EDM by online wire position control[C]. Annals of the CIRP, 1994,43 (1):193–197.
[36] Beltrami I, Bertholds A, Dauw D. A simpli?ed post process for wire cut EDM[J]. Journal of Material Processing Technology, 1996(58):385–389.
[37] Yan M T, Huang P. Accuracy improvement of wire-EDM by real-time wiretension[J]. International Journal of Machine Tools & Manufacture, 2004(44):807-814.
[38]韩福柱.火花线切割加工技术的发展动态[C]//第11届全国特种加工学术会议专辑.北京:工业出版社,2005:25-33.
[39]杨立军,党新安.线切割加工中拐角误差的分析[J].制造技术与机床,2004(11):72-74.
[40]狄士春,于滨,赵万生.国外电火花线切割加工技术最新进展[J].电加工与模具,2003(3):12-16.
[41]迟关心,周晶洁,黄瑞宁等.微细电火花线切割加工误差分析[J].现代制造工程,2006(6):37-40.
[42]刘晋春,白基成,郭永丰.特种加工[M].第5版.北京:机械工业出版社,2008:15.
[43]李云雁,胡传荣.试验设计与数据处理[M].北京:化学工业出版社,2005:64.
[44]何晓群,刘文卿.应用回归分析[M].北京:中国人民大学出版社,2001:131,153.
[2]叶军.数控低速走丝电火花线切割加工技术及市场发展分析[J].电加工与模具,2005,(S1):13-16.
[3]李明辉.电火花线切割技术的研究现状及发展趋势[J].模具技术,2003,(01):51-53,61.
[4]张健.电火花线切割拐角加工控制方法研究[J].硅谷,2010(23):100,185.
[5]荆晓雪.电火花线切割拐角加工精度的实时预测系统与控制[D].北京:北京邮电大学,2008.
[6]李明辉.电火花线切割技术的研究现状及发展趋势[J].模具技术,2002,(06):49-52.
[7] Magara T, Yatomi T, Yamada H, et al. Study on machining accuracy in WEDM, part I—improvement of machining accuracy of corner parts in rough-cutting (in Japanese) [J]. Journal of Japan Society of Electrical-Machining Engineers, 1991,25 (49):23-32.
[8] Sanchez J A, Cabanes I, Lamikiz A,et al. Development of optimum electrodischarge machining technology for advanced ceramics[J]. Inter. J. Adv. Manuf. Technol, 2001,18 (12):897–905.
[9] Sanchez J A, Rodil J L, Herrero A. On the influence of cutting speed limitation on the accuracy of wire-EDM corner-cutting[J]. Journal of Materials Processing Technology, 2007(182):574-579.
[10] Puri A B, Bhattacharyya B. Modeling and analysis of the wire-tool vibrationin wire-cut EDM[J]. Journal of Materials Processing Technology, 2003(141):295-301.
[11] Puri A B, Bhattacharyya B. An analysis and optimisation of the geometrical inaccuracy due to wire lag phenomenon in WEDM[J]. International Journal of Machine Tools & Manufacture, 2003(43):151-159.
[12]朱宁,许庆平,朱伟根等.低速走丝电火花线切割加工工艺研究[J].电加工与模具,2008(03):59-63.
[13] Hsue W J, Liao Y S, Lu S S. Fundamental geometry analysis of wire electrical discharge machining in corner cutting[J]. International Journal of Machine Tools & Manufacture,1999 (39) :651–667.
[14] Hsue W J, Liao Y S, Lu S S. A Study of Corner Control Strategy of Wire-EDM Base on Quantitative MRR Analysis[J]. International Journal of Electrical Machining, 1999(4):33-39.
[15] Yan M T, Liao Y S. Monitoring and self-learning fuzzy control for wire rupture prevention in wire electrical discharge machining[J]. International Journal of Machine Tools & Manufacture ,1996, 36 (3):339–353.
[16] Liao Y S, Woo J C. Design of a fuzzy controller for the adaptive control of WEDM process[J]. International Journal of Machine Tools & Manufacture, 2000(40):2293-2307.
[17] Hsue A W. Improvement of Wire-EDM Finishing Processes through AdaptiveFuzzy Logic Control Algorithm[C]. Materials Science Forum, 2008(594):407-414.
[18] Lin C, Chung I, Huang H. Improvement of machining accuracy by fuzzy logic at corner parts for wire-EDM[J]. Fuzzy Sets and Systems, 2001(122):499-511.
[19] Sarkar S, Mitra S, Gomes I K. Modeling and optimization of wire electrical discharge machining in single pass cutting operation[C]. Proceedings of the International Conference on Mechanical Engineering, 2005. ICME2005:28-30.
[20] Chakraborty Shankar S K G. Optimization of multiple responses for WEDM processes using weighted principal components[J]. Int J Adv Manuf Technol, 2009(40):1102-1110.
[21]周晓铭,陶俊才.基于BP神经网络的线切割工艺指标预测[J].微计算机信息,2008,24(3-1):232-233.
[22]苏军,王斌.基于神经网络的电火花线切割工艺目标建模[J].应用光学,2009(5):743-746.
[23] Dekeyser W L, Snoeys R. Geometric accuracy of wire-EDM[C]. Proceedings of ISEM-9, 1989: 226–232.
[24] Obara H, Abe M, Ohsumi T. Control of wire breakage during wire EDM[J]. Int. J. Electr. Machining, 1999(4):53-58.
[25]颜木田,庄宗仁.線切割放電加工隅角粗加工軌跡補償策略之研究[J].国立台湾大学「台大工程」学刊2003(87):109-117.
[26] Sarkar S, Sekn M, Mitra S. A novel method of determination of wire lag for enhanced profile accuracy in WEDM[J]. Precision Engineering, 2011(35):339-347.
[27] Sanchez J A, Lacalle L N L, Lamikiz A. A computer-aided system for the optimization of the accuracy of the wire electro-discharge machining process[J]. International Journal of Comp Integrated Manufacturing, 2004. 17(5):413-420.
[28]周晓光,荆晓雪,韩福柱.电火花线切割拐角加工精度的实时预测[J].电加工与模具,2008(03):27-30.
[29] Han F Z, Zhang J, Soichiro I. Corner error simulation of rough cutting in wire EDM[J]. Precision Engineering, 2007(31):331-336.
[30]韩福柱,陶春生,张洁.慢走丝电火花线切割加工精度的仿真研究[C]//第11届全国特种加工学术会议专辑.北京:工业出版社,2005:220-223.
[31]刘志东,刘其荣,袁家斌.高速走丝电火花线切割拐角加工研究[J].电加工与模具,1991(04):6-10.
[32]陈传伟.高速走丝线切割加工角部保护措施[J].电加工与模具,2001(05):45-46.
[33]周坚,余承业.线切割尖角切割精度控制研究[J].航空制造技术,1991(05):9-11.
[34]高秀兰,浅析线切割加工中存在的问题及对策[J].模具工业,2002(10):56-59.
[35] Dauw D F, Beltrami I. High-precision wire-EDM by online wire position control[C]. Annals of the CIRP, 1994,43 (1):193–197.
[36] Beltrami I, Bertholds A, Dauw D. A simpli?ed post process for wire cut EDM[J]. Journal of Material Processing Technology, 1996(58):385–389.
[37] Yan M T, Huang P. Accuracy improvement of wire-EDM by real-time wiretension[J]. International Journal of Machine Tools & Manufacture, 2004(44):807-814.
[38]韩福柱.火花线切割加工技术的发展动态[C]//第11届全国特种加工学术会议专辑.北京:工业出版社,2005:25-33.
[39]杨立军,党新安.线切割加工中拐角误差的分析[J].制造技术与机床,2004(11):72-74.
[40]狄士春,于滨,赵万生.国外电火花线切割加工技术最新进展[J].电加工与模具,2003(3):12-16.
[41]迟关心,周晶洁,黄瑞宁等.微细电火花线切割加工误差分析[J].现代制造工程,2006(6):37-40.
[42]刘晋春,白基成,郭永丰.特种加工[M].第5版.北京:机械工业出版社,2008:15.
[43]李云雁,胡传荣.试验设计与数据处理[M].北京:化学工业出版社,2005:64.
[44]何晓群,刘文卿.应用回归分析[M].北京:中国人民大学出版社,2001:131,153.