微细电火花铣削加工插补技术与轨迹规划研究
|
摘要
在工业装备中微细结构日益增多,微细结构加工需求随之增大。微细电火花铣削加工技术在微细结构加工方面具有极大的技术潜力和优势,具有材料适用范围广、无宏观切削力等特性。但是,微细电火花铣削加工技术也存在着诸多技术难题：微小的放电能量和放电间隙造成放电状态不稳定,加工过程中易出现短路现象,加工过程难于准确控制,加工效率较低；由于加工过程中电极不断损耗,精确的电极补偿与合理的轨迹规划相结合才能完成微小三维结构加工。因此,解决微细电火花铣削加工中的短路问题,并且进行精确的电极补偿与轨迹规划是微细电火花铣削加工方法中的关键问题。
针对微细电火花铣削加工过程中出现的电极与工件间的短路现象,通过分析微细电火花铣削加工特性和短路产生原因,本文提出了一种基于正方形约束的插补算法和基于动态周期的进给控制方法,并为该插补算法所产生的插补数值设计了基于位模式的存储结构。该插补算法与进给模式相结合,充分利用了微细电火花铣削加工的特性,解决了加工过程中出现的短路问题。在解决短路问题的基础上,本文进行电极补偿实验和三维结构加工的轨迹规划研究。以等量补偿和分层铣削加工理论为基础,通过工艺实验确定了电极补偿参数,并将电极补偿与三维结构轨迹规划相结合,设计出三维结构的加工轨迹,实现自动补偿加工。基于以上研究,最终开发出了微细电火花铣削加工机床控制软件,将基于正方形约束的插补算法与动态周期的进给控制方法集成于系统中,并将铣削加工过程中的加工状态、电极补偿参数、手动控制和加工参数调整等集成于系统中,同时对运动控制卡中的PID控制系统进行参数调节,满足伺服运动的灵敏性和精确度要求,实现了对机床三轴联动的精确控制。
通过实验验证,本文提出的基于正方形约束的插补算法和动态周期进给控制模式,以及本文开发的微细电火花铣削加工控制软件,能够在微细电火花铣削加工过程中避免电极与工件之间发生短路,将微细电火花铣削加工效率提高了30%。在三维微小结构加工实验中,利用本文确定的补偿参数和轨迹,实现了分层铣削加工过程中电极自动补偿,能够一次性加工完成三维微小结构。
There are more and more Mico-constructs in industry equipment. It demands more machining methods. Mico-EDM milling has great advantage and potential ability to machine Mico-constructs. Micro-EDM milling is a kind of manufacturing method of non-contact between tool and workpiece. It can machine many kinds of material and no cut force. But some weak points such as discharge energy, discharge distance and unstable discharge state make it hard to control the machining process and to get effective method. It is also difficult to meet the accuracy for the electrode corrosion. The electrode compensation is important to the accuracy. Therefore, it is necessary to solve short circuit and make accurate compensation and path plan.
This paper present a new interpolation method based on square constraint which can preclude short circuit in Mcro-EDM milling. There is also a new storage structure for the NC code. Based on the new interpolation method, this paper researched the feed method and present available period feed method. Meanwhile, a lot of machining experiments have been done to find the optimal electrical parameter. In the machining experiments, the new interpolation method combined with the new feed method can solve the short circuit problem and enhance the efficiency largely. The optimal electrical parameter can enhance the efficiency more. Based on the compensation parameter, this paper researched the3D' path plan and designs3D path with automatic compensation. Based on the researches above, this paper developed a numerical control software for Mico-EDM milling machine. The software contains control method, machining state display, compensation method, manual control and parameter adjustment. It can control movement of motors and platform to meet the accuracy through PMAC.
In the experiments, the software can connect well with hardware and the accuracy can meet the design requirement. As no short circuit in the machining process, the machining efficiency was improved by30%. Also, using this system, the micro-3D structure can be machined in one time with automatic compensation.
针对微细电火花铣削加工过程中出现的电极与工件间的短路现象,通过分析微细电火花铣削加工特性和短路产生原因,本文提出了一种基于正方形约束的插补算法和基于动态周期的进给控制方法,并为该插补算法所产生的插补数值设计了基于位模式的存储结构。该插补算法与进给模式相结合,充分利用了微细电火花铣削加工的特性,解决了加工过程中出现的短路问题。在解决短路问题的基础上,本文进行电极补偿实验和三维结构加工的轨迹规划研究。以等量补偿和分层铣削加工理论为基础,通过工艺实验确定了电极补偿参数,并将电极补偿与三维结构轨迹规划相结合,设计出三维结构的加工轨迹,实现自动补偿加工。基于以上研究,最终开发出了微细电火花铣削加工机床控制软件,将基于正方形约束的插补算法与动态周期的进给控制方法集成于系统中,并将铣削加工过程中的加工状态、电极补偿参数、手动控制和加工参数调整等集成于系统中,同时对运动控制卡中的PID控制系统进行参数调节,满足伺服运动的灵敏性和精确度要求,实现了对机床三轴联动的精确控制。
通过实验验证,本文提出的基于正方形约束的插补算法和动态周期进给控制模式,以及本文开发的微细电火花铣削加工控制软件,能够在微细电火花铣削加工过程中避免电极与工件之间发生短路,将微细电火花铣削加工效率提高了30%。在三维微小结构加工实验中,利用本文确定的补偿参数和轨迹,实现了分层铣削加工过程中电极自动补偿,能够一次性加工完成三维微小结构。
There are more and more Mico-constructs in industry equipment. It demands more machining methods. Mico-EDM milling has great advantage and potential ability to machine Mico-constructs. Micro-EDM milling is a kind of manufacturing method of non-contact between tool and workpiece. It can machine many kinds of material and no cut force. But some weak points such as discharge energy, discharge distance and unstable discharge state make it hard to control the machining process and to get effective method. It is also difficult to meet the accuracy for the electrode corrosion. The electrode compensation is important to the accuracy. Therefore, it is necessary to solve short circuit and make accurate compensation and path plan.
This paper present a new interpolation method based on square constraint which can preclude short circuit in Mcro-EDM milling. There is also a new storage structure for the NC code. Based on the new interpolation method, this paper researched the feed method and present available period feed method. Meanwhile, a lot of machining experiments have been done to find the optimal electrical parameter. In the machining experiments, the new interpolation method combined with the new feed method can solve the short circuit problem and enhance the efficiency largely. The optimal electrical parameter can enhance the efficiency more. Based on the compensation parameter, this paper researched the3D' path plan and designs3D path with automatic compensation. Based on the researches above, this paper developed a numerical control software for Mico-EDM milling machine. The software contains control method, machining state display, compensation method, manual control and parameter adjustment. It can control movement of motors and platform to meet the accuracy through PMAC.
In the experiments, the software can connect well with hardware and the accuracy can meet the design requirement. As no short circuit in the machining process, the machining efficiency was improved by30%. Also, using this system, the micro-3D structure can be machined in one time with automatic compensation.
引文
[1]郭锐,赵万生,李论,等.基于Linux的微细电火花加工数控系统的研究[J].计算机集成制造系统,2007,13(2)：370-380.
[2]王振龙,赵万生,李文卓.电火花加工技术的发展趋势与工艺进展[J].制造技术与机床,2001,7：8-11.
[3]MasuzawaT, et al. Wire Electro-discharge Grinding Form Machining[J]. Annals of the CIRP,1985,34(1):431—434.
[4]Yu Z Y, Masuzawa T, Fjino M. Micro-EDM for Three-dimensional Cavities-Development of Uniform Wear Method[J]. Annals of the CIRP,1998,47(1):169-172.
[5]宋小中,刘正勋.电致伸缩型电火花微细加工伺服系统研究[J].电加工与模具,1995,3：7-11.
[6]王振龙,赵万生,狄士春等.微细电火花加工技术的研究进展[J].中国机械工程,2002,13(10)：894-898.
[7]李勇,王显军,郭旻,等.微细电火花加工关键技术研究[J].清华大学学报,1999,39(8)：45-48.
[8]赵万生.先进电火花加工技术[M].北京：国防工业出版社,2003.
[9]Wang W M, Rajurkar K P, Akamatsu K. Digital Gap Monitor and Adaptive Integral Control for Auto-Jumping in EDM [J], ASME J. Eng. Ind.,1995,117(2):253-258.
[10]任晓涛.微细电火花加工智能控制算法的研究与应用[D].大连：大连理工大学机械工程学院,2009.
[11]崔晶,李勇,熊英.微细电火花加工多模式脉冲电源的研究[J].电加工与磨具,2009,3：19-22.
[12]陈扣杰.电火花成型加工电极辅助设计与加工仿真系统的开发[D].浙江：浙江大学化学工程与生物工程学系,2010.
[13]曹亚光.三轴联动数控电火花成型加工机设计研究[D].扬州：扬州大学机械学院,2010.
[14]刘光壮.基于分层去除制造的电火花铣削加工技术的研究[D].哈尔滨：哈尔滨工业大学机电工程学院,1999.
[15]尹大勇.微细电火花铣削过程中的CAD/CAM技术及实验研究[D].哈尔滨：哈尔滨工业大学机电工程学院,2002.
[16]Aligiri, E., S. H. Yeo, et al. A new tool wear compensation method based on real-time estimation of material removal volume in micro-EDM [J]. Journal of Materials Processing Technology,2010,210(15):2292-2303.
[17]Yu, H.-L., J.-J. Luan, et al. A new electrode wear compensation method for improving performance in 3D micro EDM milling [J]. Journal of Micromechanics and Microengineering 2010,20(5), DOI:10.1088/0960.
[18]李建国.微细数控电火花仿铣加工电极的在线检测[J].机械科学与技术,2006,25(7)：834-836.
[19]Ferraris, E., D. Reynaerts, et al. Micro-EDM process investigation and comparison performance of A1302 and ZrO2 based ceramic composites [J]. CIRP Annals-Manufacturing Technology 2011,60(1):235-238.
[20]Jahan, M. P., Y. S. Wong, et al. A comparative experimental investigation of deep-hole micro-EDM drilling capability for cemented carbide (WC-Co) against austenitic stainless steel (SUS 304)[J]. The International Journal of Advanced Manufacturing Technology 2009,46(9-12):1145-1160.
[21]王元刚.混粉电火花加工机理及关键技术研究[D].大连：大连理工大学机械工程学院,2008.
[22]张恒.电火花成形加工智能脉冲电源的研究[D].浙江：浙江工业大学,2008.
[23]徐扬帆.微细电火花交给你窄脉宽脉冲电源的设计与实现[D].武汉：武汉理工大学,2010.
[24]Garn, R., A. Schubert, et al. Analysis of the effect of vibrations on the micro-EDM process at the workpiece surface [J]. Precision Engineerin,g 2011,35(2):364-368.
[25]袁松梅,赵万生.超声电火花复合加工的研究进展[J].航空精密制造技术,1998,34(6)：17-20.
[26]杨洋,王振龙,赵万生.微细电火花铣削CAD/CAM方法研究[J].2003,39(9)：97-105.
[27]栾纪杰.微细电火花加工装置及铣削加工技术的研究[D].大连：大连理工大学机械工程学院,2009.
[28]高升晖.微细及小孔电火花加工的关键技术研究[D].大连：大连理工大学机械工程学院,2008.
[29]吴继春,唐小琦,陈吉红.一种实时快速NURBS插补算法研究与实现[J].2001,6：1224-1227.
[30]何莹.高速加工插补算法的动力学行为分析与评价[D].武汉：华中科技大学,2005.
[31]白刚.基于DSP处理器的数控插补算法实现技术研究[D].长沙：湖南师范大学,2007.
[32]Sun, Y., Z. Jia, et al. Adaptive feedrate scheduling for NC machining along curvilinear paths with improved kinematic and geometric properties [J]. The International Journal of Advanced Manufacturing Technology,2006,36(1-2):60-68.
[33]Er, T. and G. Gui-sheng. Applicantion in High Speed Machine of the NURBS Curve Interpolation [J]. Modular Machine Tool & Automatic Manufacturing Technique, 2009,8:25-28.
[34]邵金均.实时前瞻的NURBS曲线插补算法研究与仿真[D].浙江：浙江工业大学,2009.
[35]张珲,徐宗俊,郭钢.CNC机床中的NURBS插补[J].工艺与检测,1999,3：19-21
[37]陈凯云,谢晓芹.节点矢量影响NURBS曲线的规律研究与应用[J].机械工程学报.2008,44(10)：294-299.
[38]裴景玉,胡德金,高长水等.智能模糊控制技术在微细电火花加工中的应用[J].上海交通大学学报,2001,35(12)：1830-1833.
[39]Chen-Chun, K., A. J. Shih, Fuzzy Logic Control of Microhole Electrical Discharge Machining [J]. Journal of Manufacturing Science and Engineering,2008,130, DOI: 10.1115/1.2977827.
[40]刘广民,张永斌,吉方.微细电火花加工间隙平均电压检测方法理论研究[J].机械设计与制造,2009,12：110-112.
[41]张永发.微细电火花放电状态的实时监测和辨识技术[D].大连：大连理工大学机械工程学院,2007.
[42]范劲松,安军.用三次NURBS表示圆弧与整圆的算法研究[J].计算机辅助设计与图形学学报,1997,9(5)：391-395.
[43]Tan, P. C., S. H. Yeo. Modeling of Recast Layer in Micro-Electrical Discharge Machining [J]. Journal of Manufacturing Science and Engineering 2010,132(3), DOI: 10.1115/1.4001480.
[2]王振龙,赵万生,李文卓.电火花加工技术的发展趋势与工艺进展[J].制造技术与机床,2001,7：8-11.
[3]MasuzawaT, et al. Wire Electro-discharge Grinding Form Machining[J]. Annals of the CIRP,1985,34(1):431—434.
[4]Yu Z Y, Masuzawa T, Fjino M. Micro-EDM for Three-dimensional Cavities-Development of Uniform Wear Method[J]. Annals of the CIRP,1998,47(1):169-172.
[5]宋小中,刘正勋.电致伸缩型电火花微细加工伺服系统研究[J].电加工与模具,1995,3：7-11.
[6]王振龙,赵万生,狄士春等.微细电火花加工技术的研究进展[J].中国机械工程,2002,13(10)：894-898.
[7]李勇,王显军,郭旻,等.微细电火花加工关键技术研究[J].清华大学学报,1999,39(8)：45-48.
[8]赵万生.先进电火花加工技术[M].北京：国防工业出版社,2003.
[9]Wang W M, Rajurkar K P, Akamatsu K. Digital Gap Monitor and Adaptive Integral Control for Auto-Jumping in EDM [J], ASME J. Eng. Ind.,1995,117(2):253-258.
[10]任晓涛.微细电火花加工智能控制算法的研究与应用[D].大连：大连理工大学机械工程学院,2009.
[11]崔晶,李勇,熊英.微细电火花加工多模式脉冲电源的研究[J].电加工与磨具,2009,3：19-22.
[12]陈扣杰.电火花成型加工电极辅助设计与加工仿真系统的开发[D].浙江：浙江大学化学工程与生物工程学系,2010.
[13]曹亚光.三轴联动数控电火花成型加工机设计研究[D].扬州：扬州大学机械学院,2010.
[14]刘光壮.基于分层去除制造的电火花铣削加工技术的研究[D].哈尔滨：哈尔滨工业大学机电工程学院,1999.
[15]尹大勇.微细电火花铣削过程中的CAD/CAM技术及实验研究[D].哈尔滨：哈尔滨工业大学机电工程学院,2002.
[16]Aligiri, E., S. H. Yeo, et al. A new tool wear compensation method based on real-time estimation of material removal volume in micro-EDM [J]. Journal of Materials Processing Technology,2010,210(15):2292-2303.
[17]Yu, H.-L., J.-J. Luan, et al. A new electrode wear compensation method for improving performance in 3D micro EDM milling [J]. Journal of Micromechanics and Microengineering 2010,20(5), DOI:10.1088/0960.
[18]李建国.微细数控电火花仿铣加工电极的在线检测[J].机械科学与技术,2006,25(7)：834-836.
[19]Ferraris, E., D. Reynaerts, et al. Micro-EDM process investigation and comparison performance of A1302 and ZrO2 based ceramic composites [J]. CIRP Annals-Manufacturing Technology 2011,60(1):235-238.
[20]Jahan, M. P., Y. S. Wong, et al. A comparative experimental investigation of deep-hole micro-EDM drilling capability for cemented carbide (WC-Co) against austenitic stainless steel (SUS 304)[J]. The International Journal of Advanced Manufacturing Technology 2009,46(9-12):1145-1160.
[21]王元刚.混粉电火花加工机理及关键技术研究[D].大连：大连理工大学机械工程学院,2008.
[22]张恒.电火花成形加工智能脉冲电源的研究[D].浙江：浙江工业大学,2008.
[23]徐扬帆.微细电火花交给你窄脉宽脉冲电源的设计与实现[D].武汉：武汉理工大学,2010.
[24]Garn, R., A. Schubert, et al. Analysis of the effect of vibrations on the micro-EDM process at the workpiece surface [J]. Precision Engineerin,g 2011,35(2):364-368.
[25]袁松梅,赵万生.超声电火花复合加工的研究进展[J].航空精密制造技术,1998,34(6)：17-20.
[26]杨洋,王振龙,赵万生.微细电火花铣削CAD/CAM方法研究[J].2003,39(9)：97-105.
[27]栾纪杰.微细电火花加工装置及铣削加工技术的研究[D].大连：大连理工大学机械工程学院,2009.
[28]高升晖.微细及小孔电火花加工的关键技术研究[D].大连：大连理工大学机械工程学院,2008.
[29]吴继春,唐小琦,陈吉红.一种实时快速NURBS插补算法研究与实现[J].2001,6：1224-1227.
[30]何莹.高速加工插补算法的动力学行为分析与评价[D].武汉：华中科技大学,2005.
[31]白刚.基于DSP处理器的数控插补算法实现技术研究[D].长沙：湖南师范大学,2007.
[32]Sun, Y., Z. Jia, et al. Adaptive feedrate scheduling for NC machining along curvilinear paths with improved kinematic and geometric properties [J]. The International Journal of Advanced Manufacturing Technology,2006,36(1-2):60-68.
[33]Er, T. and G. Gui-sheng. Applicantion in High Speed Machine of the NURBS Curve Interpolation [J]. Modular Machine Tool & Automatic Manufacturing Technique, 2009,8:25-28.
[34]邵金均.实时前瞻的NURBS曲线插补算法研究与仿真[D].浙江：浙江工业大学,2009.
[35]张珲,徐宗俊,郭钢.CNC机床中的NURBS插补[J].工艺与检测,1999,3：19-21
[37]陈凯云,谢晓芹.节点矢量影响NURBS曲线的规律研究与应用[J].机械工程学报.2008,44(10)：294-299.
[38]裴景玉,胡德金,高长水等.智能模糊控制技术在微细电火花加工中的应用[J].上海交通大学学报,2001,35(12)：1830-1833.
[39]Chen-Chun, K., A. J. Shih, Fuzzy Logic Control of Microhole Electrical Discharge Machining [J]. Journal of Manufacturing Science and Engineering,2008,130, DOI: 10.1115/1.2977827.
[40]刘广民,张永斌,吉方.微细电火花加工间隙平均电压检测方法理论研究[J].机械设计与制造,2009,12：110-112.
[41]张永发.微细电火花放电状态的实时监测和辨识技术[D].大连：大连理工大学机械工程学院,2007.
[42]范劲松,安军.用三次NURBS表示圆弧与整圆的算法研究[J].计算机辅助设计与图形学学报,1997,9(5)：391-395.
[43]Tan, P. C., S. H. Yeo. Modeling of Recast Layer in Micro-Electrical Discharge Machining [J]. Journal of Manufacturing Science and Engineering 2010,132(3), DOI: 10.1115/1.4001480.