基于公差约束的复杂曲面宽行加工方法
|
摘要
为了提高复杂曲面环形刀加工的加工效率,结合设计公差带,对复杂曲面的宽行加工算法进行研究。借用二阶泰勒逼近方法计算整条切削轨迹的切削带宽,根据设定的切削带宽比率阈值对其进行切削带宽可调整性评估;针对符合可调整性的切削轨迹,分析影响切削带宽的切触点,在公差约束范围内,将实际切触点沿其所在位置曲面法矢反方向平移一段合适的距离,从而反算出最优的切削带宽。通过分析切触点变化后曲面性质对切削带宽的影响,说明了公差约束思想在宽行加工算法中具有通用性。算例表明,与二阶泰勒逼近算法相比,该方法能大幅度地提高切削带宽,提高量可达到原切削带宽的26.5%,同时,切触点轨迹长度缩短了22.7%;仿真结果验证了该方法在复杂曲面环形刀宽行加工中的有效性。
To improve the efficiency of complex surfaces machining with toroidal tools,an approach about the tool path planning of strip-maximization machining is proposed by combining with the design tolerance zone.According to second-order Taylor approximation method,the strip width within the entire tool path is calculated,and then its adjustability is assessed based on the predefined strip-width-ratio threshold.For these adjustable tool path,the cutting contact points(CCPs) which decrease the strip width are analyzed.Each point of them is transformed into another actual CCP with a reasonable translation distance along the normal vector on the corresponding surface,where the value is in the constraints of tolerance zone.Thus the optimal strip-width is obtained.The influence analysis of strip-width from surface characteristic indicates that the theory based on the tolerance constraints is versatile.Example shows that the strip-width calculated by the proposed method is significantly expanded by 26.5%,comparing to second-order Taylor approximation method.Meanwhile,the length of the CCPs path is shortened by 22.7%.Therefore,the simulation result verifies the effectiveness in the complex surface machining with toroidal cutters.
To improve the efficiency of complex surfaces machining with toroidal tools,an approach about the tool path planning of strip-maximization machining is proposed by combining with the design tolerance zone.According to second-order Taylor approximation method,the strip width within the entire tool path is calculated,and then its adjustability is assessed based on the predefined strip-width-ratio threshold.For these adjustable tool path,the cutting contact points(CCPs) which decrease the strip width are analyzed.Each point of them is transformed into another actual CCP with a reasonable translation distance along the normal vector on the corresponding surface,where the value is in the constraints of tolerance zone.Thus the optimal strip-width is obtained.The influence analysis of strip-width from surface characteristic indicates that the theory based on the tolerance constraints is versatile.Example shows that the strip-width calculated by the proposed method is significantly expanded by 26.5%,comparing to second-order Taylor approximation method.Meanwhile,the length of the CCPs path is shortened by 22.7%.Therefore,the simulation result verifies the effectiveness in the complex surface machining with toroidal cutters.
引文
[1]JUN C S,CHA K,LEE Y S.Optimizing tool orientationfor 5-axis machining by configuration-space searchmethod[J].Computer-Aided Design,2003,35(5):549-566.
[2]吴宝海,罗明,张莹,等.复杂曲面五轴加工刀具轨迹规划技术的研究进展[J].机械工程学报,2008,44(10):9-18.WU Baohai,LUO Ming,ZHANG Ying,et al.Advancesin tool path planning techniques for 5-axis machining ofsculptured surfaces[J].Chinese Journal of MechanicalEngineering,2008,44(10):9-18.
[3]陈涛,钟毅芳,周济.自由曲面5轴数控加工刀位轨迹的生成算法[J].机械工程学报,2001,37(12):100-103.CHEN Tao,ZHONG Yifang,ZHOU Ji.Algorithm ofcutter location path generation for five-axis NCmachining of sculptured surfaces[J].Chinese Journal ofMechanical Engeering,2001,37(12):100-103.
[4]MADHAVULU G,SENDER S A,AHMED B.CAD/CAM solutions for efficient machining of turbomachinery components by Sturz milling method[C]//Proceedings of the 1996 IEEE IECON 22nd InternationalConference.1996:1490-1495.
[5]WARKENT IN A,BEDI S,ISMAIL F.Five-axis millingof spherical surfaces[J].International Journal of MachineTools and Manufacture,1996,36(2):229-243.
[6]倪炎榕,马登哲,张洪,等.圆环面刀具五坐标数控加工复杂曲面优化刀位算法[J].机械工程学报,2001,37(2):87-91.NI Yanrong,MA Dengzhe,ZHANG Hong,et al.Optimalorientation control for torus tool 5-axis sculptured surfaceNC machining[J].Chinese Journal of MechanicalEngeering,2001,37(2):87-91.
[7]吕雪丽,张洪.广域曲率吻合原则与复杂曲面数控加工的全面优化[J].机械设计与制造,2003(5):94-96.LüXueli,ZHANG Hong.Principle of global curvaturefitting and global optimization of sculptured surface NCmachining[J].Machinery Design&Manufacture,2003(5):94-96.
[8]李志兵,陈志同,王爽,等.基于环面刀具的叶片过渡区域宽行加工技术[J].航空学报,2011,32(9):1722-1731.LI Zhibing,CHEN Zhitong,WANG Shuang,et al.5-axismachining technology of turbine blade’s root area instripe-width maximization method with torus cutter[J].Acta Aeronautica et Astronautica Sinica,2011,32(9):1722-1731.
[9]YOON J H,POTTMANN H,LEE Y S.Locally optimalcutting positions for 5-axis sculptured surfacemachining[J].Computer-Aided Design,2003,35(1):69-81.
[10]张莹,张定华,吴宝海,等.复杂曲面环形刀五轴加工的自适应刀轴矢量优化方法[J].机械工程学报,2008,19(8):945-948.ZHANG Ying,ZHANG Dinghua,WU Baohai,et al.Anadaptive optimizing tool orientation method for 5-axistoroidal-end milling of free-form surfaces[J].ChineseJournal of Mechanical Engineering,2008,19(8):945-948.
[11]CHIOU J C J,LEE Y S.Optimal tool orientation forfive-axis tool-end machining by swept envelopeapproach[J].Transactions of the ASME,Journal ofManufacturing Science and Engineering,2005,127(4):810-818.
[12]金曼,张俐,陈志同.圆环面刀具五坐标加工端点误差控制刀位优化[J].北京航空航天大学学报,2006,32(9):1125-1128.JIN Man,ZHANG Li,CHEN Zhitong.End-points errorcontrolling method for torus tool position optimization infive-axis NC machining[J].Journal of Beijing Universityof Aeronautics and Astronautics,2006,32(9):1125-1128.
[13]FAN J,BALl A.Quadric method for cutter orientation infive-axis sculptured surface machining[J].InternationalJournal of Machine Tools&Manufacture,2008,48(7-8):788-801.
[14]吴宝海,张莹,张定华.基于广域空间的复杂曲面宽行加工方法[J].机械工程学报,2011,47(15):181-187.WU Baihai,ZHANG Ying,ZHANG Dinghua.Anapproach to strip-maximization machining based onglobal space for free-form surfaces[J].Journal ofMechanical Engeering,2011,47(15):181-187.
[15]陈志同,乐毅,徐汝锋.中点误差控制宽行加工算法[J].机械工程学报,2011,47(1):117-123.CHEN Zhitong,LE Yi,XU Nufeng.A Middle-point-error-control method in strip-width maximization-machining[J].Journal of Mechanical Engineering,2011,47(1):117-123.
[2]吴宝海,罗明,张莹,等.复杂曲面五轴加工刀具轨迹规划技术的研究进展[J].机械工程学报,2008,44(10):9-18.WU Baohai,LUO Ming,ZHANG Ying,et al.Advancesin tool path planning techniques for 5-axis machining ofsculptured surfaces[J].Chinese Journal of MechanicalEngineering,2008,44(10):9-18.
[3]陈涛,钟毅芳,周济.自由曲面5轴数控加工刀位轨迹的生成算法[J].机械工程学报,2001,37(12):100-103.CHEN Tao,ZHONG Yifang,ZHOU Ji.Algorithm ofcutter location path generation for five-axis NCmachining of sculptured surfaces[J].Chinese Journal ofMechanical Engeering,2001,37(12):100-103.
[4]MADHAVULU G,SENDER S A,AHMED B.CAD/CAM solutions for efficient machining of turbomachinery components by Sturz milling method[C]//Proceedings of the 1996 IEEE IECON 22nd InternationalConference.1996:1490-1495.
[5]WARKENT IN A,BEDI S,ISMAIL F.Five-axis millingof spherical surfaces[J].International Journal of MachineTools and Manufacture,1996,36(2):229-243.
[6]倪炎榕,马登哲,张洪,等.圆环面刀具五坐标数控加工复杂曲面优化刀位算法[J].机械工程学报,2001,37(2):87-91.NI Yanrong,MA Dengzhe,ZHANG Hong,et al.Optimalorientation control for torus tool 5-axis sculptured surfaceNC machining[J].Chinese Journal of MechanicalEngeering,2001,37(2):87-91.
[7]吕雪丽,张洪.广域曲率吻合原则与复杂曲面数控加工的全面优化[J].机械设计与制造,2003(5):94-96.LüXueli,ZHANG Hong.Principle of global curvaturefitting and global optimization of sculptured surface NCmachining[J].Machinery Design&Manufacture,2003(5):94-96.
[8]李志兵,陈志同,王爽,等.基于环面刀具的叶片过渡区域宽行加工技术[J].航空学报,2011,32(9):1722-1731.LI Zhibing,CHEN Zhitong,WANG Shuang,et al.5-axismachining technology of turbine blade’s root area instripe-width maximization method with torus cutter[J].Acta Aeronautica et Astronautica Sinica,2011,32(9):1722-1731.
[9]YOON J H,POTTMANN H,LEE Y S.Locally optimalcutting positions for 5-axis sculptured surfacemachining[J].Computer-Aided Design,2003,35(1):69-81.
[10]张莹,张定华,吴宝海,等.复杂曲面环形刀五轴加工的自适应刀轴矢量优化方法[J].机械工程学报,2008,19(8):945-948.ZHANG Ying,ZHANG Dinghua,WU Baohai,et al.Anadaptive optimizing tool orientation method for 5-axistoroidal-end milling of free-form surfaces[J].ChineseJournal of Mechanical Engineering,2008,19(8):945-948.
[11]CHIOU J C J,LEE Y S.Optimal tool orientation forfive-axis tool-end machining by swept envelopeapproach[J].Transactions of the ASME,Journal ofManufacturing Science and Engineering,2005,127(4):810-818.
[12]金曼,张俐,陈志同.圆环面刀具五坐标加工端点误差控制刀位优化[J].北京航空航天大学学报,2006,32(9):1125-1128.JIN Man,ZHANG Li,CHEN Zhitong.End-points errorcontrolling method for torus tool position optimization infive-axis NC machining[J].Journal of Beijing Universityof Aeronautics and Astronautics,2006,32(9):1125-1128.
[13]FAN J,BALl A.Quadric method for cutter orientation infive-axis sculptured surface machining[J].InternationalJournal of Machine Tools&Manufacture,2008,48(7-8):788-801.
[14]吴宝海,张莹,张定华.基于广域空间的复杂曲面宽行加工方法[J].机械工程学报,2011,47(15):181-187.WU Baihai,ZHANG Ying,ZHANG Dinghua.Anapproach to strip-maximization machining based onglobal space for free-form surfaces[J].Journal ofMechanical Engeering,2011,47(15):181-187.
[15]陈志同,乐毅,徐汝锋.中点误差控制宽行加工算法[J].机械工程学报,2011,47(1):117-123.CHEN Zhitong,LE Yi,XU Nufeng.A Middle-point-error-control method in strip-width maximization-machining[J].Journal of Mechanical Engineering,2011,47(1):117-123.