薄壁变壁厚零件切削加工建模及其实验研究
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摘要
推进剂贮箱是空间飞行器推进系统的重要部件,其中隔膜贮箱以其可靠性高,结构简单等优点被广泛应用在空间飞行器上。它工作时,通过增压气体挤压隔膜片使其变形翻转,将推进剂输送到管路,实现空间飞行器推进剂的供应。这种贮箱隔膜片能否有效翻转是影响贮箱性能的关键因素,其中隔膜片的厚度均匀性是保证其有效翻转的主要指标。航天八院的某型号金属膜片是由纯铝制成的薄壁半球壳零件,其厚度的均匀性是在车削精加工过程中保证。然而,传统的加工方法自动化程度低,成品率低,加工周期长,严重制约了生产效率,本文为解决该型号金属膜片精加工过程中壁厚超差的难题,提高零件的生产效率,进行了深入的研究。
首先,通过研究逆向工程中的曲面重构技术,结合零件现有的加工工艺和其自身形状特点,针对零件厚度均匀性的加工要求,提出厚度建模的概念和方法。采用超声波测厚仪进行原始厚度数据采集,规划圆周和母线方向的双有序测量点并进行测厚,利用双三次B样条曲面重构技术建立厚度参数曲面模型,完成零件的数字化建模;针对加工中母线和圆周方向进给匀速的特点,采用三次B样条等参数分割的方法,获得零件的刀位点及其相应的背吃刀量,该方法既满足精度要求,且具有较高的效率。
其次,将上述理论与方法运用于实际的研究与开发中,并通过对控制方案的比较讨论,研制了薄壁变壁厚自动车削系统,它采用工控机作为上位机、PLC作为下位机的方式进行控制;微动伺服刀架采用交流伺服电机加滚珠丝杠的结构;采用触摸屏实现了人机交互的功能,并通过VC++编制上位机软件实现数据采集、计算、通信等功能。
最后,分析了加工精度与变形的影响因素,建立了切削力、夹持力对零件在车削加工过程中的影响的力学分析模型;利用薄壁变壁厚零件自动车削系统进行了车削实验,并对加工后零件的厚度数据进行分析,基本达到预期要求,解决了精加工中壁厚超差的难题,提高了生产效率。
The tank is an important part of propulsion system in satellite. Diaphragm tank is widely used in flying organ because of its reliable and simple construction. The diapragm become deformed by air extrusion when it is working to transfer propelling agent into the pipe. So the available deformation of diapragm is the key influencing factor of the performance of tank. And homogeneous distribution of its thickness can make it deform well. In Shanghai Academy of Space Technology, some thin-walled hemisphere parts are made by aluminum and the homogeneous distribution of its thickness is vital target in its finishing machining, but the rate of finished products and the degree of automation is low, and the processing cycle is long with the previous processing technic, it badly hinder the productivity effect. The primary task in this paper is in-depth study to solve the issue of thickness out-of-tolerance and raise the productivity effect.
Firstly, after studying the surface reconstruction technology in reverse engineering and realizing the processing technic and the characteristics of the workspace shape, propose the concept and method of thickness modeling, and the ultrasonic thickness tester is used to get the original thickness data on the double sequential measuring points in circumferential and generatrix direction. The thickness model of part is reconstructed by bicubic B-spline method. Based on the characteristics of constant cutting feed movement, cutter locations are calculated by isoparametric method of B-spline in high efficiency.
Secondly, the above theories and methods are employed in industrial practice, after comparing the schemes of control system, the automatic turning device is designed which employ IPC as the host computer and PLC as the lower computer to control. The tool rest is driven by servo-actuator and ball screw. The display, supervisory system select touch screen to achieve human-computer interaction. VC++ programming is mainly used in software system to carry out functions of data acquisition, calculation and communication.
Finally, after analyzing the influence factors of machining precision and deformation, the mechanical models of deformation resulted from turning force and clamping force are established. The turning machining experiment is carried on by using the automatic turning device, it basically meet the requirement by analyzing the thickness data of the turned work piece, also solve the difficult problem of wall thickness tolerance and improve production efficiency.
首先,通过研究逆向工程中的曲面重构技术,结合零件现有的加工工艺和其自身形状特点,针对零件厚度均匀性的加工要求,提出厚度建模的概念和方法。采用超声波测厚仪进行原始厚度数据采集,规划圆周和母线方向的双有序测量点并进行测厚,利用双三次B样条曲面重构技术建立厚度参数曲面模型,完成零件的数字化建模;针对加工中母线和圆周方向进给匀速的特点,采用三次B样条等参数分割的方法,获得零件的刀位点及其相应的背吃刀量,该方法既满足精度要求,且具有较高的效率。
其次,将上述理论与方法运用于实际的研究与开发中,并通过对控制方案的比较讨论,研制了薄壁变壁厚自动车削系统,它采用工控机作为上位机、PLC作为下位机的方式进行控制;微动伺服刀架采用交流伺服电机加滚珠丝杠的结构;采用触摸屏实现了人机交互的功能,并通过VC++编制上位机软件实现数据采集、计算、通信等功能。
最后,分析了加工精度与变形的影响因素,建立了切削力、夹持力对零件在车削加工过程中的影响的力学分析模型;利用薄壁变壁厚零件自动车削系统进行了车削实验,并对加工后零件的厚度数据进行分析,基本达到预期要求,解决了精加工中壁厚超差的难题,提高了生产效率。
The tank is an important part of propulsion system in satellite. Diaphragm tank is widely used in flying organ because of its reliable and simple construction. The diapragm become deformed by air extrusion when it is working to transfer propelling agent into the pipe. So the available deformation of diapragm is the key influencing factor of the performance of tank. And homogeneous distribution of its thickness can make it deform well. In Shanghai Academy of Space Technology, some thin-walled hemisphere parts are made by aluminum and the homogeneous distribution of its thickness is vital target in its finishing machining, but the rate of finished products and the degree of automation is low, and the processing cycle is long with the previous processing technic, it badly hinder the productivity effect. The primary task in this paper is in-depth study to solve the issue of thickness out-of-tolerance and raise the productivity effect.
Firstly, after studying the surface reconstruction technology in reverse engineering and realizing the processing technic and the characteristics of the workspace shape, propose the concept and method of thickness modeling, and the ultrasonic thickness tester is used to get the original thickness data on the double sequential measuring points in circumferential and generatrix direction. The thickness model of part is reconstructed by bicubic B-spline method. Based on the characteristics of constant cutting feed movement, cutter locations are calculated by isoparametric method of B-spline in high efficiency.
Secondly, the above theories and methods are employed in industrial practice, after comparing the schemes of control system, the automatic turning device is designed which employ IPC as the host computer and PLC as the lower computer to control. The tool rest is driven by servo-actuator and ball screw. The display, supervisory system select touch screen to achieve human-computer interaction. VC++ programming is mainly used in software system to carry out functions of data acquisition, calculation and communication.
Finally, after analyzing the influence factors of machining precision and deformation, the mechanical models of deformation resulted from turning force and clamping force are established. The turning machining experiment is carried on by using the automatic turning device, it basically meet the requirement by analyzing the thickness data of the turned work piece, also solve the difficult problem of wall thickness tolerance and improve production efficiency.
引文
1 R.E.Reightler. New External Tank for Shuttle. Spaceflight. 1997,39(11):375~376
2陈志坚,王效生.钛合金气瓶、贮箱系列化的分析与研究.航天标准化. 1998年第二期:54~55
3熊焕.低温贮箱及铝锂合金的应用.导弹与航天运载技术. 2001年第6期:36~37
4 H.G. Kammerer, J. Hughes and E. Gribben. Analytical and Material Advances in Contoured Metal Diaphragms for Positive Expulsion Tanks. Atlantic Research Corporation/Liquid Propulsion. AIAA.95~2354
5常宇.贮箱隔膜变形行为的有限元分析.哈尔滨工业大学硕士学位论文. 2006
6 De Boor C. On Calculation with B-splines. Journal appox. theory. 6,1972:50~62
7 Piegl L, Tiller W. The NURBS Book(Second Edition). New York:Springer. 1997
8 Piegl L. On NURBS: A Survey. IEEE CG&A. 1991(1):55~71
9 Woodward C.D. Cross-sectional design of B-spline surfaces. Computers & Graphics. 1987,11(2):193~201
10 Woodard C.D. Skinning techniques for interactive B-spline surface interpolation. CAD. 1988,20(8):145~156
11王国瑾,王振武,寿华好. B样条曲面在严格约束条件下的光顺拟合.软件学报. 1998,9(9):696~698
12蒋大为,王自然.复杂曲面的B样条拟合方法.航空计算技术. 1996,29(2):23~26
13彭芳瑜,周济,周艳红等.基于最小二乘的曲面生成算法研究.工程图学学报. 1999,(3):41~46
14张丽艳,周来水,蔡炜斌等.基于截面测量数据的B样条曲面重建.应用科学学报. 2002,20(2):173~177
15朱心雄,张鲜. CAD/CAM中自由曲面造型技术的发展和问题.工程图学学报. 1994(2):28~36
16 Boehm W. A survey of curve and surface methods in CAGD. CAGD. 1984:1~60
17 M. Alhanaty, M. Bercovier. Curve and surface fitting and design by optimal control methods. Computer-Aided Design. 2001(33):167~182
18 M.J. Milroy, C. Bradley, G.W. Vickers, and D.J. Weir. G1 continuity of B-spline surface patches in reverse engineering. CAD. 1995(27):471~478.
19王志刚,何宁,武凯等.薄壁零件加工变形分析及控制方案[J].中国机械工程. 2002,13(2):114~117
20王增强,孟晓娴,任军学等.复杂薄壁零件数控加工变形误差控制补偿技术研究[J].机床与液压. 2006(4):61~63
21陈光军,顾立志.振动切削技术及最新发展[J].机械工程师. 2005(10):25~27
22罗跃,张明君,孔金星等.超声振动车削装置设计[J].教学与科技. 2005(2):39~43
23孔金星.低刚度薄壁零件的精密加工[J].工具技术. 2003,37(12):29~31
24郭新贵,李从心.高速切削技术的研究与应用[J].模具技术. 2001(5):61~65
25 T.J. Ko, H.S. Kim, S.S. Lee. Selection of the Machining Inclination Angle in High-Speed Ball End Milling[J]. International Journal of Advanced Manufacturing Technology. 2001,17(3):163~170
26 Schulz. H. High-speed machining[J]. Annals of the CIRP. 1992,41(2):637~643.
27 Steven Ashley. High speed Machining Goes Mainstream[J]. Mechanical Engineering. 1995(5):56~61.
28郭东明.天线罩内廓形精密测量与修磨工艺技术研究.大连理工大学博士学位论文. 2004
29 Cox M. G.. The numerical evaluation of B-spline. J.inst. maths applications. 10,1972:134~149
30施法中.计算机辅助几何设计与非均匀有理B样条.北京:高等教育出版社. 2001.
31苏步青,刘鼎元.计算几何.上海科学技术出版社. 1980
32任玉柏.数字超声波测厚仪.长春光学精密机械学院学报. 1999(4)
33杨平,廉仲.机械电子工程设计.北京:国防工业出版社. 2008.9
34江秀汉,汤楠.可编程序控制器原理及应用.西安:西安电子科技大学出版社. 2003.3. 185~186
35戴一平.可编程控制器技术及应用.北京:机械工业出版社. 2004.2
36刘思华.可编程控制器应用程序的仿真.山东大学硕士学位论文. 2005:4~6
37 Younis, Mohammed Bani. Formalization of PLC programs to sustain reliability. Automation and Mechatronics. 2004:613~618
38 K.W. Gokhay. Design of PLC control system. Electric Transmission.2001,33(7):13~15
39徐灏主.机械设计手册.北京:机械工业出版社. 2001
40李庆祥,王东生,李玉和.现代精密机械仪器设计.北京:清华大学出版社. 2004:60~104
41王运.基于DSPCPLD的运动控制器设计实现及运动控制算法研究.电子科技大学硕士学位论文. 2005:11~20
42 Kaan Erkorkmaz, Yusuf Altintas. High speed CNC system design. Part I: jerk limited trajectory generation and quintic spline interpolation[J]. International Journal of Machine Tools and Manufacture. 2001,41:1324~1335
43 (美)David J. Kruglinski著. Visual C++技术内幕.潘爱民,王国印译.北京:清华大学出版社. 2004
44 (美)Edward Angel. OpenGL编程基础.北京:清华大学出版社. 2008
45韩广利,曹文杰.机械加工工艺基础.天津:天津大学出版社. 2005
46 J.卡兹马莱科.切削、磨料及腐蚀加工原理.北京:机械工业出版社. 1985
47 Non-linear shell formulation for time-dependent deformation. Design Analysis, Robust Methods, and Stress Classification American Society of Mechanical Engineers, Pressure Vessels and Piping Division, PVP v265 1993. Pub1 by ASME, New York, NY, USA, Ont. 269~275, 1993
48徐光文.环形闭合薄壳的应力分析.工程力学97(增刊2). 674~677
49 Large viscoplastic deformations of shells. Theory and finite element formulation. Computational Mechanics v21 n6 Jun 1998:512~525
50 Theory and finite element formulation of shells at finite deformations involving thickness change: Circumventing the use of a rotation tensor. Archive of Applied Mechanics v 65 n 3 Mar 1995:194~216
51 Ratchev S, Liu S, Huang W. et al. An Advanced FEA Based Force Induced Error Compensation Strategy in Milling. International Journal of Machine Tools and Manufacture. 2006,46(5):542~551
52 James F. Cuttino, et al. Performance Optimization of a Fast Tool Servo for Single-Point Diamond Turning Machines[J]. IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL.4, N02, JUNE 1999:169~179
2陈志坚,王效生.钛合金气瓶、贮箱系列化的分析与研究.航天标准化. 1998年第二期:54~55
3熊焕.低温贮箱及铝锂合金的应用.导弹与航天运载技术. 2001年第6期:36~37
4 H.G. Kammerer, J. Hughes and E. Gribben. Analytical and Material Advances in Contoured Metal Diaphragms for Positive Expulsion Tanks. Atlantic Research Corporation/Liquid Propulsion. AIAA.95~2354
5常宇.贮箱隔膜变形行为的有限元分析.哈尔滨工业大学硕士学位论文. 2006
6 De Boor C. On Calculation with B-splines. Journal appox. theory. 6,1972:50~62
7 Piegl L, Tiller W. The NURBS Book(Second Edition). New York:Springer. 1997
8 Piegl L. On NURBS: A Survey. IEEE CG&A. 1991(1):55~71
9 Woodward C.D. Cross-sectional design of B-spline surfaces. Computers & Graphics. 1987,11(2):193~201
10 Woodard C.D. Skinning techniques for interactive B-spline surface interpolation. CAD. 1988,20(8):145~156
11王国瑾,王振武,寿华好. B样条曲面在严格约束条件下的光顺拟合.软件学报. 1998,9(9):696~698
12蒋大为,王自然.复杂曲面的B样条拟合方法.航空计算技术. 1996,29(2):23~26
13彭芳瑜,周济,周艳红等.基于最小二乘的曲面生成算法研究.工程图学学报. 1999,(3):41~46
14张丽艳,周来水,蔡炜斌等.基于截面测量数据的B样条曲面重建.应用科学学报. 2002,20(2):173~177
15朱心雄,张鲜. CAD/CAM中自由曲面造型技术的发展和问题.工程图学学报. 1994(2):28~36
16 Boehm W. A survey of curve and surface methods in CAGD. CAGD. 1984:1~60
17 M. Alhanaty, M. Bercovier. Curve and surface fitting and design by optimal control methods. Computer-Aided Design. 2001(33):167~182
18 M.J. Milroy, C. Bradley, G.W. Vickers, and D.J. Weir. G1 continuity of B-spline surface patches in reverse engineering. CAD. 1995(27):471~478.
19王志刚,何宁,武凯等.薄壁零件加工变形分析及控制方案[J].中国机械工程. 2002,13(2):114~117
20王增强,孟晓娴,任军学等.复杂薄壁零件数控加工变形误差控制补偿技术研究[J].机床与液压. 2006(4):61~63
21陈光军,顾立志.振动切削技术及最新发展[J].机械工程师. 2005(10):25~27
22罗跃,张明君,孔金星等.超声振动车削装置设计[J].教学与科技. 2005(2):39~43
23孔金星.低刚度薄壁零件的精密加工[J].工具技术. 2003,37(12):29~31
24郭新贵,李从心.高速切削技术的研究与应用[J].模具技术. 2001(5):61~65
25 T.J. Ko, H.S. Kim, S.S. Lee. Selection of the Machining Inclination Angle in High-Speed Ball End Milling[J]. International Journal of Advanced Manufacturing Technology. 2001,17(3):163~170
26 Schulz. H. High-speed machining[J]. Annals of the CIRP. 1992,41(2):637~643.
27 Steven Ashley. High speed Machining Goes Mainstream[J]. Mechanical Engineering. 1995(5):56~61.
28郭东明.天线罩内廓形精密测量与修磨工艺技术研究.大连理工大学博士学位论文. 2004
29 Cox M. G.. The numerical evaluation of B-spline. J.inst. maths applications. 10,1972:134~149
30施法中.计算机辅助几何设计与非均匀有理B样条.北京:高等教育出版社. 2001.
31苏步青,刘鼎元.计算几何.上海科学技术出版社. 1980
32任玉柏.数字超声波测厚仪.长春光学精密机械学院学报. 1999(4)
33杨平,廉仲.机械电子工程设计.北京:国防工业出版社. 2008.9
34江秀汉,汤楠.可编程序控制器原理及应用.西安:西安电子科技大学出版社. 2003.3. 185~186
35戴一平.可编程控制器技术及应用.北京:机械工业出版社. 2004.2
36刘思华.可编程控制器应用程序的仿真.山东大学硕士学位论文. 2005:4~6
37 Younis, Mohammed Bani. Formalization of PLC programs to sustain reliability. Automation and Mechatronics. 2004:613~618
38 K.W. Gokhay. Design of PLC control system. Electric Transmission.2001,33(7):13~15
39徐灏主.机械设计手册.北京:机械工业出版社. 2001
40李庆祥,王东生,李玉和.现代精密机械仪器设计.北京:清华大学出版社. 2004:60~104
41王运.基于DSPCPLD的运动控制器设计实现及运动控制算法研究.电子科技大学硕士学位论文. 2005:11~20
42 Kaan Erkorkmaz, Yusuf Altintas. High speed CNC system design. Part I: jerk limited trajectory generation and quintic spline interpolation[J]. International Journal of Machine Tools and Manufacture. 2001,41:1324~1335
43 (美)David J. Kruglinski著. Visual C++技术内幕.潘爱民,王国印译.北京:清华大学出版社. 2004
44 (美)Edward Angel. OpenGL编程基础.北京:清华大学出版社. 2008
45韩广利,曹文杰.机械加工工艺基础.天津:天津大学出版社. 2005
46 J.卡兹马莱科.切削、磨料及腐蚀加工原理.北京:机械工业出版社. 1985
47 Non-linear shell formulation for time-dependent deformation. Design Analysis, Robust Methods, and Stress Classification American Society of Mechanical Engineers, Pressure Vessels and Piping Division, PVP v265 1993. Pub1 by ASME, New York, NY, USA, Ont. 269~275, 1993
48徐光文.环形闭合薄壳的应力分析.工程力学97(增刊2). 674~677
49 Large viscoplastic deformations of shells. Theory and finite element formulation. Computational Mechanics v21 n6 Jun 1998:512~525
50 Theory and finite element formulation of shells at finite deformations involving thickness change: Circumventing the use of a rotation tensor. Archive of Applied Mechanics v 65 n 3 Mar 1995:194~216
51 Ratchev S, Liu S, Huang W. et al. An Advanced FEA Based Force Induced Error Compensation Strategy in Milling. International Journal of Machine Tools and Manufacture. 2006,46(5):542~551
52 James F. Cuttino, et al. Performance Optimization of a Fast Tool Servo for Single-Point Diamond Turning Machines[J]. IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL.4, N02, JUNE 1999:169~179