机床床身结构性能分析及优化
|
摘要
数控机床向高速度、高精度、高效率的方向发展,必然要求机床具有较高的加工性能和较轻的重量。床身作为机床的关键零部件,其结构性能直接影响机床的加工性能。结构性能包括静、动态特性和热特性,其中动态特性的提高对降低床身振动具有很大意义。本文研究了某立式铣床床身的结构性能并基于模态分析进行结构优化。
为了研究床身的静态特性,在CATIA中建立床身的几何模型,利用SpaceClaim快速简化几何模型并导入ANSYS中建立有限元模型。静力分析的结果表明床身具有较高的静刚度和强度,为减轻床身重量提供依据。
为了克服床身静态设计的不足,提高床身的动态特性,在模态分析的基础上,研究了床身的动刚度薄弱环节。提出了利用元结构和筋板理论修改模型,建立五种方案。通过比较后选择具有较高固有频率和较轻重量的方案四。在此基础上研究出砂孔尺寸和筋板厚度对床身固有频率的影响。最后获得的方案六相比原方案重量减轻16.76%,第一阶固有频率增加35.32%。研究表明选择合适的元结构和筋板布局可以提高结构的固有频率并降低重量、节省材料。
为了控制床身的热变形,研究了温升对床身的影响。分析床身的热源和边界条件,建立床身温度场的有限元模型并在ANSYS中求解了床身的稳态温度场,结果表明床身的温升较小。施加静态载荷和热载荷对床身进行热-应力耦合分析,结果表明床身的耦合变形主要来自于热变形。对导轨的变形进行分析,表明导轨满足导向精度要求。结合床身的热变形特点,提出一些降低热变形、减小热误差的措施。
With the development of Numerical Control machine tools to the high-speed, high precision and high efficiency, higher machining capability and lighter weight are necessarily required. As the key component of machine tools, the bed's structure performance will directly influence the processing performance. The structure performance contains the static & dynamic characteristics and the thermal characteristics. Improving the dynamic characteristics of the bed will reduce the vibration of the bed. This thesis studies the structural performance of a vertical milling machine bed and its structural optimization based on modal analysis.
In order to research the static characteristics of the bed, the geometric model of the bed is created in CATIA and simplified efficiently in SpaceClaim. After importing the model to ANSYS, the finite element model is established for static analysis. The result of static analysis of the bed indicates that it is extremely high in the static stiffness and intensity of the bed, and foundations are provided to lighten it.
In order to overcome the disadvantages of static design of the bed, to raise its dynamic characteristics, the weakness of the structure is studied based on the modal analysis of the bed. Five schemes of improving the bed are proposed based on unit structures & rib walls theory. It finally find that scheme four's natural frequency is quite high and its weight is lightest relatively. The influences of the diameter of sand hole and the thickness of rib walls to the natural frequencies of the bed are researched on the base of previous work. Finally, the scheme six is released which is 16.76 percent lighter and the first frequency is 35.32 percent higher than the original one. It illustrates that the natural frequency can be raised, the weight can be reduced and the material can be saved by choosing the appropriate unit structures and rib walls.
In order to control the thermal deformation of the bed, it studies the impact of the temperature rise on the bed. Based on analyzing the heat source and boundary conditions of the bed, the finite element model of the bed's temperature field is constructed. After the calculation accomplished, the bed's temperature field dedicate that the temperature rise is extreme low. Through exerting the ststic & thermal load and calculating the heat-structure coupling, it is verified that the major deformation of the bed comes from the thermal deformation. It also indicates that the slide guides have a high steering precision. Combined with the thermal deformation characteristics of the bed, several measures are offered to reduce the thermal deformation and compensate the thermal error.
为了研究床身的静态特性,在CATIA中建立床身的几何模型,利用SpaceClaim快速简化几何模型并导入ANSYS中建立有限元模型。静力分析的结果表明床身具有较高的静刚度和强度,为减轻床身重量提供依据。
为了克服床身静态设计的不足,提高床身的动态特性,在模态分析的基础上,研究了床身的动刚度薄弱环节。提出了利用元结构和筋板理论修改模型,建立五种方案。通过比较后选择具有较高固有频率和较轻重量的方案四。在此基础上研究出砂孔尺寸和筋板厚度对床身固有频率的影响。最后获得的方案六相比原方案重量减轻16.76%,第一阶固有频率增加35.32%。研究表明选择合适的元结构和筋板布局可以提高结构的固有频率并降低重量、节省材料。
为了控制床身的热变形,研究了温升对床身的影响。分析床身的热源和边界条件,建立床身温度场的有限元模型并在ANSYS中求解了床身的稳态温度场,结果表明床身的温升较小。施加静态载荷和热载荷对床身进行热-应力耦合分析,结果表明床身的耦合变形主要来自于热变形。对导轨的变形进行分析,表明导轨满足导向精度要求。结合床身的热变形特点,提出一些降低热变形、减小热误差的措施。
With the development of Numerical Control machine tools to the high-speed, high precision and high efficiency, higher machining capability and lighter weight are necessarily required. As the key component of machine tools, the bed's structure performance will directly influence the processing performance. The structure performance contains the static & dynamic characteristics and the thermal characteristics. Improving the dynamic characteristics of the bed will reduce the vibration of the bed. This thesis studies the structural performance of a vertical milling machine bed and its structural optimization based on modal analysis.
In order to research the static characteristics of the bed, the geometric model of the bed is created in CATIA and simplified efficiently in SpaceClaim. After importing the model to ANSYS, the finite element model is established for static analysis. The result of static analysis of the bed indicates that it is extremely high in the static stiffness and intensity of the bed, and foundations are provided to lighten it.
In order to overcome the disadvantages of static design of the bed, to raise its dynamic characteristics, the weakness of the structure is studied based on the modal analysis of the bed. Five schemes of improving the bed are proposed based on unit structures & rib walls theory. It finally find that scheme four's natural frequency is quite high and its weight is lightest relatively. The influences of the diameter of sand hole and the thickness of rib walls to the natural frequencies of the bed are researched on the base of previous work. Finally, the scheme six is released which is 16.76 percent lighter and the first frequency is 35.32 percent higher than the original one. It illustrates that the natural frequency can be raised, the weight can be reduced and the material can be saved by choosing the appropriate unit structures and rib walls.
In order to control the thermal deformation of the bed, it studies the impact of the temperature rise on the bed. Based on analyzing the heat source and boundary conditions of the bed, the finite element model of the bed's temperature field is constructed. After the calculation accomplished, the bed's temperature field dedicate that the temperature rise is extreme low. Through exerting the ststic & thermal load and calculating the heat-structure coupling, it is verified that the major deformation of the bed comes from the thermal deformation. It also indicates that the slide guides have a high steering precision. Combined with the thermal deformation characteristics of the bed, several measures are offered to reduce the thermal deformation and compensate the thermal error.
引文
[1]刘斌,彭满华.模具多轴数控加工技术的现状与发展[J].模具制造,2010 (12): 77-81
[2]储开宇,杜必强.现代机床设计思想及其发展[J].水利电力机械,1999 (2): 18-20
[3]宋德文.如何提高机床结构的动刚度[J].安徽机电学院学报,2001, 16(3): 62.65
[4] Mahdavinejad Ramezanali. Finite element analysis of machine and workpiece instability in turning[J]. International Journal of Machine Tools and Manufacture, 2005, 45(7-8): 753.760
[5] Schmitz T.L. Predicting High-speed Machining Dynamics by Substructure Analysis[J]. Annals of the CIRP, 2000, (49): 303.308
[6] Padmanabhan K.K. Prediction of damping in machined joints[J]. International Journal of Machine Tools and Manufacture. 1992, 32(3): 305-314
[7] Zatarain M, Lejardi E, Egana F. Modular Synthesis of Machine Tools[J]. Annals of the CIRP, 1998, 47(1): 333.336
[8] Elbestawi M.A. Development of a Novel Modular and Agile Face Machining Technology[J]. Annals of the CIRP, 2002,51(1): 307-314
[9] Kim Sun-Min, Ha Jae-Hoon, Jeong Sung-Ho, et al. Effect of joint conditions on the dynamic behavior of a grinding wheel spindle[J]. International Journal of machine tools & Manufacture, 2001 (41): 1749-1761
[10] Heisel U, Feinauer A. Dynamic Influence on Workpiece Quality in High Speed Milling[J]. Annals of the CIRP, 1999, 48(1): 321-324
[11]张镭,窦广会,张珂,袁野,滕立波.CKS6125数控机床床身的有限元分析与研究[J].机床与液压,2009,37(7):171-223
[12]唐国兴,尹飞鸿. XH715型立式加工中心床身动态优化设计的研究[J].制造技术与机床,2008, (2):94.97
[13]王伟伟,翁泽宇,巫少龙.大型高效数控铣床有限元模态分析[J].机床与液压,2005, (6): 21-22
[14]王飞月.机床的动态特性分析[J].河北工业科技,2001, 18(4): 11-14
[15]张广鹏,史文浩,黄玉美,等.机床整机动态特性的预测解析建模方法[J].上海交通大学学报,2001, 35(12): 1834.1837
[16]王立华,罗建平,刘泓滨,等.铣床关键结合面动态特性研究[J].振动与冲击,2008, 27(8): 125-129
[17]卢熹,孙庆鸿,张建润,等. CK1416型数控车床床身结构动态分析[J].制造技术与机床,2003 (6): 45-47
[18]魏建中,刘强,袁松梅.机床动态特性对铣削力影响的实验研究[J].制造技术与机床,2009 (2): 23.26
[19]魏海燕,王先逵,郁鼎文,等.卧式加工中心试验模态分析[J].机床与液压,2003, (5): 73.75
[20]方英武,张广鹏,黄玉美.整机结构动力学特性边界元法解析[J].中国机械工程,2005, 16(19): 1708-1711
[21] Ramesh R, Mannan M.A, Poo A.N. Error compensation in machine tools-a review: Part I: geometric, cutting-force induced and fixture-dependent errors[J]. International Journal of Machine Tools and Manufacture, 2000, 40(9): 1235-1256
[22] Choi Jin Kyung, Lee Dai Gil. Thermal characteristics of the spindle bearing system with a gear located on the bearing span[J]. International Journal of Machine Tools and Manufacture, 1998, 38(9): 1017-1030
[23] Wu Cheng-Hsien, Kung Yu-Tai. Thermal analysis for the feed drive system of a CNC machine center[J]. International Journal of Machine Tools and Manufacture, 2003, 43(15): 1521-1528
[24] Lin Chi-Wei, Tu Jay F, Kamman Joe. An integrated thermo-mechanical-dynamic model to characterize motorized machine tool spindle during very high speed rotation[J]. International Journal of Machine tools and Manufacture, 2003, (43): 1035-1050
[25] Fraser S, Attia M.H, Osman M.O.M. Modelling, Identification and Control of Thermal Deformation of Machine Tool Structures, Part 1: Concept of Generalized Modelling[J]. Journal of Manufacturing Science and Engineering, 1998, 120(3): 623.671
[26] Hattori M, Noguchi H, Ito S, et al. Estimation of thermal-deformation in machine tools using neural network technique[J]. Journal of Materials Processing Technology, 1996, 56(1-4): 765-772
[27] Yun Won Soo, Kim Soo Kwang, Cho Dong Woo. Thermal error analysis for a CNC lathe feed drive system[J]. International Journal of Machine Tools and Manufacture, 1999, 39(7): 1087-1101
[28]刘又午,章青,王国锋,等.数控机床误差补偿技术及应用发展动态及展望[J].制造技术与机床,1998, (12): 5-6
[29]杨庆东,范丹伯格.C,范赫里克.P,等.数控机床热误差补偿建模方法[J].制造技术与机床,2000, (2): 10-13
[30]邹济林.机床热变形的控制与防止[J].机床与液压,2001, (5): 109-111
[31]赵中敏.机床热变形产生的原因及常用控制方法[J].重型机械科技,2007, (4): 49-54
[32]赵强,刘素明,张令,等.机床热变形产生机理及控制措施[J].煤矿机械,2008, 29(1): 160-161
[33]洪有为,孙蓓蓓,孙庆鸿,等.高速高精度数控车床主轴系统三维稳态温度场的数值分析[J].精密制造与自动化,2004, 160(4): 19-21
[34]王金生,姚春燕,彭伟. XK717数控铣床主轴系统的热特性分析[J].机床与液压,2005 (4): 16-17
[35]郭学祥,胡友民,夏军勇,等.基于有限元分析的机床导轨热变形研究[J].组合机床与自动化加工技术,2007, (3): 8-11
[36]张丽.四轴数控铲磨机床动、热特性研究[D].秦皇岛:燕山大学, 2010
[37] Yang Y, Mu?oa J, Altintas Y. Optimization of multiple tuned mass dampers to suppress machine tool chatter[J]. International Journal of Machine Tools & Manufacture, 2010 (50): 834.842
[38] Hull Patrick V, Canfield Stephen. Optimal synthesis of compliant mechanisms using subdivision and commercial FEA[J]. Journal of Mechanical Design, 2006, 128(2): 337-348
[39] Lam Y.C, Manickarajah D, Bertolini A. Performance characteristics of resizing algorithms for thickness optimization of plate structures[J]. Finite Elements in Analysis and Design, 2000, 34(2): 159-174
[40] Chen J.L, Ho J.S. Direct variational method for sizing design sensitivity analysis of beam and frame structures[J]. Computers & Structures, 1992, 42(4): 503.509
[41] Chen Biaosong, Liu Gang, Kang Jian, et al. Design optimization of stiffened storage tank for spacecraft[J]. Structural and Multidisciplinary Optimization, 2008, (36): 83.92
[42] Lagaros Nikolaos D, Fragiadakis Michalis, Papadrakakis Manolis. Optimum Design of Shell Structures with Stiffening Beams[J]. AIAA Journal, 2004, 42(1): 175-184
[43] Belblidia F, Afonso S.M.B, Hinton E, et al. Integrated design optimization of stiffened plate structures[J]. Engineering Computations, 1999, 16(8): 934.952
[44]罗震,陈立平,黄玉盈,等.基于RAMP密度-刚度插值格式的结构拓扑优化[J].计算力学学报,2005, 22(5): 585-591
[45]张云清,罗震,陈立平,等.基于移动渐近线方法的结构多刚度拓扑优化设计[J].航空学报,2006, 27(6): 1209-1216
[46]牟淑志,杜春江,牟福元.基于ANSYS二次开发的结构拓扑优化[J].计算机应用与软件,2010, 27(2): 228-230
[47]邵红艳.基于遗传算法的机床主轴动态特性优化设计[J].现代机械,2005 (4): 39-40
[48]徐燕申,张兴朝,牛占文,等.基于元结构和框架优选的数控机床床身结构动态设计研究[J].机械强度,2001, 23(1): 1-3
[49]张兴朝.基于有限元分析的模块化数控机床结构动态设计研究[D].天津:天津大学, 2001
[50]姚建飞,章正伟.基于元结构基本框架概念的床身结构动态设计[J].浙江交通职业技术学院学报,2005, 6(2): 35-37
[51]王云霞,郭玉杰.基于元结构的机床床身结构性能分析与优化设计[J].组合机床与自动化加工技术,2009 (10): 75-78
[52]毛海军,孙庆鸿,陈南,等.筋板布置型式对机床动态性能的影响[J].制造技术与机床,2001 (4): 8-9
[53]伍建国,陈新,孙庆鸿,等.内圆磨床床身结构的动态分析与优化设计[J].精密制造与自动化,2002 (2): 25-26
[54]耿新海.六主轴数控车床床身有限元分析与结构优化[D].沈阳:沈阳工业大学, 2009
[55]张学玲.基于广义模块化设计的机械结构静、动态特性分析及优化设计[D].天津:天津大学, 2004
[56]郭学祥.机床进给系统热态特性的数值仿真研究[D].武汉:华中科技大学, 2007
[2]储开宇,杜必强.现代机床设计思想及其发展[J].水利电力机械,1999 (2): 18-20
[3]宋德文.如何提高机床结构的动刚度[J].安徽机电学院学报,2001, 16(3): 62.65
[4] Mahdavinejad Ramezanali. Finite element analysis of machine and workpiece instability in turning[J]. International Journal of Machine Tools and Manufacture, 2005, 45(7-8): 753.760
[5] Schmitz T.L. Predicting High-speed Machining Dynamics by Substructure Analysis[J]. Annals of the CIRP, 2000, (49): 303.308
[6] Padmanabhan K.K. Prediction of damping in machined joints[J]. International Journal of Machine Tools and Manufacture. 1992, 32(3): 305-314
[7] Zatarain M, Lejardi E, Egana F. Modular Synthesis of Machine Tools[J]. Annals of the CIRP, 1998, 47(1): 333.336
[8] Elbestawi M.A. Development of a Novel Modular and Agile Face Machining Technology[J]. Annals of the CIRP, 2002,51(1): 307-314
[9] Kim Sun-Min, Ha Jae-Hoon, Jeong Sung-Ho, et al. Effect of joint conditions on the dynamic behavior of a grinding wheel spindle[J]. International Journal of machine tools & Manufacture, 2001 (41): 1749-1761
[10] Heisel U, Feinauer A. Dynamic Influence on Workpiece Quality in High Speed Milling[J]. Annals of the CIRP, 1999, 48(1): 321-324
[11]张镭,窦广会,张珂,袁野,滕立波.CKS6125数控机床床身的有限元分析与研究[J].机床与液压,2009,37(7):171-223
[12]唐国兴,尹飞鸿. XH715型立式加工中心床身动态优化设计的研究[J].制造技术与机床,2008, (2):94.97
[13]王伟伟,翁泽宇,巫少龙.大型高效数控铣床有限元模态分析[J].机床与液压,2005, (6): 21-22
[14]王飞月.机床的动态特性分析[J].河北工业科技,2001, 18(4): 11-14
[15]张广鹏,史文浩,黄玉美,等.机床整机动态特性的预测解析建模方法[J].上海交通大学学报,2001, 35(12): 1834.1837
[16]王立华,罗建平,刘泓滨,等.铣床关键结合面动态特性研究[J].振动与冲击,2008, 27(8): 125-129
[17]卢熹,孙庆鸿,张建润,等. CK1416型数控车床床身结构动态分析[J].制造技术与机床,2003 (6): 45-47
[18]魏建中,刘强,袁松梅.机床动态特性对铣削力影响的实验研究[J].制造技术与机床,2009 (2): 23.26
[19]魏海燕,王先逵,郁鼎文,等.卧式加工中心试验模态分析[J].机床与液压,2003, (5): 73.75
[20]方英武,张广鹏,黄玉美.整机结构动力学特性边界元法解析[J].中国机械工程,2005, 16(19): 1708-1711
[21] Ramesh R, Mannan M.A, Poo A.N. Error compensation in machine tools-a review: Part I: geometric, cutting-force induced and fixture-dependent errors[J]. International Journal of Machine Tools and Manufacture, 2000, 40(9): 1235-1256
[22] Choi Jin Kyung, Lee Dai Gil. Thermal characteristics of the spindle bearing system with a gear located on the bearing span[J]. International Journal of Machine Tools and Manufacture, 1998, 38(9): 1017-1030
[23] Wu Cheng-Hsien, Kung Yu-Tai. Thermal analysis for the feed drive system of a CNC machine center[J]. International Journal of Machine Tools and Manufacture, 2003, 43(15): 1521-1528
[24] Lin Chi-Wei, Tu Jay F, Kamman Joe. An integrated thermo-mechanical-dynamic model to characterize motorized machine tool spindle during very high speed rotation[J]. International Journal of Machine tools and Manufacture, 2003, (43): 1035-1050
[25] Fraser S, Attia M.H, Osman M.O.M. Modelling, Identification and Control of Thermal Deformation of Machine Tool Structures, Part 1: Concept of Generalized Modelling[J]. Journal of Manufacturing Science and Engineering, 1998, 120(3): 623.671
[26] Hattori M, Noguchi H, Ito S, et al. Estimation of thermal-deformation in machine tools using neural network technique[J]. Journal of Materials Processing Technology, 1996, 56(1-4): 765-772
[27] Yun Won Soo, Kim Soo Kwang, Cho Dong Woo. Thermal error analysis for a CNC lathe feed drive system[J]. International Journal of Machine Tools and Manufacture, 1999, 39(7): 1087-1101
[28]刘又午,章青,王国锋,等.数控机床误差补偿技术及应用发展动态及展望[J].制造技术与机床,1998, (12): 5-6
[29]杨庆东,范丹伯格.C,范赫里克.P,等.数控机床热误差补偿建模方法[J].制造技术与机床,2000, (2): 10-13
[30]邹济林.机床热变形的控制与防止[J].机床与液压,2001, (5): 109-111
[31]赵中敏.机床热变形产生的原因及常用控制方法[J].重型机械科技,2007, (4): 49-54
[32]赵强,刘素明,张令,等.机床热变形产生机理及控制措施[J].煤矿机械,2008, 29(1): 160-161
[33]洪有为,孙蓓蓓,孙庆鸿,等.高速高精度数控车床主轴系统三维稳态温度场的数值分析[J].精密制造与自动化,2004, 160(4): 19-21
[34]王金生,姚春燕,彭伟. XK717数控铣床主轴系统的热特性分析[J].机床与液压,2005 (4): 16-17
[35]郭学祥,胡友民,夏军勇,等.基于有限元分析的机床导轨热变形研究[J].组合机床与自动化加工技术,2007, (3): 8-11
[36]张丽.四轴数控铲磨机床动、热特性研究[D].秦皇岛:燕山大学, 2010
[37] Yang Y, Mu?oa J, Altintas Y. Optimization of multiple tuned mass dampers to suppress machine tool chatter[J]. International Journal of Machine Tools & Manufacture, 2010 (50): 834.842
[38] Hull Patrick V, Canfield Stephen. Optimal synthesis of compliant mechanisms using subdivision and commercial FEA[J]. Journal of Mechanical Design, 2006, 128(2): 337-348
[39] Lam Y.C, Manickarajah D, Bertolini A. Performance characteristics of resizing algorithms for thickness optimization of plate structures[J]. Finite Elements in Analysis and Design, 2000, 34(2): 159-174
[40] Chen J.L, Ho J.S. Direct variational method for sizing design sensitivity analysis of beam and frame structures[J]. Computers & Structures, 1992, 42(4): 503.509
[41] Chen Biaosong, Liu Gang, Kang Jian, et al. Design optimization of stiffened storage tank for spacecraft[J]. Structural and Multidisciplinary Optimization, 2008, (36): 83.92
[42] Lagaros Nikolaos D, Fragiadakis Michalis, Papadrakakis Manolis. Optimum Design of Shell Structures with Stiffening Beams[J]. AIAA Journal, 2004, 42(1): 175-184
[43] Belblidia F, Afonso S.M.B, Hinton E, et al. Integrated design optimization of stiffened plate structures[J]. Engineering Computations, 1999, 16(8): 934.952
[44]罗震,陈立平,黄玉盈,等.基于RAMP密度-刚度插值格式的结构拓扑优化[J].计算力学学报,2005, 22(5): 585-591
[45]张云清,罗震,陈立平,等.基于移动渐近线方法的结构多刚度拓扑优化设计[J].航空学报,2006, 27(6): 1209-1216
[46]牟淑志,杜春江,牟福元.基于ANSYS二次开发的结构拓扑优化[J].计算机应用与软件,2010, 27(2): 228-230
[47]邵红艳.基于遗传算法的机床主轴动态特性优化设计[J].现代机械,2005 (4): 39-40
[48]徐燕申,张兴朝,牛占文,等.基于元结构和框架优选的数控机床床身结构动态设计研究[J].机械强度,2001, 23(1): 1-3
[49]张兴朝.基于有限元分析的模块化数控机床结构动态设计研究[D].天津:天津大学, 2001
[50]姚建飞,章正伟.基于元结构基本框架概念的床身结构动态设计[J].浙江交通职业技术学院学报,2005, 6(2): 35-37
[51]王云霞,郭玉杰.基于元结构的机床床身结构性能分析与优化设计[J].组合机床与自动化加工技术,2009 (10): 75-78
[52]毛海军,孙庆鸿,陈南,等.筋板布置型式对机床动态性能的影响[J].制造技术与机床,2001 (4): 8-9
[53]伍建国,陈新,孙庆鸿,等.内圆磨床床身结构的动态分析与优化设计[J].精密制造与自动化,2002 (2): 25-26
[54]耿新海.六主轴数控车床床身有限元分析与结构优化[D].沈阳:沈阳工业大学, 2009
[55]张学玲.基于广义模块化设计的机械结构静、动态特性分析及优化设计[D].天津:天津大学, 2004
[56]郭学祥.机床进给系统热态特性的数值仿真研究[D].武汉:华中科技大学, 2007