【作者】 杨亮；

【导师】 卢泽生；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2007， 博士

【摘要】 随着科学技术的不断发展,在机械工程、微电子工程等领域,对工件的加工精度和表面质量的要求越来越高,特别是在国防工业领域,精密和超精密加工技术起着至关重要的作用,这直接关系着产品的精度,而产品的精度又影响产品的性能。利用高精密机床,加工出高精度零件是实现机械零件精密加工的主要途径,然而通过该途径实现高精度加工耗资巨大,为生产出精密与超精密加工机床需要解决许多技术难题,严重限制了他们的使用。利用现有条件,采用新型的复合加工方法,提高精密机床的加工精度,对提高我国尖端武器性能、打破国外的技术封锁、缩短我国与发达国家在精密工程领域的差距、促进国防事业的发展具有重要意义。本着少花钱多办事的原则,进行特种加工方法的研究,对于解决我国长期以来超精密设备需要进口的问题,也具有重大的经济效益和广阔的应用前景。超声波振动切削是一种新型的特种切削加工方法,是一种复合工艺,超声波振动在一定条件下能够有效地解决精密切削加工的问题,但是目前对其机理的研究大都根据各自的试验表象以及所得到的工艺效果分析而得。本文通过建立刀尖对应工件处的内嵌弹性区力学模型,利用断裂动力学原理进行切削区的力学分析,通过求解给定的初始条件、边界条件下的波动方程,给出裂尖区的动态断裂应力强度因子,得出工件在振动切削时由于加入了超声振动而引起的动态效应,提供了工件发生超前应力断裂的条件,从而引起了切削力的下降。与此同时,提出了超声波振动切削的弹塑性有限元模型,并综合考虑材料的硬化和应变率相关性的基础上,以切削塑性材料为例,分析了超声波振动车削中工件与刀具之间的相互作用,利用有限元仿真方法对超声振动切削中,对切削区的应力变化进行仿真,给出了刀尖前对应点的应力变化情况,与前面的理论计算进行对比分析。最后进行了SHPB动态冲击试验的验证,得到了令人满意的结果,也在一定程度上验证前面的理论分析的正确性。通过分析振动切削中刀具与工件的运动,建立精密振动切削塑性材料的平均切削力的关于振动参数的计算模型,并利用Matlab数值仿真软件给出振动切削中振动参数对平均切削力的影响规律。为振动切削加工中,超声波振动参数的选择提供了理论依据。将带有超声振动的切削刀具与切屑的作用面抽象成为一对带有外加超声振动的摩擦幅,对摩擦副表面形貌以及实际接触情况的进行分析,从粗糙峰粘附、粗糙峰犁沟、磨损残留微粒的犁沟等作用的角度入手,对摩擦副间的摩擦力加以分析,从能量的观点出发给出超声振动存在的条件下摩擦系数与表面粗糙度关系的计算模型。在自行研制的动摩擦系数实验台上进行了平面摩擦副的摩擦系数的测定。最后,设计建立了一套超声振动切削实验系统,进行超声振动切削与普通切削的对比试验,及振动切削中各参数对工件表面粗糙度等影响的实验研究,得到了较好的效果。更多还原

【Abstract】 With the development of science and technology, because machining accuracy and surface quality of work piece are more strictly required, precision and ultra-precision technique is very important in the field of mechanical engineering, microelectronic engineering, biology engineering, especially in national defense industry. This technique impacts the accuracy of products and the accuracy impacts performance of it. It is a major approach to product high precision part adopting high precision machine. However, this approach is consumption on financing. Many technique problems must be solved before precision and ultra-precision machine are produced, which restricts its application seriously. Using existing equipment and adopting new-type multiple machining is a new approach to improve machining accuracy of precision machine. It is significant to break foreign technique blocking, improve the performance of advanced weapons, shorten technological gap distancing developed countries, and promote the development of national defense.Ultrasonic vibration cutting is a new-type non-traditional machining, a multiple machining. It can resolve precision machining problem effectively under certain condition. But research on cutting mechanism is not mature, study some processing affects from the test representation, mostly. Embedded elastic zone model of cutting zone is established in this paper. By means of solving the wave equation under a given initial condition and boundary condition, making force analysis of cutting zone, dynamic stress intensity factor is showed. Dynamic effect caused by ultrasonic vibration provides condition for leading fracture of work piece, so cutting force falls down.At the same time, an elastic-plastic finite element model of vibration cutting is put forward. Materials harden and strain ration correlation is considered in this model. Interacting between work piece and tool is analyzed by finite element method, and cutting zone stress is simulated. Stress variation of a point corresponding to tool tip is described. At last, SHPB impact test is made to proof above theory analysis results in a finite degree.A calculation model about relationship between average cutting force and vibration parameters is established by analyzing the relative movement between tool and work piece in ultrasonic vibration cutting. Using the method of simulation, an effect rule on cutting force is provided. It offers a theory gist for selection of vibration parameters in practical vibration cutting.Contact surface between tool and chip is abstracted into a friction pairs with ultrasonic vibration, and the real contacting surface is analyzed. From the viewpoint of coarse peak adhere, furrow and debris furrow, friction force is analyzed. Under the condition of ultrasonic vibration, the calculation model for the relation between coefficient of friction and surface roughness is presented. Finally an experimental device for measuring the kinetic coefficient of friction was design and test is performed.In this paper an ultrasonic vibration cutting test system is designed. Some experiments about surface roughness of work piece and vibration cutting forces are made using this test system. Perfect results are given by comparison between test and theory.更多还原