高速切削中刀具联接系统应力变形分析

【作者】 李天华；

【导师】 康德纯； 王殿龙；

【作者基本信息】 大连理工大学 ， 机械设计及理论， 2003， 硕士

【摘要】 切削技术是机械制造行业的传统基础工艺之一，自二十世纪八十年代以来，制造技术的全面进步，已把切削技术推向高速／超高速切削的新阶段。加工系统由三大部分构成，即机床、刀具联接系统和刀具切削部分。其中大功率、高速、高刚性机床已经上市，同时高性能的切削刀具材料也已研制成功，相比之下，刀具的联接系统成为整个加工系统的最薄弱环节之一。作为机床主轴与切削刀片之间的联接，刀具联接系统的作用有两方面：一是定位，二是夹紧。它在工作时，几个联接表面之间不可避免地存在一定的间隙，这就会影响加工精度，并导致微小振动，使得加工表面质量差，刀具寿命缩短，尤其是在高速旋转时更为明显。所以，刀具联接系统的性能提高对于整个加工系统来说，具有重要意义。 本文首先介绍了高速／超高速切削技术的理论体系及其发展趋势，阐述了刀具联接系统的研究现状；并从机床技术(如高速主轴部件、进给部件及其控制系统、加工测试技术等)和刀具技术(如刀具材料、涂层技术等)两个方面介绍了高速／超高速切削技术相关设备的发展、应用。 然后应用弹塑性力学理论，通过平衡方程、弹性本构方程、几何方程以及边界条件的确立，建立了高速状态下刀具联接系统理论分析模型，对离心力作用下的模型的变形做了理论分析，并计算出了高速旋转状态下刀柄的弹塑性极限转速。 最后，通过选取目前应用最为广泛的传统7／24联接系统和最具有发展前景的HSK联接系统，采用有限元方法和多项式拟合，研究了在高速状态下，离心力成为主要载荷的情况下典型刀具联接系统的应力和应变情况，并分析了由于刀柄和主轴膨胀变形的不同，而对于刀具联接系统的刚度和定位精度产生的影响。结果表明，HSK联接系统比7／24联接更适合于高速加工。在此基础上，进一步通过有限元模拟，分析了轴向预紧力的大小，公差及过盈量的变化对HSK刀具联接系统性能的影响。更多还原

【Abstract】 The high-speed cutting (HSC) is now recognized as one of the key manufacturing technologies for high productivity and throughput. The main components of machining system are the machine tool, the toolholder/spindle interface and the cutting tool. Machine tools with high rigidity and high power/high rpm spindles are available, as well as high performance cutting inserts. The weakest parts in the machining system is the toolholder/spindle interface system, whose stiffness is relatively low and thus negates the expensive efforts invested in stiffing the machine tool structure.Interface system must play two important roles simultaneously. One is precision location of the toolholder relative to the spindle. Another is clamping to provide adequate rigidity to the connection. When the spindle rotates at high speed, the spindle bore and the toolholder elastically expand due to the increase in centrifugal force, and the contact at the tapered face consequently become loosely. This will influence machining precision, lead to chatter vibration, worsen the machining surface quality, and shorten the tool life. This situation will be especially evident at high rotation speed. Therefore it’s very important to improve the performance of tool interface system.Firstly, the technical system of HSC and its development trend have been reviewed. The advantages of HSC have been presented, as well as the application and recent development of cutting tools and machine tools for HSC, and their related technology especially in the last decade.The model of tool interface system has been built up based on equilibrium equation, elastic constitutive relationship, strain-displacement relationship and boundary conditions by using the theory of elasticity and plasticity. Then the deformation due to centrifugal force of the model has been analyzed and the limiting speed of the toolholder has been calculated.At last, the standard 7/24 toolholder/spindle interface, which is the most popular interface system, and HSK system (which is the most prominent new interface system developed during the last decade) have been selected to study. Using the finite element method and polynomial fitting, the deformation and contact pressure distribution of the selected interface at high rotation speed has been precisely simulated. And the influences on the performance in terms of axial and radial stiffness, and the positioning accuracy of the tooling system have been analyzed. The results indicate that HSK tool interface is more suitable than 7/24 tapered interface for high speed machining. Finally, influence of interference and axial preload on the performance of HSK tool interface has been surveyed.更多还原