Joint Stiffness Research On Tool System Interface

As one of the most improtant advanced manufacturing technologies,high speed machining(HSM)has a lot of advantages,compared with the traditional processing technology,including high production efficiency,small cutting force,high processing quality,low energy consumption and so on.In order to meet the environment of HSM and the demand of market,the major research institutions at home and abroad have successfully developed a series of high-quality HSM tool system.The joint performance of the spindle /toolholder interface is the most important reference part of the machine tool system,which directly affects the machining surface quality,the machining efficiency,the carrying capacity of the tool and the tool life,Therefore,scholars at home and abroad attach great importance to this aspect of the study.This paper studies the joint stiffness of the spindle / tool holder by using the means of mechanical theoretical analysis and finite element analysis.The joint stiffness includes axial stiffness,radial stiffness and torsional stiffness.The main work and results of this study are:1.Based on the contact analysis method,the axial stiffness of the interface of different tool systems is studied,the axial stiffness of the traditional tool system without end clamping positioning and the new tool system with end clamping is compared.The axial stiffness with the load changes is analyzed qualitatived,and fundamental reasons for the stiffness curve in different stages is in-depth studied.2.The mechanical stiffness model of single contact and double contact is established,and the difference in radial stiffness is analyzed.Based on the finite element analysis,the radial stiffness of different tool systems is calculated,the results show that the radial joint stiffness of the traditional BT tool system does not change with the load.Verify that the radial stiffness of the interface of the BT tool system becomes poor at high speed.3.Based on the theoretical analysis,the torque transmission form of traditional tool system and new tool system is obtained,and the calculation method of bearing torque of BT and HSK tool system is put forward.The torsional stiffness characteristics of different tool systems are studied.The reason the torque of BT40 tool system can be less than that of BBT40 and HSK40 tool system is gaved.Analyze the influence of the interference,clamping force and rotational speed on the torsional rigidity of the HSK tool system.4.The joint stiffness of different tool system interface is studied,the results show that the joint stiffness of tool system with simultaneous positioning of the cone and the end face(HSK,BBT,KM,CAPTO)is much higher than that of the traditional tool system(BT),Ensuring effective clamping of the end face is critical to ensure that the new tool system has high coupling stiffness.