Analysis And Calculation Of Rear Collet Chuck And Of Clamping Deformation Of Thin–Walled Workpiece

Thin-walled workpiece usually required high precision,due to the low stiffness,it is susceptible to clamping force to produce greater clamping deformation which affects the machining accuracy.In this paper,based on the analysis of positioning and clamping characteristics of thin-walled workpiece,to reduce clamping deformation and improve machining accuracy,the rear collet chuck(hereinafter referred to as collet chuck)is designed to clamp thin-walled workpiece in automatic lathe.The clamping force characteristics of collet chuck and the clamping deformation characteristics of thin-walled workpiece are analyzed and calculated by methods of theoretical deduction,finite element simulation and regression analysis.The specific research contents are as follows:Firstly,according to the positioning and clamping characteri stics of thin-walled workpiece,the clamping scheme is established.Based on the machining requirements of the workpiece,non-axial positioning and axial positioning collet chuck are designed.Secondly,according to the knowledge of material mechanics,the theoretical calculation formula of clamping force of a certain colllet chuck is deduced.At the same time,the clamping force of that colllet chuck is obtained by finite element software.The results of the finite element simulation are compared with the results of the theoretical calculation formula,and the relative error is less than 15%,which verifies the correctness of the finite element simulation method.Finally,the orthogonal test table is used to arrange the parameters(the taper angle and key structure size of collet chuck;the axial tension force;outer diameter,length was clamped and wall thickness of thin-walled workpiece,etc.)The clamping force of collet chuck and the clamping def ormation of thin-walled workpiece are obtained through finite element simulation.According to the finite element simulation results,the regression analysis method is used to establish the mathematical models for the clamping force of collet chuck and the clamping deformation of thin-walled workpiece,Which provides reference for the design of collet chuck and the clamping deformation prediction of thin-walled workpiece.