Research On The Thermal Characteristic And Thermal Error Modeling Technology For Spin- Dle Assembly Of CNC Machine Tool

With the development of the higher speed, high precision and flexible automation, the machining precision and reliability is required to be higher than before. During the machin-ing process, the temperature field is changing due to the factors of friction, cooling control system and environment, which will cause thermal deformation of related parts. So the rela-tive position between work piece and tool is changing and that means the thermal error of CNC.The thermal error of CNC turning centre spindle assembly is studied in this paper. My study consists of the areas stated as below:the finite element analysis of thermal error of spindle assembly; the development of spindle thermal coupling analysis; the optimal design of the spindle and the establishing of a thermal error model of spindle assembly. The main work is listed in details as follows:(1) The steady temperature field, the transient temperature field, the thermal defor-mation and the thermal stress for the spindle components of CNC machine tool are obtained through the thermal analysis in ANSYS. The temperature field and thermal error data on CNC spindle assembly is gotten by the experiment of CNC thermal error, which will tell the consistency between the finite element analysis and the experiment that carried on the spin-dle. The mathematical model of spindle temperature and thermal deformation has been es-tablished, and the error precision and reliability has been gotten by analysis the established mathematical model.(2) The coupled thermal analysis program for the spindle components of CNC ma-chine tool is obtained by the parametric design based on the APDL language. The steady-state temperature field, transient temperature field and thermal deformation has got-ten at different rotation speed of the program written above. The spindle thermal coupling analysis system is developed by VB calling ANSYS Based on the above established APDL program. The system achieved the parametric design and analysis of spindle by entering the spindle model dimension, boundary conditions and meshing size.(3) The wide using of mechanical optimization design is promoted by the develop-ment of computer technology. Workbench optimization design established the function of optimal design of the spindle, the corresponding response analysis as well as testing the rel-ativity of input and output parameters by using parameterized methods. Three candidates design points are gotten by the reasonable choices of the upper and lower limits of input parameters. And the best of the three has gotten. The thermal deformation of the spindle is reduced after structure optimization by comparing the results before and after the optimiza-tion.