Study Of Static Precision Characteristics Of Machine Tools’Supporting Parts And Rolling Guide

The analysis of static performance and precision is one of the important aspects for the reality of high performance and high precision of CNC machine tools. Based on the theory of finite element, the method of structural analysis is widely applied to the field of machine tools’performance and precision analysis, which provides a theoretical support for the design of performance and accuracy of machine tools. Compared with the traditional method of precision analysis based on the experimental detection, the analysis method of machine tools’ performance and precision based on the structural finite element analysis has a more intuitive analysis results and higher analysis efficiency.This subject comes from the National Science and Technology Major Project " Optimization design and specification of the CNC machine tool supporting parts"(2012ZX04010-011). Based on the projects above, with the help of Finite Element Method, this thesis studies the analysis methods of precision characteristics of machine tools’ supporting parts and the junction surface of rolling guide. This analysis method is applied to the analysis of static performance and precision of a Vertical Machine Center’s column as well as its junction surfaces. The specific contents are as follow:(1) By studying the structural analysis methods of finite element and the structural characteristics of machine tools’supporting parts and the junction surface of (linear) rolling guide, the analysis process of static performance including the analysis of structural characteristics, load and constraint, and displacement calculation of physical model is put forward and meanwhile, the analysis method(s) of performance for machine tools’supporting parts and its junction surfaces is(are) formulated.(2) By studying the precision characteristics of machine tools’supporting parts and the junction surface of (linear) rolling guide, based on the second variation principle and error evaluation method and combining with the finite element theory, the analysis method of performance calculation and evaluation of machine tools’supporting parts and the junction surface of linear rolling guide which is in accordance with the process of modeling of static precision, evaluation of static precision and calculation of precision characteristics, is established. (3) Using the analysis method described in this thesis, the analysis of static performance and precision of a VMC’s column and its junction surfaces of linear rolling guide is completed. The structure and the contact characteristics of ball linear guide is studied in the stage of structural characteristics analysis. During the stage of load and constraints analysis, the cutting load of the VMC is calculated and the equivalent constraints of the junction surfaces and initial geometric error are established respectively. In the stage of physical model analysis, the analysis of static performance of the column and its junction surfaces of (linear) rolling guide under different working conditions is implemented with the help of finite element software. In the stage of precision characteristic analysis, the multi-factored evaluation of static precision considering the main influence factors such as the loads, stroke position and the initial error etc, was carried out and finally the precision characteristics of the column under different factors is achieved.The results indicate that the load of Y axis has a main influence on the flatness error and angular deviation of X axis. Working stroke exerts a primarily impact on angular deviation of X axis and Y axis. The stiffness along Y axis and the bending resistance around X axis are the weak links of the column structure. The results proved the practical application value of the analysis method of static performance and precision for supporting parts and rolling linear guide of machine tools in this thesis.