The Structural Design And Analysis On Static And Dynamic Characteristics Of Gantry Machining Center

With the arrival of Industry 4.0, "High-end CNC Machine Tool" is selected into Chinese Thirteen Five Planning again and acts as one of the key industry field by government. It hopes to assist Made in China 2025, and in striving to the developmental level of our country's manufacturing to be a higher level. Therefore, study and re-designe of the key parts'structure will improve the static and dynamic characteristics of machining center and the higher machining precision and processing efficiency will be obtained.This thesis derives from the National Science and Technology Major Projects "High-end CNC Machine Tool and Basic Manufacturing Equipment". The study on basic theory and trial-manufacture of prototype had been completed by Shaanxi University of Science and Technology and Ningxia Dahe Tool Machine Co., LTD. At the request of factory later, in order to further improve the static and dynamic characteristic, the authors turn vertical machining center into gantry machining center by using SolidWorks and ANSYS Workbench. This paper also receives the funding by Natural Science Basic Research Plan of Shaanxi Province. The main research working is described as follows:Firstly, the structural design of gantry machining center's key parts and assembly of the whole machine. Based on the vertical machining center, at the request of re-design by Dahe factory, the structural design of lathe bed, column, worktable, beam, cross-slider, ram and spindle are completed. Then assembly of the whole machine is done.Secondly, analysis on the static and dynamic characteristics of the key parts. By applying searmless connection function between SolidWorks and ANSYS Workbench, CAD model of the key parts are imported into Workbench, then the static and modal analysis are obtained. Compare the results from theoretical analysis with the requests by factory, the result showes that the strength, stiffness and first order natural frequency meet the requirements.Thirdly, drawing static stiffness maps of worktable. Because of the structural symmetry of worktable, so 54 points are selected equally between 1/4 parts of worktable. Total deformation of these 54 points is obtained and static stiffness is figured out. These numerical values are imported into MATLAB and mathematical procedure of fit surface is compiled, then static stiffness map of the whole worktable is drawn. Thus for holding component parts reasonably and improving machining precision, surface quality of parts to provide basis and support.Fourthly, analysis on the static and dynamic characteristics of gantry machining center. Conducting the static, modal and harmonic response analysis on the improved gantry machining center, by comparing analysis results with original vertical machining center, static and dynamic characteristics, machining precision, processing efficiency of gantry machining center have been greatly improved.Fifthly, optimization design of gantry machining center's key parts. Topology optimization is adopted for worktable and ram, which design size is less and structure is relatively simple. On the contrary, goal driven optimization based on screening is adopted for beam and column. The result of optimization showes that these two optimizations not only improve static and dynamic characteristics, but also meet the goal for lightening mass of parts, and manufacturing and transportation costs are economized.