Structure Optimization And Research Of Ultra-heavy Duty Lathe's Boring Bar

Boring bar is an important part of Ultra-heavy CNC lathe,its performance is one of the important affection to measure the performance of machine tool.With the development of our country's heavy industry,processing equipment towards the large size,heavy load and low machining error direction,so need boring bar matching with it urgently,moreover,with the increasing depth of boring,boring bar is more prone to vibration.Therefore,Ultra-heavy boring bar's structure,anti-vibration and processing precision is an important subject of mechanical manufacturing industry.This thesis uses 'HT?500×160/250-NC' lathe's boring bar as the object of research,which is manufactured by QIQIHAR heavy CNC equipment company,in order to improve its cutting performance.This thesis using the structure of the boring bar as the research object,relying on the empirical formula of cutting force calculation,getting the simplified force model of boring bar under maximum load.According to the large deformation of boring bar,the function between the deformation and the wall thickness is found.The parametric model is built using ANSYS parametric design language and optimization is conducted in order to calculate an optical solution and provide evidence for the selection of the wall thickness.With regard to the segmented structure of the boring bar,static analysis in the threaded connection area is performed.Two schemes are proposed on the supporting-damping device and compared two schemes,a better one is chosen.In this scheme,the position of the supporting-damping device and the elastic modulus of the supporting block greatly affect the deformation of the boring bar.Optimization design is conducted in ANSYS software and the relationship curve,between the position of the supporting-damping device and the elastic modulus of the supporting block and the deformation of the boring bar,is obtained respectively.The optimized model of boring bar is built.In order to improve the anti-vibration performance of the boring bar,dynamics analysis is performed.The elastic modulus of the damping block plays a very important role in the anti?vibration performance.In this thesis,elastic modulus of the damping blocks changed and through a series of harmonic response analysis,the relationship curve between the elastic modulus and the maximum amplitude of the boring bar is obtained.Finally,the cutting stability of the boring bar is analyzed.The results suggest that the performance of the boring bar is improved greatly through the optimization and this study lays the foundation for the elastic support at the end of boring bar.