Research On Mass-reductin Design Of Key Parts For CNC Vertical Lathe

CNC machine tools are the basis of the equipment manufacturing industry. With the development of technology and the intensifying of international competition, comes the greater demand for the equipment manufacturing in national economy and defense. Therefore, researching and developing CNC machine tools with fine processing performance and good stability is of great importance on the survivability and the development of the country. CNC vertical lathe is mainly used for processing large-scale rotary parts, and the processing accuracy and efficiency are affected by the dynamic and static characteristics of the load-bearing structures such as columns and beams.This thesis conducts a mass-reduction R&D according to the finite element method based structural analysis, presenting a reference for the actual design of beams.First, according to the design parameters, the empirical formula and the relevant data searched, the cutting loads of the CNC vertical lathe was calculated, and then the constraints were determined and simplified. The finite element model of the various parts and the machine was built in Workbench, and the loads and constraints were appled to the model according to the results of the previous calculation. The finite element static analysis and modal analysis of the whole constucture were conducted respectively. The accuracy of the turning process was verified.The accuracy of the turning process was verified based on the stiffness of the whole structure derived from the result of the static analysis; and the structure was improved based on the value of the first six natural frequencies calculated in the modal analysis. Resonance will not occur according to the calculation.Secondly, according to the finite element analysis of the whole structure, the conclusion of a over stiffness structure was made, so lightening the crucial parts was necessary. In the overall structure of the machine, the beam bears the weight of the knife turret, transfering the cutting load. Therefore, this key location has a great influence on the machining accuracy, and mass-reduction designing of the beam to improve the processing performance of the machine will gain very significant effect. This thesis took the advantage of the compatibility among CATIA, HyperMesh and ANSYS, created the beam in the CATIA solid model, and then carried into HyperMesh, having the model meshed and the element type defined. The parameters was definited in ANSYS, and the parametric modeling was achieved after importing the HyperMesh treated model file.This approach takes not only the advantage of CATIA's easy modeling, but also the HyperMesh's meshing advantage, shortening the optimization time. Wrote the optimal command stream file in ANSYS using its own APDL language, run the program, and optimized the beam stucture, thereby achieving the mass-reduction.Thirdly, in order to understand the effect to the performance of the machine due to the mass-reduction design, the whole model was reshaped according to the optimized parameters. The static analysis and modal analysis were conducted, and it was verified that the mass-reduction design of the beam was reasonable and practical.The mass-reduction design of the beam provides a practical approach for the mass-reduction design of large complex case structures, and presents some certain practical reference value for the CNC vertical lathe design, production and application in the future.