Study On Welding Structure Design And Static And Dynamic Characteristics Of Vertical Machining Center

The machining center is a highly automated multi-function CNC machine tool with a tool magazine and automatic tool changer.Its technical level and quantity are an important symbol of a country’s manufacturing level,industrial modernization and national comprehensive competitiveness.Integral casting is often used for structural parts of CNC machine tools.However,the casting process is long and the production cost continues to increase.Especially under the new situation of environmental prevention pressure and customer tailor,overall casting is challenged,and the design and manufacture of welded structure beds are highly valued.At present,welded structure machine tools have been successfully used in forming and ordinary cutting machine tools at home and abroad.However,application of welded structures in vertical machining centers with high accuracy requirements is less,and the structures design is a simply copy of casting structures,which will cause the dense welds heavy welding stress and deformation.Based on the current status of the development of vertical machining centers,this thesis took VMC1580 vertical machining center as the research object,firstly analyzed the existing casting structure and then designed the welded structures for vertical machining center by using finite element simulation analysis.The designed welded structures have high strength and rigidity,which are not lower than that of the cast structures,and can achieve good weld-ability.The main research contents and results are as follows:(1)Using Solid Works to model the vertical column and bed of the existing VMC1580 vertical machining center,performing numerical simulation through ANSYS workbench,and analyzing the static stress/deformation characteristics and the first six modes of mode shapes for design welding Structural vertical machining centers provide an important foundation.(2)By comparison the static and dynamic characteristics analysis of the cast and the welded column and bed structures,the welded structures design are further optimized.Based on the reasonable arrangement of the internal rib structure,an innovative design of a "pipe-plate" welded structure for the vertical machining center was designed,which is beneficial to welding manufacturing and effectively resist the thin-wall flutter.The research results show that on the basis of good overall strength and stiffness,which are not lower than that of the cast structure,the quality of the welded structure column and the bed weight are reduced by 22%and 13%compared with the cast structure.(3)The static machine analysis and modal test of the prototype machine of the welded structure vertical machining center were carried out,showing that the welded structure vertical machining center has good vibration resistance,and the comparison with the simulation analysis results also verifies the correctness of the finite element model.