Research On Finite Element Analysis And Optimization For Key Parts Of NC Heavy Crankshaft Whirlwind Lathe

Finite element analysis and optimization are the important components of modern machine tool structural design, they can help the designers to predict static and dynamic performance of machine tool structures, which are used for getting good structural optimization scheme, improving the design quality and reducing design costs. In this paper, based on ANSYS software, research on finite element analysis and optimization for the key parts(whirlwind toolpost, spindle, center frame) of NC heavy crankshaft whirlwind lathe had been done.A simplified solid model of whirlwind toolpost was established by using UG software; the axial and radial oil film stiffness of all hydrostatic bearings were calculated; then, equivalent finite element model of whirlwind toolpost was built by ANSYS and the static and dynamic performance analysis were done, through which the structural deformation figures, the stress distribution figures, the first six natural frequencies and vibration modes as well as harmonic response were obtained. The analysis results showed that whirlwind toolpost structure met the design requirements.Topology optimization analysis was done for the whirlwind cutter, then, appropriate structural improvements for whirlwind cutter were executed. Analysis results showed that the optimized whirlwind cutter not only met the static and dynamic characteristics, but also eliminated eccentric mass and the whole mass of whirlwind cutter was decreased by 3.841%.The structural model of machine tool spindle was built and the equivalent model of spindle bearings was created, then, the finite element analysis model of spindle was set up, and then, the bending stiffness and stress, torsion rigidity and shear stress, modal and harmonic performance of spindle were studied.The machine tool spindle structural optimization parametric model was built by APDL of ANSYS software. Putting the radius and length of each spindle part as design variables, the first natural frequency as state variable, the weight and chuck end place deformation of spindle as optimization objects; then, multi-objective structural size optimization of spindle was carried out. The result showed that 8.28% of spindle mass was reduced, 10.19% of chuck end place spindle radial deformation was declined and the first natural frequency of spindle was increased by 14.16%.The simplified solid structural model of center frame was created. Then, static and modal finite element analysis of center frame were done, according to the analysis results, the structure weak positions of center frame were found out, then, some structure improvements were done for the center frame, analysis result showed that the comprehensive deformation value of left-side strut for optimized center frame was decreased by 14.763%.