The Finite Element Analysis And Structure Optimization On Resin Mineral Composite Grinding Machine Tool Bed

Machine tool bed, which supports headstock, tailstock and other functional components, is one of the important structure parts of machine tools. Its dynamic characteristics directly affect machining accuracy, surface roughness, processing safety, and the service life of machine tool. The basic requirements of precision machine tool bed are high stiffness and high damping capacity. But the metal materials which with high stiffness, the damping performance is relatively low. On the other hand, the metal materials with high damping performance are often unable to obtain high stiffness. The best way to increase the dynamic characteristics of ultra-precision machine tool structure is to use some new materials.In this paper, on the basis of predecessors’ research of resin mineral composites, the machine tool bed made of resin mineral composite was studied. First of all, force analysis on the bed was carried out under the typical operating condition. The cutting force and gravity of parts over the machine bed were transformed into pressure applied to the main stress surface of the bed. According to the results of stress analysis, static analysis of two beds designed with resin mineral composite and cast iron were imported into the finite element software (ANSYS Workbench) to simulate for X direction, Y direction, Z direction, total deformation nephogram and equivalent stress nephogram. The results show that the resin mineral composite bed’s total deformation is slightly larger than cast iron bed, but the large deformation parts of resin mineral composite bed is far less and the whole bed deformation less fluctuation than it. It is indicated that the static performance of the resin mineral composite bed is equivalent to the cast iron bed, satisfy the use requirement.Modal analysis was carried out on the bed using the finite element software to simulate for the first eight modal frequencies and the corresponding vibration modes of the two kinds of beds. The analysis results of two kinds of material beds were compared. The results show that the natural frequency of the resin mineral composite bed was significantly higher than that of cast iron bed. Harmonic response analysis was carried out on the bed to simulate for the amplitude frequency response curves of two kinds of material beds. The results show that the vibration amplitude of resin mineral composite bed is significantly less than cast iron bed. It is indicated that the dynamic performance of resin mineral composite bed is obviously better than that of cast iron bed, proving its superiority of application to the machine tool bed.In order to further improve the comprehensive performance of the resin mineral composite bed, the structure optimization analysis of resin mineral composite bed was operated with the bed wall thickness and rib thickness as design variables and with the maximum static deformation, the first two order natural frequency and quality as the objective function. The sensitivity of the objective function with respect to the design variables were calculated by parameter analysis and the analysis on the optimal size of wall thickness and rib thickness was carried out to get the bed structure improvement scheme. The finite element analysis was carried out on the improved bed, the results show that the comprehensive performance of the improved bed was better than the original lathe bed, but its quality is higher than original bed. Topology optimization was carried out on the improved bed to achieve the lightweight of the bed. The red areas in the results can be deleted. Further improvement of the bed can be operated according to the topology optimization results. Then using the method of multi-objective optimization analysis to improve the structure of the bed, making the quality of lathe bed reduced base on good comprehensive performance, material saving. It has considerable economic and social benefits.