The Structural Strengthening And Optimization Of Resin Mineral Composite Precision Lathe Bed

Resin mineral composite, commonly known as artificial stone, is a new kind of composite material manufactured by bonding natural granite particles with organic resin. Compared to traditional material of infrastructure, resin mineral composite has many unique advantages, such as capabilities of high complex shape forming, superior damping, good thermal stability and chemical resistance, which have drawn more and more attention of designers. All the excellent features make it ideal for precision equipment manufacturing base components, such as high-speed and precision machine tools, medical equipment, and so on. This thesis mainly aims at the study of the mechanical properties and structural optimization of resin mineral composite precision lathe bed by finite element analyses.Considering both the gravity of the workpiece and other machine components and the cutting forces, load analysis of the initial designed cast iron bed shows that the mounting surface of headstock and tailstock are under the influence of uniform pressure, and the upper surfaces and the side surfaces of guide ways are under the influence of gradient loads. Measure of material properties of standard specimen manufactured with selected material formulation is also needed for the use of finite element analysis.The results of static structural analyses of precision lathe bed made of cast iron and resin mineral composite by ANSYS Workbench show that, under the same loading conditions, the deformations and stress of the bed made of resin mineral composite are less than those of cast iron bed, which means it has better static properties than the bed of cast iron. The modal analysis shows that first six natural frequencies of resin mineral composite lathe bed are improved than those of the bed made of cast iron. Conclusion can be drawn that the resin mineral composite can meet the static requirements of precision lathe bed with the current design.The result of shape optimization according to the stress distribution of the lathe bed directs the redesign of the structure inside. After redesigned, the weight of the bed decreased about 18% under the premise of ensuring the static mechanical properties, which would be a great saving of production costs. The model of the redesigned bed is conducted into SCDM to achieve the parameter arrangement of dimensions. With the goal to minimize the weight, deformation, and stress, multi-objective driven optimizations are conducted to get the sensitivity and the best combination of dimensions. Frequency responses of different direction to harmonic loads of different frequencies can be shown by the harmonic response analysis of the optimized lathe bed. The results show that, compared to the cast iron bed, the bed of resin mineral composite has a more excellent dynamic performance, which also can be regarded as guidance to avoid structural damage caused by resonance in the actual production process.In this paper, the results of static and dynamic analyses of resin mineral composite precision lathe bed and the optimal design to strengthen the bed structure lay a solid foundation for the further design and practical application in the near future.