Theoretical And Experimental Research And Structural Optimization Of The Dynamic Characteristics Of Composite Machine Tool Beds

The lathe bed is the basic part of a machine tool.It provides support for workbench,tool holder and other components and suffers the cutting forces and other alternating loads at the same time.Alternating loads can cause vibration of the bed and seriously affect the machining accuracy.As the damping of cast iron is very small,cast iron bed will have a greater amplitude of vibration when it is in the working station.In recent years,people have developed resin-mineral material and it's damping is ten times of cast iron.Using resin-mineral material to manufacture the bed can reduce the amplitude of vibration and improve the machining accuracy of the machine tool.In this paper,a grinder bed made of resin-mineral material is designed on the basis of original cast iron bed.The strength checks of the guides were carried out on the basis of force analysis and finite element simulation.The dynamic characteristics of the bed were studied,including modal analysis and tests,transient dynamic analysis.The simulation results of the grinder bed are compared with the experimental results,which verified the correctness of the finite element model.The experimental results of cast iron bed were compared with resin-mineral material bed,which showed that resin-mineral material bed had better dynamic characteristics.The structure of the bed was analyzed synthetically,and the embedded parts were applied to the resin-mineral material bed.The reinforced bed was simulated to verify its validity.Then the size optimization was carried out,the sizes which contributed greatly to the dynamic characteristics of the bed were set as parameters.The ANSYS parametric design was carried out with the first natural frequency as the target and the volume of the bed as the constraint,then the final optimization plan was obtained.Finally,the final optimization plan was verified,the results showed that the first natural frequency of the bed increased by 4.7%when the volume of bed increased by 2%,and the static stiffness of the bed was also strengthened.