Investigation on Dynamic Analysis of VMC Bed using epoxy Composite

The current trend in the machine tools market is to produce machines capable of faster cutting speeds. The level of vibration in a machine tool has always influenced the accuracy, both dimensional and geometrical, of the product machined. Increasing structural stiffness could help in avoiding these problems. Alternate materials which could increase the structural stiffness while enhancing other characteristics including damping simultaneously should be used for machine tool structures. On the other hand, epoxy composite has exceptional damping characteristics. In this work, the bed of the Vertical Machining Center was considered for modifications to enhance both its stiffness and damping characteristics. Finite element analysis (FEA) was also carried out for standard dimensions of hybrid samples of different steel face thicknesses. Static and modal analysis were carried out for the hybrid samples. From the results of the analysis the optimum thickness of the steel face for the bed is determined as 1.5 mm. The bed of Vertical Machining Center (VMC) was modeled using Pro/E and the finite element analysis of the bed was carried out. Static and modal analyses of the bed were carried out using ANSYS. The hybrid samples containing epoxy concrete core and steel face were fabricated. From the experimental results the damping factor of hybrid samples is calculated as 0.45 which is higher than the damping factor of cast iron (damping factor = 0.2)