Topology optimization-based design, development and testing of steel-reinforced epoxy granite vertical machining centre column

The structural vibrations experienced by traditional machine tools made up of cast iron (CI) or cast steel material lead to premature failure of the cutting tool and poor surface finish on the manufactured components. Steel-reinforced epoxy granite (SREG), an alternate material to CI, improves the static and dynamic characteristics of the machine tool structure. However, the addition of steel reinforcement in SREG affects the damping characteristics of epoxy granite (EG). The present work focuses on optimizing both EG and steel reinforcement of the vertical machining centre column to achieve favourable damping characteristics. Initially, parametric analysis is performed to arrive at an optimum configuration of only the EG column. Then, steel reinforcement is integrated into the EG column, and topology optimization is carried out with the objective of maximizing the stiffness and natural frequencies of the SREG column while minimizing the mass of the reinforcement. The multiple design configurations for steel reinforcement evolved from topology optimization are numerically investigated using finite element analysis. The scaled-down prototype of the finalized model was fabricated, after which the dynamic characteristics of the proposed SREG column are measured and compared with that of existing CI and SREG columns. The results revealed six-fold and three-fold improvements in dynamic stiffness along X- and Y-directions, respectively, and a 33% reduction in the mass of steel reinforcement than the existing SREG column.