Dynamic characteristics of spindle with a built-in motor

The spindle system with a built-in motor can be used to simplify the structure of machine tools, to improve the machining flexibility of machine tools, and to perform the high speed machining. In this study, the dynamic characteristics of spindle with a built-in motor are quantitatively analyzed by intoducing the finite element model based on the Timoshenko theory and considering the mass and stiffness effects of the built-in motor's rotor. And an identification method of the elastic modulus of built-in motor's ortor is proposed by using the last square error method related to the experimental and theoretical natural frequencies. The experiment on the test model reveals the usefulness of the proposed identification method.