Investigation of mechanics and machinability of titanium alloy thin-walled parts by CBN grinding head

A force model of machining TC4 titanium alloy thin-walled part is developed based on the actual geometry and abrasive characteristics of CBN grinding head in this paper. Then, the single factor experiment illustrates that the grinding force increases with the increase of the grinding depth and feed rate, while it decreases with the increase of the spindle speed. And the contrast experiment results show that new improved grinding head is beneficial for reducing the force compared with common grinding head. On the basis of the mechanics analysis, the chatter stability of grinding thin-walled parts is studied based on the modal tests of titanium alloy thin-walled parts and grinding head, and the stability lobe diagrams are finally drawn as well by considering the radial grinding depth. In addition, further research indicates that the surface roughness of vertical side wall surface and surface micro-hardness is determined by several key parameters including spindle speed, feed rate, and cutting depth in grinding process based on analysis of experiments. An optimal combination of these parameters is of great benefit to achieving better surface of the parts.