A method of measuring the frequency response function of the tool point based on the surface of feeding system

Abstract

In the existing method of predicting the frequency response function of the tool point, the effect of lathe feed system is considered in the tool point frequency response function. The junction surface affects the tool point frequency response function, and the junction surface include: bearing–lead screw, lead screw–nut, working bench-guide rail, tool holder–turning tool. The lathe machining system is divided into four substructures, and the lead screw–nut junction surface and workbench-guide rail junction surface have a significant effect in the tool point frequency response function, so we mainly considered the impact of these junctions surface. Through the junction surface stiffness and junction surface damping to obtain a small response at the junction surface. And the frequency response function of the substructure is obtained by hammering method and Timoshenko beam model. Finally, the frequency response function of the substructure end is coupled with the vibration response of the lead screw–nut and workbench-guide rail by the response coupling method, and finally we get the tool point frequency response function. The CA6140 lathe was used as the experimental object, and the frequency response function of the tool point is predicted by above method. The experimental results show that the predicted tool point frequency response function has a high degree of coincidence. The method proposed in this paper can quickly get the frequency response function of the tool point which laid a foundation for the accurate prediction of static and dynamic characteristics of machine tool.