A new method using double distributed joint interface model for three-dimensional dynamics prediction of spindle-holder-tool system

The cutting process stability strongly depends on dynamics of the spindle-holder-tool system, which often changes and is determined by impact hammer testing in general. In order to avoid repeated and time-consuming impact hammer testing on different spindle-holder-tool combinations, this paper proposes a new method for three-dimensional dynamics prediction of spindle-holder-tool system. The system is modeled using Timoshenko’s beam theory and substructure synthesis method. The tool-holder connection is regarded as a double distributed joint interface model including a collet, a holder-collet joint interface and a tool-collet joint interface. The two joint interfaces are further modeled as two sets of independent spring-damper elements, while the collet and tool are modeled as Timoshenko beams with varying cross-sections. The substructure synthesis method is adopted to obtain the equation of motion of the spindle-holder-tool system. Finally, experiments of bending, torsional, and axial FRFs are carried out to verify the proposed method. Good agreements show that the new method is capable of predicting tool point FRFs more accurately compared with the existing methods.