Dynamic modeling and parameters identification of a spindle-holder taper joint

Dynamic behavior of spindle-holder taper joint is critical in the spindle system of machine tool, related to the machining process. The parameters of the holder joint are significant for the spindle-holder system. This paper developed a new approach to investigate the dynamic behavior of the taper joint in modeling and parameters identification. Firstly, dynamic model is illustrated in both radial and axial directions based on the pairs of spring and damping. And frequency response function is used to identify the unknown modal parameters of frequencies and damping ratios. Secondly, a platform is designed and manufactured to establish the testing system in order to investigate the taper joint. Furthermore, taper joint of a BT50 holder is investigated, and the pre-force at the end of holder is the main consideration during the testing. The results show that the dynamic stiffness increases with the increasing of pre-force at the end of the holder. In addition, the paper discusses the phenomenon in microstructure based on peak-hollows model and the joint parameters are proved to be workable through simulation. The joint parameters are instructive to the design and manufacturing of the spindle.