Investigation of spindle-tool assembly dynamics for optical grinding motorized spindles

Abstract

Advanced optical systems have brought forward higher requirements for aspheric processing of hard brittle materials, which put forward higher request to the dynamic performances of optical grinding spindles. Due to the integration of the spindle and the tool of optical machine systems, the dynamic behaviors of the spindle system are more complicated than that of other spindles. An integrated model dynamic model of optical grinding motorized spindles which consists of a bearing model, a thermal model and a spindle-tool dynamic model is proposed. The bearing model takes the effect of the thermal displacement into account, and the rotor dynamic model with the effects of the tool and damp is established by the finite element method (FEM). An example calculation on a grinding motorized spindle is preformed and the correlative test is carried out. In the process, the dynamic model is modified by the free excitation test. The mathematical results agree well with the experimental data, which indicates that the proposed model is able to analyse the bearing-spindle-tool assembly dynamics of optical grinding motorized spindles. Meanwhile, the influences of the thermo-mechanical coupled factor (TMCF) and the tool on the dynamic behaviors of the system are obtained. The conclusions are available to the dynamic analysis and design of various high speed and precision spindles.