Research On Real-Time Compensation Technology Of Geometric And Thermal Errors For Gear Hobbing Machine

This paper concentrated on geometric (position) and thermal errors of YK3610 hobbing machine,error modeling,error measurement and error compensation method is studied. The main work of this dissertation can be summarized as follows.1) The effect of the relative movement between the hob and the workpiece on the gear machining accuracy is studied. The movement mechanism of the main components is investigated, and which are described as prismatic joint and rotary joint. Based on the combination of homogeneous coordinate transformation and the fundamental principle of robot kinematics, a general synthetic error model is presented according to the motion of the gear hobbing machine and the error influencing factors.2) Research on the measurement method of thermal error and position error, and the methods are analyzed and summarized. Thermal errors and position errors of YK3610 hobbing machine are measured according to the methods, and the measurement results are presented. Based on the results, the change rule of thermal error and position error is studied, which provides technical reference for error modeling and error compensation experiment.3) Research on the thermal deformations of YK3610 gear hobbing machine, and its effect on gear machining accuracy. Applied ANSYS, thermal deformation analysis of the workpiece spindle for YK3610 gear hobbing machine is fulfilled and the temperature field model of the workpiece spindle is established finally.4) Based on the fundmental theory of culstering analysis method, this paper studied the optimization of temperature variables for thermal error modeling. The temperature variables were cut down from 10 to 4. According to the advantage of back propagation neural networks and ant colony theory, a new bionic prediction model is presented based on the 4 selected temperature variables, and ant algorithm is used to train the weights of neural networks during thermal error modeling of YK3610 hobbing machien. The position error is divided into two parts, one part is related to the position of the worktable and the other part is related to the temperature. The model of the position error is presented finally.5) Based on SIEMENS 840D system, error compensation controller is designed using single-chip microcomputer, the hardware and software system of the controller is presented. The error compensation experiment for YK3610 hobbing machine is carried out. The results shows that the position error of Z axis is reduced from 21.6μm to 9μm and the thermal error is reduced from 13.8μm to 8.5μm after compensation, the compensation effect is good. The error of the gear processed is measured before and after compensation. The result shows that the machining error (The pitch error, cumulative pitch error, tooth profile error, tooth trace error, tooth thickness error) is reduced after compensation.