Research On Monitoring Method For Machining Process Based On Double Constraints Of Vibration And Cutting Force

Intelligent monitoring of NC machine tool cutting process is one of the key technologies of intelligent equipment.It can not only give full play to the machine processing capacity according to the actual working conditions,increase productivity and reduce energy consumption,also can avoid the serious accident caused by the tool collision,timely protecting tool,workpiece spindle and etc.In the actual processing,the working conditions are complicated and changeable,and the characteristics of the Machine–Tool–Workpiece system(MTWs)are different,so the monitoring method seriously affects the processing effect.To solve this problem,a monitoring method of machining process based on the MTWs' s dynamic characteristics is presented in this paper.Firstly,the factors of affecting the cutting force adaptive control and the tool collision monitoring are analyzed.A monitoring method based on the double constraints of vibration and cutting force is presented which can give full play to the machining capacity of the MTWs,and then the test platform of process monitoring system(PMS)is set up.The influence mechanism of cutting condition on vibration is studied.A dynamic Model of milling process from the perspective of contact between the tool and the workpiece,the effects of radial depth of cut on the excitation and the dynamic stiffness of the process system are studied,and the influence mechanism is verified by cutting experiments.The results show that the radial cutting width significantly affects the vibration by changing the number of cutting teeth on the cutter(NCTC).A tool collision monitoring method based on vibration signal is studied.The accuracy and real-time of the tool collision identification with the acceleration vibration of the spindle head measurement are analyzed by building the transfer function model,then the collision monitoring algorithm based on PLC communication is presented.The reliability of the method is verified by the real-time test of the collision monitoring and the identification test under several common collision conditions.The PMS is used to build the test platform,and three test schemes are designed to verify the monitoring method.By comparing the performance with the traditional monitoring method of cutting force and the reliability test of the tool collision monitoring,the monitoring method based on the MTWs' s dynamic characteristics is verified.