An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal ...An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal between the two successive cuts is 270°. The cutting process can be adjusted from the unstable region to stable one whenever regenerative chatter occurs if the phase shift angle is kept 270° by the optimal regulation of spindle speed. The theoretical analysis and the experimental results prove that the optimal regulation of spindle speed can effectively control regenerative cutting chatter. In addition, a reliablelly optimal control system of reliable spindle speed is presented. There is no need for system identification of the machine tool, and it is easy to put this regenerative chatter control method into practice, so the method has excellent application prospect.展开更多
By turning a specifically designed conical part, complete process of metal cutting, in which the chatter occurs and expands, is recorded and analyzed. This process exposes that chatter vibration has two characters cal...By turning a specifically designed conical part, complete process of metal cutting, in which the chatter occurs and expands, is recorded and analyzed. This process exposes that chatter vibration has two characters called continuity and break. The continuity character means that vibration extent enlarges continuously while chatter frequency is almost changeless as the cutting depth extends downwards continuously. The break one is that chatter frequency moves rapidly downwards to a lower level while chatter remains after the cutting depth reach another given value. It is confirmed through an exciting test that the two chatter frequencies obtained in chatter test belong to the natural frequencies of workpiece system and cutting tool system respectively. From the viewpoints of chatter energy supplying and chatter mass effect, the. chatter should occur on one of the two final executive components in its natural frequency. On this basis, a new chatter model with two chatter active bodies is proposed. This new model can better explain the above phenomenon, and adapt to chatter monitoring and improvement of component structure well.展开更多
Considering the self-excited and forced vibrations in high-speed milling processes, a novel method for dynamic optimization of system stability is used to determine the cutting parameters and structural parameters by ...Considering the self-excited and forced vibrations in high-speed milling processes, a novel method for dynamic optimization of system stability is used to determine the cutting parameters and structural parameters by increasing the chatter free material removal rate (CF-MRR) and surface finish. The method is hased on the theory of the chatter stability and the semi-bandwidth of the resonant region. The objective function of the method is material removal rate(MRR),the constraints are chatter stability and surface finish, and the optimizing variables are cutting and structural parameters. The optimization procedure is stated. The method is applied to a milling system and CF-MRR is increased 18.86%. It is shown that the influences of the chatter stability and the resonance are simultaneously considered in the dynamic optimization of the milling system for increasing CF-MRR and the surface finish.展开更多
文摘An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal between the two successive cuts is 270°. The cutting process can be adjusted from the unstable region to stable one whenever regenerative chatter occurs if the phase shift angle is kept 270° by the optimal regulation of spindle speed. The theoretical analysis and the experimental results prove that the optimal regulation of spindle speed can effectively control regenerative cutting chatter. In addition, a reliablelly optimal control system of reliable spindle speed is presented. There is no need for system identification of the machine tool, and it is easy to put this regenerative chatter control method into practice, so the method has excellent application prospect.
基金National Natural Science Foundation of China(No, 50575232).
文摘By turning a specifically designed conical part, complete process of metal cutting, in which the chatter occurs and expands, is recorded and analyzed. This process exposes that chatter vibration has two characters called continuity and break. The continuity character means that vibration extent enlarges continuously while chatter frequency is almost changeless as the cutting depth extends downwards continuously. The break one is that chatter frequency moves rapidly downwards to a lower level while chatter remains after the cutting depth reach another given value. It is confirmed through an exciting test that the two chatter frequencies obtained in chatter test belong to the natural frequencies of workpiece system and cutting tool system respectively. From the viewpoints of chatter energy supplying and chatter mass effect, the. chatter should occur on one of the two final executive components in its natural frequency. On this basis, a new chatter model with two chatter active bodies is proposed. This new model can better explain the above phenomenon, and adapt to chatter monitoring and improvement of component structure well.
基金Supported by the National Key Basic Research Program of China("973"Project)(2009CB724401)the China Postdoctoral Science Foundation(20070420208)the Postdoctoral Innovation Foundation of Shandong Province(200702023)~~
文摘Considering the self-excited and forced vibrations in high-speed milling processes, a novel method for dynamic optimization of system stability is used to determine the cutting parameters and structural parameters by increasing the chatter free material removal rate (CF-MRR) and surface finish. The method is hased on the theory of the chatter stability and the semi-bandwidth of the resonant region. The objective function of the method is material removal rate(MRR),the constraints are chatter stability and surface finish, and the optimizing variables are cutting and structural parameters. The optimization procedure is stated. The method is applied to a milling system and CF-MRR is increased 18.86%. It is shown that the influences of the chatter stability and the resonance are simultaneously considered in the dynamic optimization of the milling system for increasing CF-MRR and the surface finish.