Study On Chatter Control Of BTA Drilling

The deep hole processing is the most difficult machining procedure under the condition of the closed. Because the drill pipe is thin and long,and the rigidity is poor, it is easy to have the flutter phenomenon during drilling, so the deep hole processing has been a difficult problem in the machining process. When the chatter occurs, it will aggravate the wear of the drill bit, and affect the machining accuracy and surface quality of the hole. When the flutter is serious, it will cause the drill pipe to bend and break or even damage the machine. With the development of precision machining, people have more and more requirements for the quality of the products. Therefore, the control of chatter is generally concerned. In this paper, according to the characteristics of the BTA drilling process, a kind of electrorheological fluid damper based on fuzzy control was designed which has a certain academic value and practical significance.In this paper, the BTA deep hole drilling system as the main research object, the metal cutting process of the regenerative chatter was analyzed. The dynamic model of BTA drilling system was constructed, and the limited cutting width of the system was obtained through the theoretical analysis of regenerative chatter. The mathematical model of deep hole machining system was simulated through Matlab/Sinmulink, and the time response characteristics of tool vibration under different rotating speed and cutting width were given.Based on the current effect of ER fluid, a new type of fluid damper based on mixed mode was designed. The operating characteristic of the vibration damper was analyzed, and the dynamic model of the BTA drilling chatter control system was constructed. The mathematical model was simulated by Matlab/Sinmulink, and the response characteristics of tool vibration in time domain and frequency domain were given under different electric field strength. According to the characteristics of the damper, a fuzzy control strategy was put forward, and a fuzzy controller was designed, and the feasibility of this method was simulated and verified.The results show that when the cutting width is less than the limited cutting width at a certain speed, the machining system will not be chatter. But the size of the limited cutting width is influenced by the speed of spindle, and the change of the limited cutting width has a certain periodicity. The flutter can be avoided by adjusting the speed of spindle and cutting width. Under the action of electric field, the mixed mode current variable fluid vibration damper can obviously reduce the amplitude of the chatter of the machine tool, and effectively suppress the occurrence of the chatter. But under different electric field, the effect of the vibration damper is different. The fuzzy control has better control effect under the excitation of sinusoidal signal, random signal and machine tool chatter signal. Therefore, the current variable fluid damper based on fuzzy control can effectively control the occurrence of chatter in BTA drilling process.