Dynamic Characteristics Analysis And Stability Of Deep Hole Variable Stiffness/Damping Drilling Tool System

With the extensive applicationof deep hole processing technology in the aviation,weapons and metallurgical industries and other fields , the more stringent requirements of the processing accuracy, processing efficiency and reliability areproposed, especially in the deep hole machining tool dynamic vibration control problem. In the process of deep hole machining, the machining quality of the deep hole parts is poor and the processing efficiency is low because of the tool chatter, the gyroscopic effect of the cutter bar and the supporting conditions. So, how to achieve precise control of the dynamic behavior of the tool, and efficient drilling to form a predetermined quality requirement of the deep hole parts has become a deep hole drilling research hot and key issues. Therefore, the dynamic characteristics and stability of the new variable stiffness / damping drilling system are studied. It provides a reference for the analysis and resolving the vibration suppression problem of the actual deep hole drilling system, which has important theoretical significance and engineering application value.Based on the actual working characteristics of deep hole drilling and the analysis of the cutting force distribution characteristics of the tool under the actual processing, the kinetic equations of the deep hole drilling tool system is constructed combined with the Euler-Bernoulli beam theory and the balance of cutting force. On the basis of this, the matrix transfer function method is used to make more important local design information into the dynamic equation of the deep hole cutter system, such as the variable stiffness / damping auxiliary support, oil extractor and tool structure, etc, which reveals the law and characteristics of the natural frequency of the cutting tool system under different drilling depths.According to the real and imaginary part characteristic information of frequency domain characteristic vector, the stability criterion of deep hole cutting tool system is formed.Combined with a large number of numerical simulations, the relationship between the stability of the deep hole drilling tool system and the machining speed, drilling depth, and the formation mechanism of the lobes are discussed considering the gyroscopic effect.The stiffness and damping parameters of the magnetorheological damper under different excitation current are obtained by using the reverse parameter identification method. In addition,the theoretical calculation is compared with the experimental results, and the stability characteristics of the deep hole cutter system under different excitation current conditions are explored. The influence of variable stiffness / damping damper on the stability of deep hole cutter system is obtained,and the validity of the method and model proposed in this paper is confirmed.