切削系统刀尖点动力学行为分异特征研究

Research on Dynamic Behavior Variation Characteristics of Tool Tip Point of Cutting System

作为切削系统工作特性的输出端,刀尖点动力学行为具有强非线性及分异特征,直接影响着零件加工质量与生产效率。现阶段,基于理论或实验方法的刀尖点动力学特性研究存在建模复杂或测试成本过高等局限性。为此,以基于逆稳定性求解的半理论方法为理论基础,充分考虑切削系统中刀尖点及工件的双柔性,提出一种刀尖点动力学行为分异特征辨识方法。该方法将刀尖点在不同运行状态下动力学行为分异特征的辨识转化为一类优化设计问题,即以不同运行条件下刀尖点动力学参数为变量,以理论预测与实验标定所得极限切深及颤振频率的综合偏差最小为目标构建优化模型并求解,从而揭示刀尖点动力学行为的分异特征及演化规律。通过实施变切深铣削实验,对所得结果进行验证。对比分析表明,所提方法能较准确地获取刀尖点动力学行为的分异特征,有利于实现运行状态下切削稳定性的精准预测。

As the output of the working characteristics of the cutting system,the dynamic behavior of the tool tip point shows strong nonlinearity and differentiation characteristics,which directly affect the machining quality and production efficiency of workpieces.At this stage,the research on the dynamic characteristics of tool tip points based on theoretical or experimental methods has limitations such as complex modeling or high testing costs.To this end,based on the theoretical basis of the semi-theoretical method of solving the inverse stability,and fully considering the double flexibility of the tool tip point and the workpiece in the cutting system,a method for distinguishing the dynamic behavior of the tool tip point is proposed.This method transforms the identification of the differential characteristics of the dynamic behavior of the tool tip under different operating conditions into a kind of optimization design problem,that is,the dynamic parameters of the tool tip under different operating conditions are used as variables.An optimization model was established to minimize the comprehensive deviation of the ultimate cutting depth and chatter frequency obtained from theoretical prediction and experimental calibration,so as to reveal the differentiation characteristics and evolution law of the dynamic behavior of the tool tip.Through the implementation of variable cutting depth milling experiments,the results obtained are verified.The comparative analysis shows that the proposed method can obtain the differentiation characteristics of the dynamic behavior of the tool tip point more accurately,which is conducive to the accurate prediction of the cutting stability under the operation state.