高效铣刀后刀面摩擦应力波传播与衰减特性

Frictional stress wave propagation and attenuation characteristics on the flank face of a high-efficiency milling cutter

高效铣削加工过程中,受高频、断续切削载荷作用,铣刀与工件接触角度、姿态频繁变动,使得刀工界面相对摩擦力及其引起的应力波传播、衰减过程动态变化,导致高效铣削过程摩擦磨损、磨损寿命难以准确识别及预测。构建刀齿误差和铣削振动影响下的铣刀-工件动态接触关系模型,解算铣刀刀齿后刀面摩擦力,根据一维弦线理论,提出刀齿后刀面摩擦应力波传播距离、变化速率与衰减率的解算方法。结果表明,靠近刀尖处应力波峰值和变化速率更大,高效铣刀摩擦应力波衰减过程呈偏态指数型衰减。应力波解算方法的关联度验证结果表明,刀齿后刀面特征点能量与试验累积磨损深度的关联度大于0.8,验证了模型的准确性。

During high-efficiency milling,under the action of high-frequency and intermittent cutting loads,the contact angle and posture between the milling cutter and the workpiece change frequently,making the relative friction and stress waves generated at the tool-workpiece interface dynamically change,leading to difficulty in accurately identifying and predicting friction damage and wear life during high-efficiency milling.A dynamic contact relationship model between the milling cutter and the workpiece under the influence of cutter error and milling vibration was constructed.The frictional force on the flank face of the milling cutter tooth was solved.Based on the one-dimensional string theory,a solution method for calculating the propagation distance,change rate and attenuation rate of frictional stress wave on the flank face of the cutter tooth was proposed.The results show that the stress wave peak value and change rate are greater near the cutting edge.The attenuation process of frictional stress waves in high-efficiency milling cutters shows biased exponential attenuation.The correlation verification results of the stress wave calculation method show that the energy of the feature points on the flank face of the cutter teeth has a correlation of more than 0.8 with the experimental accumulated wear depth,verifying the accuracy of the model.