考虑材料去除效应的五轴铣削变形分析

Deformation analysis of five⁃axis milling considering material removal effect

针对薄壁件五轴铣削加工过程中材料去除效应对工件几何形貌和刚度性能特征的耦合影响展开分析。基于微元法建立了五轴切削力模型,针对材料去除效应的几何形貌变化描述,基于切屑几何体产生原理,提出了一种能够考虑曲面曲率的刀具工件接触区域解析计算方法。该方法无需求交运算,只需曲面几何参数和刀具位姿即可求解接触区域,提高了接触区域的计算效率和精度。针对材料去除效应的刚度性能变化描述,基于摄动法获取时变参数,以影响接触区域的加工参数作为计算变量,通过迭代计算切削力求解材料去除形性耦合作用下的加工变形,获得了材料去除效应对工件几何形貌与刚度性能变化的耦合影响规律,提高了加工变形的预测精度。叶片加工实验结果显示,未考虑材料去除效应对工件形性耦合作用影响的变形预测模型的平均和最大偏差分别为0.016 mm和0.029 mm,而考虑耦合影响的预测模型的平均和最大偏差分别为0.011 mm和0.021 mm,平均预测精度提高了31.25%,验证了考虑材料去除形性耦合作用的变形预测模型的有效性,为薄壁件五轴铣削加工变形预测与误差补偿提供理论支撑。

The coupling influence of material removal effect on geometrical morphology and stiffness properties of thinwalled parts during five-axis milling process is analyzed.A five-axis cutting force model is established based on the dif⁃ferential element method.Aiming at the description of the geometric morphology change of material removal effect,based on the chip geometry generation principle,an analytical calculation method for the cutter-workpiece engagement region considering the curvature of the surface is proposed.To solve the engagement region,this method has no need of intersection operation,and only needs surface geometric parameters and cutter position,which improves the computational efficiency and accuracy.For the description of the property variation of stiffness properties of material re⁃moval effect,the time-varying parameters are obtained based on the perturbation method,the machining parameters affecting the engagement region are used as the calculation variables,and the machining deformation under the cou⁃pling effect of material removal is solved by iteratively calculating the cutting force,and the coupling effect law of mate⁃rial removal effect on the change of the geometrical morphology and stiffness of parts is obtained to improve the predic⁃tion accuracy of machining deformation.The experimental results of blade machining show that the average and maxi⁃mum deviation of the deformation prediction model without considering the material removal effect on the geometrical morphology and stiffness properties coupling were 0.016 mm and 0.029 mm,respectively,while the average and maximum deviation of the prediction model considering the effect on the geometrical morphology and stiffness proper⁃ties coupling were 0.011 mm and 0.021 mm,respectively.The average prediction accuracy is improved by 31.25%.The effectiveness of the deformation prediction model considering the coupling effect of influence of material removal effect on geometrical morphology and stiffness properties is verified.This model provides theoretical support for defor⁃mation prediction and error compensation in five-axis milling of thin-walled parts.