基于运动学的高速高精密铣削力建模:综合模型与试验

Modeling of high speed and high precision milling forces based on kinematics:Comprehensive modeling and experimental

高速高精密铣削加工中铣削力是最重要的过程参量之一,铣削力信息的准确反馈对保证加工过程中的稳定性具有十分重要的意义。然而,影响铣削力大小的因素有很多种,目前缺乏一种考虑多种因素下的综合铣削力模型。因此,着重研究并综合考虑了刀具磨损、刀具跳动、刀具弹性变形对瞬时切削厚度的影响,同时分析了弹性变形对刀具切入与切出角的影响规律,改进了刀具瞬时切削厚度模型。基于运动学分析,将切削刃位置与预加工工件形态相互统一,建立了综合铣削力模型。为验证所提出综合模型的精确性和通用性,进行铣削实验,实验结果表明,铣削力预测值与实验值吻合较好,铣削力误差值小于1%,并通过分析刀具磨损与铣削力之间的相互变化关系,得出进给方向上的铣削力与Z向的铣削力系数对刀具磨损的影响最大。因此,切向力分量以及Z向的铣削力系数的变化特征可以较好的表征刀具磨损状况,从而提高铣削加工精度和效率。

The milling force is one of the most important process parameters in high speed and high precision milling process.Accurate feedback of milling force information is very important to ensure the stability and precision of milling process.However,there are many factors that affect the milling force,and there is currently a lack of a comprehen⁃sive milling force model that considers multiple factors.Therefore,this paper focuses on research and comprehen⁃sively considers the influence of tool wear,tool run-out,and tool elastic deformation on the instantaneous undeformed cutting thickness.Furthermore,the relationship between elastic deformation and variety of entry and exit angles for each engaged flute is analyzed,and the instantaneous cutting thickness model is improved.Based on the kinematic analysis,the position of cutting edge is unified with the shape of premachined workpiece,and a comprehensive model of high speed milling force is established.To verify the accuracy and generality of the proposed model,a series of mill⁃ing experiments under different parameters are carried out.The experimental results show that the predicted value of milling force is in good agreement with the experimental value,and the error value of milling force is less than 1%.By analyzing the relationship between tool wear per tooth and milling force,it is concluded that the milling force in the feed direction has the greatest impact on the tool wear.Therefore,the radial force component can well characterize the tool wear,so as to improve the milling accuracy and efficiency.