考虑刀具尺寸效应和刀具跳动的球头铣刀五轴微细铣削力预测

Five-axis Micro-milling Force Prediction of Ball End Milling Cutter Considering Tool Size Effect and Tool Runout

五轴微细铣削技术广泛应用于微小型零件的精密加工过程。铣削力作为加工过程中最重要的参数之一,直接影响零件的加工精度、刀具磨损和加工过程中的振动等。在球头铣刀五轴微细铣削过程中,刀—工接触几何CWE(Cutter Workpiece Engagement)及未变形切屑厚度瞬态变化,使其求解过程变得复杂和困难。综合考虑不同前倾、侧倾角度下的刀—工接触几何,推导出考虑最小切屑厚度、刀具跳动和工件材料弹性恢复的未变形切屑厚度数学表达式,建立了五轴微细铣削力的预测模型,获得铣削力的仿真结果。进行五轴微细铣削实验获得实测铣削力,并与预测铣削力进行比较,结果表明,铣削力预测值与实测值误差均在20%以内,验证了铣削力预测模型的有效性。

Five-axis micro-milling technology is widely used in the precision machining process of micro-small parts.As one of the most important parameters in the machining process,milling force directly affects the machining accuracy of the part,tool wear,vibration during machining,etc.In the five-axis fine milling process of the ball end milling cutter,the tool-workpiece contact geometry CWE and the thickness of the undeformed chips are transient,making the solution process complex and difficult.In this paper,the tool-workpiece contact geometry under different forward and roll angles is comprehensively considered,the mathematical expression of undeformed chip thickness considering the minimum chip thickness,tool runout and workpiece material elastic recovery are derived,and a five-axis micro-milling force prediction model is established,and the simulation results of the milling force are obtained.Finally,a five-axis micro-milling experiment is carried out to obtain the measured milling force.By comparing the predicted milling force with the measured milling force,it shows that the error between the predicted value of the milling force and the measured value is within 20%,which verifies the effectiveness of the proposed model.