平底立铣刀的切削力尺寸效应研究及其系数估算

Research on Size Effect of Cutting-force for Flat End Mills and Estimation of Its Coefficient

检验基于三元切削力机理模型的平底立铣刀尺寸效应,并探索一种简便的切削力系数估算方法。论证了在切削厚度较小时可忽略刀具螺旋角对切削力的影响,据此构建平底立铣刀单个刀齿的三元切削力简化模型。基于该模型,用各齿径向跳动量补偿瞬时切削厚度,用切削试验数据拟合各齿切削力峰值与切削深度及瞬时切削厚度的线性方程式,发现各拟合式的确定系数总体上接近1,表明同一刀齿的切削力系数大体为常数,这意味着平底立铣刀的尺寸效应不显著。据此采用刀具的平均切削力峰值估算切削力系数,该方法不用考虑刀具偏心,且计算比较简便,模拟得到的切削力波形与实测波形相近,表明估算方法比较有效。研究结果可供铣削力尺寸效应机理研究及平底立铣刀应用领域参考。

The size effect of flat end mills based on the ternary cutting force model is checked, and then a simple method estimating coefficients of cutting force is explored. The effect of helical angle on cutting force is proved to be negligible when cutting depth is little, then a simplified ternary mathematical model of force for single tooth of flat end mills is built. Based on this model, the instantaneous cutting thicknesses for every tooth are compensated with tooth run-out, and data of cutting experiments are used to fit the linear equations of peak cutting forces with cutting depth and instantaneous cutting thickness for every tooth, their R-squares are found to be near 1 as a whole, this indicates that the coefficients of cutting force for one tooth be constant, which means that the size effect of flat end mills be not significant. Accordingly, the average peak force of tool is used to estimate cutting force, with this estimation method, tool eccentricity need not to be considered, and calculation is rather simple, its simulated force waveform is close to the measured, which indicates that the estimating method be rather effective. These research results can be used as reference in the research of size effect for milling force, and in the application of flat end mills.