真实刀刃轨迹下的涡旋齿周铣瞬时厚度模型

Instantaneous Thickness Model For Circular Milling of Scroll Teeth Based on Real Tool Path

通过对直线铣削和圆周铣削特点的分析,建立了圆周铣削坐标系下刀刃轨迹方程,推导了改进几何法铣削厚度计算模型,结合真实刀刃轨迹和切削几何条件建立了涡旋齿圆周铣削瞬时厚度计算模型。该模型反映了工件、刀具和铣削参数的综合影响,可分别用于定量计算涡旋齿内、外壁铣削厚度。计算分析结果表明:刀具中心转角θ增大,瞬时铣削厚度先增大后减小,刀具中心转角θ=1.6rad时外壁瞬时铣削厚度达到最大值0.162mm,内外壁铣削厚度差值为21%;随着涡旋齿型线曲率半径增大,瞬时铣削厚度线性增加;刀刃齿数越少,瞬时铣削厚度越大;瞬时铣削厚度随着进给角速度的增大而迅速增大,随着主轴角速度的增加而呈减小趋势,当主轴角速度增大到100πrad/s以上时,瞬时铣削厚度趋于稳定。

The equation of real tool path in circular milling coordinate system is established based on the characteristics of tradi⁃tional linear milling and circular milling,then the improved geometric model for calculating milling thickness is deduced.Based on the real tool path and cutting geometric conditions,the instantaneous chip thickness calculation model for circular milling of scroll teeth is presented.The model reflects the comprehensive effects of workpiece,cutter and milling parameters on the chip thick⁃ness,and can be used to calculated quantitatively the chip thickness both of inner and outer wall of scroll teeth.Results show that the instantaneous chip thickness increases first and then decreases with the increase of the center angle of the cutter,and the in⁃stantaneous chip thickness of the outer wall reaches 0.162mm when the center angle of the cutter approaches 1.6rad,and the maxi⁃mum difference between the inner and outer wall thickness reaches 21%;With the increase of the curvature radius of the scroll pro⁃file,the chip thickness increases linearly;The smaller the number of cutter teeth,the bigger the instantaneous milling thickness;The instantaneous chip thickness increases rapidly with the increase of feed angle speed and decreases with the increase of spindle angular velocity.When the angular velocity increases above 100πrad/s,the chip thickness tends to remain stable.