考虑曲面特性的凸曲面铣削稳定性研究

Exploring Milling Stability of Convex Surfaces with Surface Characteristics Considered

在凸曲面模具铣削加工过程中,由于曲面特性复杂,刀-工接触关系沿切削轨迹不断变化,刀具刃口受到交变载荷加剧了铣削过程刀具磨损的程度,使得模具加工效率大幅度降低。针对上述问题综合考虑曲面曲率以及刀具前倾角对铣削稳定性的影响,并建立了考虑曲面曲率、刀具前倾角的瞬时切屑厚度模型,在求解铣削系统稳定性时运用计算效率更高的基于龙格库塔法的全离散法,深入研究了曲面特性对铣削稳定域的影响。得到以下结论:随着曲率半径的增加,极限切深减小,铣削稳定性降低;随着刀具前倾角的增加,稳定性叶瓣图整体向左移动。基于凸曲面铣削试验,对实验结果进行时域、频域分析验证了铣削稳定性预测的准确性。

In milling a convex surface die, because of its complex surface characteristics, the cutter-worker contact relation changes with the cutting trajectory. The tool edge is subjected to alternating load to increase the degree of tool wear in the milling process, thus reducing the die machining efficiency. In view of the above problems, the influence of curvature radius and lead angle on milling stability should be considered. In this paper, the instantaneous chip thickness model with the curvature of curved surface and the lead angle of the tool considered is established. The Runge-Kutta-based complete discretization method is used to solve the milling stability of the system, and the influence of the surface characteristics on the stability lobe map is studied in depth. The following conclusions are reached: the milling stability decreases with the increase of curvature radius and the stability prediction curve is shifted to the left as the lead angle increases. Finally, time-frequency analysis is used to verify the correctness of the stability prediction curve based on the convex surface milling test.