Three degrees of freedom stability analysis in the milling with bull-nosed end mills
Three degrees of freedom stability analysis in the milling with bull-nosed end mills
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DOI：
10.1007/s00170-015-8144-5
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
R. Yan;Yanhong Gong;F. Peng;X. Tang;Hua Li;Bin Li
中科院分区：
文献类型：
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作者：
R. Yan;Yanhong Gong;F. Peng;X. Tang;Hua Li;Bin Li
采用圆头米尔斯铣刀加工异形零件偏心支架时，切屑再生机理受刀具与工件三个方向相对振动的影响。本文建立了三自由度稳定性分析模型，考虑了刀具和工件的动力学特性。为了得到动力学方程，根据刀具与工件之间的相对振动特性，提出了一种通用的矢量法来计算无穷小切屑槽在三个方向上的动态切屑厚度。介绍了一种用逐点检值法来判断微切削槽是否切削的方法。采用全离散化方法求解动力学方程。由于薄壁结构的动力学特性随位置的变化而变化，不同位置处的稳定波瓣存在显著差异。稳定波瓣表明，薄壁端部的稳定极限低于薄壁中部的稳定极限。在GMC 1600 H/2五轴联动加工中心上进行了外圆角立米尔斯铣刀铣削薄壁件的三自由度稳定性验证实验。预测的三个自由度的稳定性波瓣与实验结果吻合良好。为了进行比较，在使用相同刀具铣削接骨板时证明了两个自由度稳定性的可行性。
When bull-nosed end mills are applied to machine the eccentric brackets of special-shaped parts, the chip regeneration mechanism is influenced by relative vibrations between the cutter and the workpiece in three directions. Three degrees of freedom stability is modeled analytically in this paper, in which dynamics of the cutter and the workpiece are both taken into consideration. In order to obtain the dynamic equation, a universal vector method is proposed to calculate dynamic chip thickness of the infinitesimal cutting flute in three directions based on the characteristics of relative vibrations between the cutter and the workpiece. A checking value point-by-point method is introduced to determine whether the infinitesimal cutting flute is in cutting or not. The full-discretization method is adopted to solve the dynamic equation. Since the dynamics of the thin walls is varied with the position, there exists a significant difference in the stability lobes at different positions. The stability lobes show that the stability limit at the end of the thin walls is lower than that in the middle of the thin walls. The verification experiments of three degrees of freedom stability were conducted in milling thin walls with the bull-nosed end mills on the five-axis machining center GMC 1600 H/2. The predicted three degrees of freedom stability lobes agree well with the experimental results. For comparison, the viability of the two degrees of freedom stability is proven in milling the plate with the same cutters.