覆盖件模具拼接特征对球头刀铣削振动的影响

为了分析曲面拼接特征对振动的影响,建立了考虑拼接特征、曲面特征的未变形切屑厚度模型;基于曲面拼接区的未变形切屑厚度建立了考虑时滞变化的铣削动力学模型,通过数值计算综合分析了过拼接缝时冲击振动、刀具轴向位置角、拼接缝宽度对铣削振动的影响;最后基于淬硬钢曲面拼接铣削实验验证了考虑曲面拼接特征的铣削振动预测模型的准确性,并基于不同拼接特征下的铣削振动计算出了相应的加速度信号幅值和分形维数。研究结果表明:淬硬钢曲面拼接特征使铣削振动的非线性特征减弱,某一频段的振动能量集聚,据此情况可分析出不同拼接特征下的最佳加工工艺参数。

Influences of Splicing Characteristics of Cover Panel Moulds on Milling Vibrations with Ball End Tools

In order to analyze the influences of the curved surface splicing characteristics on vibrations, an undistorted chip thickness model was established considering splicing characteristics and surface characteristics. Based on the undistorted chip thicknesses in the splicing areas of curved surfaces, a milling dynamics model was established considering the change of time delay. Through the numerical calculations, the influences of impact vibrations during the splicing seams, tool axial position angles and splicing seam widths on milling vibrations were analyzed comprehensively. Finally, based on the curved surface splicing milling experiments of hardened steels, the accuracy of milling vibration prediction model was verified considering the splicing surface characteristics. At the same time, the corresponding vibration acceleration signal amplitudes and fractal dimensions were calculated based on the milling vibrations under different splicing characteristics. The results show that the nonlinear characteristics of milling vibrations are weaken by the splicing characteristics of hardened steel surfaces, and vibration energy is concentrated in a certain frequency band. According to this situation, the optimal processing parameters may be analyzed under different splicing characteristics.