汽车覆盖件拼接模具硬态铣削过程的动态特性
Dynamic Characteristics of Hard Milling Process of Splicing Dies for Automobile Cover Panel

针对汽车覆盖件拼接模具铣削过程铣削力及振动信号测试失真问题，运用经验模态分解(empirical mode decomposition，简称EMD)结合小波阈值降噪原理，对铣削力及振动信号进行降噪处理。对降噪后的振动信号进行时频域分析，研究了不同切削参数、切削进给方向对铣削拼接模具过程动态特性的影响，得到铣削方向由硬度大材料切向硬度小材料，走刀方向与拼接缝成30°夹角时铣削力突变值较小的结论。发现x，y，z方向的切削分力及振动幅值的突变值与轴向切深及进给速度呈现正相关，与切削速度是非线性关系的特性。该研究结果为汽车覆盖件拼接模具硬态铣削的工艺优化提供了理论支持。
Aiming at signal distortion of milling force and vibration during milling process of splicing dies for automobile cover panel, the empirical mode decomposition(EMD) method combined with wavelet threshold denoising method is used to denoise the cutting signal. The time-frequency domain analysis is carried out on the vibration signal after noise reduction. The influence of different cutting parameters and cutting feed direction on milling splicing die is studied. The conclusion is that when milling direction from high hardness material to low hardness material and the path of cutting is 30°to the mosaic seams, the variation value of milling force is smaller. The abrupt changes of cutting force and vibration amplitude in x, y and z directions are positively correlated with axial cutting depth and feed rate, but are not linear with the cutting speed.