基于Taguchi的铜合金薄板脉冲激光弯曲成形工艺研究

Laser Bending Parameters and Control Factor Levels

为研究铜合金薄板的脉冲激光弯曲成形工艺,基于Taguchi方法对单道单次扫描成形V形件的工艺进行了正交试验设计。以弯曲角为响应目标,以望大特性的信噪比评估弯曲角的品质特性,得到了最佳工艺参数组合:激光功率P为24 W,扫描速率v为500 mm/min,离焦量L为4 mm,实验测得弯曲角为1.362°。在成形V形件的实验基础上采用多道多次扫描方式进行了预定曲率半径的圆弧曲面成形实验。依据扫描次数与弯曲角之间的关系规划了扫描路径和扫描次数,实验结果与预设目标有较好的一致性;半路径扫描比全路径扫描更能得到理想的变形效果和表面质量。实验中发现,因铜合金薄板热传导率高、厚度小,激光扫描时上下表面的温度梯度不太明显,成形机理以屈曲机理为主。

In order to study pulsed laser bending process for C194 copper alloy thin-plate, based on Taguchi method orthogonal test is adopted to form V-shape by signal scan. Using signal-to-noise ratio （larger-the-better）, the effect of the bending angle is evaluated, and the optimal combination of laser process parameters is obtained, that is, laser power is 24 W, scanning speed is 500 mm/min, defocusing amount is 4mm, and the experimental result of bending angle is 1.362°. Based on the experiment of forming V- shape, the pulsed laser forming experiment of circular-arc surface with predetermined curvature radius by repeated multiple-pass scanning is carried out. Scanning path and scanning times are planned based on the relationship between the scanning times and the bending angle, the experimental result and the presupposition target are in good agreement; ideal shape and excellent surface quality can be obtained by the method of half path scan in width. It has been found during experiments that due to high thermal conductivity and film thickness of copper alloy thin-plate, the temperature gradient between upper and lower surfaces is insignificant in the process of multiple-pass scan by pulsed laser, and buckling mechanism plays a dominant role in laser bending.