Study of keyhole behaviour for full penetration Nd-Yag CW laser welding
Study of keyhole behaviour for full penetration Nd-Yag CW laser welding
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DOI：
10.1088/0022-3727/38/12/005
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发表时间：
2005-06-21
影响因子：
3.4
通讯作者：
Briand, F
中科院分区：
文献类型：
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作者：
Fabbro, R;Slimani, S;Briand, F
对锁眼行为的理解仍然是一个非常重要的话题。在全熔透激光焊接实验中，可以很容易地分析小孔动力学。此外，如果焊接薄金属片，这种配置可以很容易地获得完整的锁孔几何形状。实际上，在这种情况下，只有一个激光束反射发生在前锁孔壁上（KW）。我们给出了这些焊接配置的研究结果，其中考虑了具有顶帽强度分布的Nd: Yag激光器。已经使用了几种诊断方法。在不同的实验条件下，利用4 kHz高速摄像机通过锁孔的顶部和底部进行轴向可视化，分析了锁孔的动力学及其完整几何形状（前壁倾角、顶部和底部孔径）。透射激光功率的测量也可以获得前KW反射率。这些结果进行比较，并用于验证我们的动态钥匙孔建模，其中包括光线追踪。最后，针对这些条件，可以建立Nd-Yag激光焊接的激光参数（入射激光功率、光斑直径）与工艺参数（材料、薄板厚度和焊接速度）之间的解析模型。
The understanding of keyhole behaviour is still a topic of great importance. The keyhole dynamics can be rather easily analysed in the case of full penetration laser welding experiments. Moreover, this configuration can allow an easy access to the complete keyhole geometry, if thin metallic sheets are welded. Indeed, in this case, only one laser beam reflection occurs on the front keyhole wall (KW). We present the results of the study of these welding configurations, where a Nd: Yag laser with a top-hat intensity distribution is considered. Several diagnostics have been used. For different experimental conditions, the dynamics of the keyhole and its complete geometry (front wall inclination, top and bottom apertures) have been analysed by using on axis visualizations through the top and the bottom of the keyhole with a 4 kHz high speed video camera. The measurement of the transmitted laser power also gives access to the front KW reflectivity. These results are compared and are used to validate our dynamic keyhole modelling, where ray tracing is included. Finally, for these conditions, an analytical model can be proposed that relates the laser parameters (incident laser power, spot diameter) with the processing parameters (material, sheet thickness and welding velocity) for Nd-Yag laser welding.