大功率Nd:YAG激光深熔焊接过程中同轴辐射光的采集

Collection of Coaxial Emission in High Power Nd:YAG Laser Deep-Penetration Welging

同轴信息监测是一种直接对熔池和小孔进行监测的方法。本文介绍了激光深熔焊接过程中 ,同轴信号的采集原理和光路设计 ,利用同轴信息采集光路的激光焊接镜头采集了大功率Nd :YAG激光焊接过程中辐射的同轴光信号。对Q2 35钢激光深熔焊接过程中 ,从焊接熔池和等离子体中辐射的同轴光谱曲线是以连续谱为背景谱 ,当焊接参数的变化时 ,同轴辐射光的相对光强发生变化 ,而其与波长的对应关系没有变化。在激光深熔点焊过程中同时采集了同轴和水平辐射的光强信息 ,对比发现二者具有不同的峰值波长 ,并且在 5 5 0nm～ 5 80nm的波段内 。

Coaxial information monitoring is a method to directly monitor the welding pool and keyhole in laser deep-penetration welding process. In this paper, mechanism of collecting coaxial information in laser welding is introduced, the setups of light path for collecting coaxial emission light is analyzed. The radiation spectrum of welding pool (keyhole) and plasma which is coaxial with laser is collected by using laser welding optics with collecting light path of coaxial emission. The coaxial spectrum of Q235 carbon steel with laser deep-penetration welding is continuous. When welding parameters vary, the relative intensity of coaxial emission will fluctuate, but the relationship between the relative intensity of coaxial emission and its wavelength keeps invariable. In addition, the coaxial and horizontal emission are collected at the same time. Their comparison indicates their peak wavelengths are different and the contrast between their relative intensity is visible in 550nm～580nm. It is the first time to realize the coaxial information collecting for high power Nd:YAG laser welding in China.