In-situ monitoring of a laser metal deposition (LMD) process: comparison of MWIR, SWIR and high-speed NIR thermography

Additive manufacturing offers a range of novel applications. However, the manufacturing process is complex and the production of almost defect-free parts with high reliability and durability is still a challenge. Thermography is a valuable tool for process surveillance, especially in metal additive manufacturing processes. The high process temperatures allow one to use cameras usually operating in the visible spectral range. Here, we compare the results of measurements during the manufacturing process of a commercial laser metal deposition setup using a mid wavelength infrared camera with those from a short wavelength infrared camera and those from a visual spectrum high-speed camera with band pass filter in the near infrared range.

增材制造（Additive Manufacturing）具备诸多新颖应用场景。然而，其制造流程复杂，制备出兼具高可靠性与耐久性且几乎无缺陷的构件仍是一项核心挑战。热成像（Thermography）技术是过程监测的有效手段，在金属增材制造流程中尤为实用。由于该工艺温度较高，可采用常规工作于可见光光谱范围的相机开展监测。本研究中，我们对比了商用激光金属沉积（laser metal deposition）设备在制造过程中的测量结果：分别使用中波长红外相机、短波长红外相机，以及搭载近红外波段带通滤波器的可见光高速相机进行采集，并对所得数据进行比对分析。