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，但该类制造流程较为复杂，制备兼具高可靠性与耐用性且近乎无缺陷的构件仍是一项极具挑战性的难题。热成像技术（Thermography）是过程监测的有效工具，在金属增材制造流程中的应用价值尤为突出。由于加工过程存在高温环境，可使用常规工作于可见光光谱范围的相机开展监测。本研究中，我们将商用激光金属沉积装备在制造过程中的测量结果，分别与中波长红外相机、短波长红外相机，以及加装近红外带通滤光片的可见光高速相机的测量结果进行对比。