A review of monitoring and control system for laser metal wire additive manufacturing

Laser metal wire additive manufacturing as a directed energy deposition technology has a good development prospect. This paper summarizes and reviews the monitoring and control systems for laser metal wire additive manufacturing at home and abroad at this stage. At present, the common monitoring systems for laser metal wire additive manufacturing at home and abroad include structural light scanning system, infrared temperature imaging system, etc., which can monitor the deposition layer height and melt pool state in real time; the common control systems are online feedback wire feeding rate control system and online feedback laser power control system with closed-loop control strategy, etc. The online monitoring system and control system can work together to significantly optimize the additive process and forming quality. The online monitoring system and the control system work together to significantly optimize the additive process and the forming quality. In addition, this paper also introduces the emerging laser metal wire additive manufacturing monitoring technologies, including 3D ultrasonic scanning technology and electromagnetic vibration monitoring technology. Finally, this paper provides an outlook on the next generation of monitoring and control systems in the context of the process challenges of laser metal wire additive manufacturing technology. At present, monitoring objects such as deposition layer height and width, melt pool size and temperature have been more fully researched and experimentally demonstrated at home and abroad, but in the deposition process, the high energy density of the laser causes high temperature gradients, so the research of online high-precision and high-quality monitoring and control technologies for the deposition process becomes crucial.Highlights: Laser metal wire additive manufacturing requires high forming accuracy, while domestic and foreign research on the technology related to the process, forming in-situ control is in its infancy, and in-depth research on real-time monitoring and control of the deposition layer and melt pool deviation has important practical significance.