Research status of on-line monitoring of laser metal deposition

Abstract

The process of laser metal deposition was easy to be affected by fluctuations of environment and process parameters, leading to the deviation of melt pool temperature or deposition morphology and so on. Accumulation of small deviation would result in the instability of deposition process and lead to the failure of forming. Therefore, the on-line monitoring of laser metal deposition process was studied, involving thermal history of forming parts, temperature and size of melt pool, deposition morphology and forming defects, and so on. In this paper, the on-line monitoring technologies, such as thermocouple temperature measurement, infrared thermal imaging, high-speed camera and other monitoring methods, were introduced, and the open-loop monitoring, closed-loop feedback control and closed-loop feedforward control technologies were illustrated in detail. According to the research situation, the future development of on-line monitoring in laser metal deposition was prospected.