Investigation of the Correlation Between Plasma Electron Temperature and Quality of Laser Additive Manufacturing Process

In this paper, a spectral diagnosis method was reported to explore the temperature characteristic of plasma and detect the forming quality in laser additive manufacturing. The spectral data were collected by the spectrum acquisition system under different processing parameters. The plasma temperatures under different processing conditions were calculated using Boltzmann plot of six neutral iron lines between 375 nm and 390 nm, and the influence relationships between laser power, powder feeding rate, traverse speed, cladding layer and plasma temperature were found. Meanwhile, the time domain diagrams (the relationship between the temperature and time) corresponding to the process were established, in which temperatures were respectively calculated by Boltzmann double-line method and Boltzmann plot method, to analyze the correlation between temperature fluctuation and the forming defects. It was found that the results from Boltzmann plot method could reflect the generated defects more clearly.