Measurement on Temperature Distribution of Metal Powder Stream in Laser Fabricating

摘要

In order to study temperature distribution of metal powder stream in laser fabricating, its thermal radiation in visible region was detected by CCD. Based on Planck's radiation law, the relation between molten powder temperature and its visible thermal radiation could be set up. The thermal radiation image signal of powder stream was transformed to digital signal which was used to analyzing its temperature distribution. It was shown that crosswise dimension of molten powder was about 2.5 mm in diameter at the distance of 5 mm from power nozzle. The powder out from powder nozzle was heated rapidly by laser. Temperature of powder in central axis regions was the highest which was nearly 2000K at the power of 1100w. The temperature gradient of powder at the edge of laser stream was greatly. The measurement results could be used to optimize the design of powder nozzle and processing parameters of laser fabricating.