Product Code: JLA_15_3_172

Authors:
Andrew J. Pinkerton
Lin Li
Department of Mechanical, Aerospace, and Manufacturing Engineering, Laser Processing Research Centre, UMIST, P.O. Box 88, Sackville Street, Manchester M60 1QD, United Kingdom

In rapid tooling using the direct laser deposition process and stainless steel materials, only powders prepared using the gas-atomization method have been used because of their presumed superior flow characteristics. In this article, the use of water-atomized powder is investigated by comparing the behavior of the two types of 316 L powders, deposited using a CO₂ laser and coaxial head. Results show little difference in the pneumatic conveyance of the powders, but considerably greater absorption of laser energy by the water–atomized powder between the nozzle and material deposition point. Walls produced using the water-atomized powder exhibited a more textured microstructure and smoother sidewall surfaces, with less surface metallic oxides, but the deposition rate was considerably lower than when using gas-atomized powder. © 2003 Laser Institute of America.