Study on laser consolidation of metal powder with Yb:fiber laser - Evaluation of line consolidation structure

This study describes the consolidation characteristics of chromium molybdenum steel (SCM) based powder used for rapid tooling. The laser beam used was a Yb:fiber laser with a spot diameter of 45 mu m and a maximum power of 40W. In order to investigate the influence of irradiation conditions on the maximum temperature at the focal area, a two-color pyrometer developed by the authors was used. In addition, the cross section of the consolidated structure was analyzed with an electron probe microanalysis, and the cutting force was measured with a dynamometer. The result showed that the maximum temperature at the focal area was related to the consolidation characteristics of the metal powder. The main parameters which affected the consolidation characteristics were laser power and scan speed of the laser beam. The deposited powder and the plate surface were melted with generated heat and alloyed in the process of the solidification. The specific cutting force was greatly influenced by the consolidation conditions. The highest value of a specific cutting force was obtained when the melting of the powder and the solidification of the molten powder were performed repeatedly and the structure was consolidated linearly. (C) 2009 Elsevier B.V. All rights reserved.