Scan strategy in electron beam selective melting

In electron beam selective melting process, powder pushed-away phenomena and uneven temperature field are two main obstacles, which are greatly associated with the electron beam scan mode. In this paper, various scan strategies, including iterative scan mode, reverse scan mode, interlaced reverse scan mode, randomized block scan mode, and constant length scan mode, are investigated. The analyses for each scan strategy are presented based on the influence to the temperature field over the formation zone and the powder pushed-away phenomena. The most promising strategy, interlaced reverse scan mode, is approved by the ANSYS simulation and a two-dimensional scan experiment. The result shows interlaced reverse scan mode can improve the uniformity of the temperature field and reduce the powder pushed-away phenomena.