Article ID Journal Published Year Pages File Type
5497422 Physics Procedia 2016 10 Pages PDF
Abstract
Residual porosity is observed in Inconel 718 samples manufactured by SLM within the optimum process window regardless the process parameters whose origin has been directly related to the starting and finishing of the laser scanning tracks. This porosity is concentrated preferentially in overlaps of fields (stripes and chessboard strategies) and borders. Location of pores has been demonstrated on long stripes, where laser stops only at borders, not in the hatch. It has been concluded that porosity is due to a high interaction time of the laser with powder which increases the energy in those points. Two different strategies have been validated to reduce this effect and thus diminish porosity. These strategies are the skywriting function, where the laser is switched off during the accelerating and decelerating portions and to increase the focus offset. The defocusing strategy is not as effective as the skywriting reducing the residual porosity.
Related Topics
Physical Sciences and Engineering Physics and Astronomy Physics and Astronomy (General)
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