A 316L stainless steel [SS316L] plate was fabricated without pores by selective laser melting (SLM) in a vacuum. SS316L has excellent properties such as high corrosion resistance and hardness, but forming complicated structures is challenging due to difficulties working the material. SLM forms a 3D material by building it layer by layer. In SLM process, a denudation zone is caused to form near the laser scan path while laser irradiation. The denudation zone caused to form a layer having an un-uniform thickness and also leads to a decrease accuracy of fabrication. There are many unknown controlling factors about the basis of denudation zone generation. In this study, in order to clarify the mechanism of the denudation zone formation process, SS316L is fabricated by SLM in a vacuum and the width of denudation zone is measured by microscope. The ambient pressure is varied from 10 Pa to 10 ⁵ Pa using a vacuum pump, and argon gas. As the results, at the ambient pressure of 10⁵ Pa, the width of denudation zone is 0.81 mm, and the width of denudation zone at 300 Pa was improved to 0.27 mm. It is clarified that the width of denudation decreases with the decrease of the ambient pressure.
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