選択的レーザ溶融法におけるレーザ走査パターンがSUS630の材料特性に及ぼす影響

抄録

Additive manufacturing; AM is getting attention in manufacturing field because it can fabricate complex forms from 3D data directly. Selective laser melting; SLM, one of AM, is a method that can fabricate metal parts and used for fabricating aerospace parts. Some SLM machines apply Checker flag, a laser scan strategy that partition laser scan areas into geometric shapes, to reduce residual stress. In previous studies, effects of laser conditions on material properties were investigated a lot, but effects of laser scan strategy were not investigated. Therefore, the aim of this study is to research effect of laser irradiation pattern on material properties. Four types of laser scan strategies (N; melting by normal pattern, C; melting by checker flag, DN; melting twice by the normal pattern, DC; melting twice by the checker flag) were prepared. Cube specimens were fabricated using each type of laser scan strategies by SLM machine ProX300 (3D Systems, US). Then, laser power and scan speed were changed. Densities of specimens were measured and polished surface were observed. In the results, high density was observed with energy density of more than 125 J/m in N and C, and 100 J/m in DN and DC. Density of each specimens used checker flag was higher than Normal pattern. Double scan let the gas escape and reduced micro voids in specimens. Among those four types of specimens, the method melting twice by the checker flag got the highest density and reduced micro voids.