Development of advanced selective laser melting method by approach of laser heat input control

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05079
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Osaka University
• Principal Investigator: Sato Yuji 大阪大学, 接合科学研究所, 准教授 (40422547)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: レーザ金属積層造形 / チタン / 変調パルス / ファイバ―レーザ / スパッタ / 異方性 / 材料組織制御 / 入熱制御

Outline of Final Research Achievements

Selective laser melting (SLM) is a powder bed fusion method that uses a laser as a heat source to melt and solidify powders to form two-dimensional shapes, which are then stacked to form three-dimensional shapes. However, the SLM method has some problems. One is spatter generation while the laser irradiation, another one is generation of anisotropy. To solve these problems, it required to control the heat input of laser precisely. In this study, it was attempted to precisely control the heat input by using modulated pulse that are periodically turned on and off for output power of the laser.　As a result, it was found that the grain size tended to be smaller in the fabrication using modulated pulses of laser. Furthermore, the specimens fabricated with a pulse frequency of 100 Hz were found to have a homogeneous in microstructure.

Free Research Field

レーザ加工

Academic Significance and Societal Importance of the Research Achievements

レーザをパルス駆動させてレーザの入熱量を精密に制御して積層造形を行った本研究では、レーザパルスのピーク出力やパルス波形の違いが粉末粒子の溶融凝固プロセスに与える影響を微視的にリアルタイム観察し、スパッタの発生因子との相関を明らかにした。さらに、パルスレーザを用いてチタン合金の積層造形を行い、3D造形物の異方性解消、材料組織の均質化など、変調パルスレーザによる入熱制御技術が３D造形の高品質化につながる基礎的な結果を得た。本成果は次世代生産技術の根幹となる金属積層造形法の高度化に資するものとなり、ものづくりのデジタル化の推進に大きく寄与するものであると考える。