Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Quality of Additively Manufactured As-built 17-4 PH Parts with respect to Process Conditions and Moisture Contents

Taehwan Kim1, Min-Kyeom Kim1, Juwon Kim1, Dongwon Kim11, Jonghwan No1,2 and Jonghwan Suh1

1Department of Mechanical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Gyeonggi-do, Republic of Korea

2Global Technology Center (GTC) Mold Solution, Samsung Electronics, Amko-ro 70, Gwangsan-gu, Kwangju, 61010, South Korea


Laser powder bed fusion (LPBF) is one of the most commonly used additive manufacturing (AM) techniques using a scanning laser. This is because the complex structures and the high resolution can be attained compared with the other metal AM techniques. During the manufacturing process, process failures and defects, such as crack, delamination, low relative density, etc. occur because of the environment of the chamber/air, the inappropriate process conditions, and the condition of the metal powders. Among them, it has been reported that moisture has a detrimental influence on the qualities such as low powder flowability, agglomeration, hydrogen pores, oxidation of powder surface, etc. However, a fundamental understanding of the moisture effects on the qualities and properties of as-built parts is still lacking. Therefore, in this study, the quality of the as-built 17-4PH stainless steel parts is quantitatively analyzed via ex-situ characterization of the relative density, hardness, and melt-pool geometry, while varying the moisture contents and processing parameters. As a result, the moisture caused detrimental effects on material properties in terms of relative density, hardness, and melt-pool geometry. Also, lack of fusion and detachment from the previously fabricated layer induced by agglomeration of each metal particle occurred with higher moisture contents. This work showed how much the moisture affected the quality of the as-built 17-4 PH parts combined with the processing parameters. The results confirmed that the management of moisture is indispensable for printing

Keywords: Laser powder bed fusion, Additive manufacturing, Ex-situ characterization, Material properties, Moisture effects.

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