Page 94 - ESAM-1-2

Engineering Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Impact of machine factors on the surface quality

of parts fabricated via powder bed fusion

1
Zhen Lu 1 , Ming Jen Tan * , Yi Zhang 2 , Jia An 3 , and Chee Kai Chua 3
1 Singapore Centre for 3D Printing, Nanyang Technological University, Singapore
2 School of Integrated Circuit Science and Engineering, University of Electronic Science and
Technology of China, Sichuan, China
3 Engineering Product Development Pillar, Singapore University of Technology and Design,
Singapore

Abstract

In the growing additive manufacturing industry, there is increasing demand for
improved as-built surface quality of parts fabricated by the powder bed fusion
(PBF) process, particularly in the aerospace, medical, and tooling industrial sectors.
The surface finish of PBF parts is often suboptimal due to the inherent layer-by-
layer fabrication process. Depending on the material used, the average surface
roughness (Ra) of PBF components typically ranges from 5 to 50 μm. To address
this issue, various strategies have been investigated, including optimizing printing
process parameters, refining support designs, and upgrading laser hardware. In this
study, we investigated the machine factors on the as-built surface quality of parts
*Corresponding author: in the PBF process. Fully dense as-built 1.2709 tool steel parts were produced with
Ming Jen Tan a relative density of 99.9% using platform pre-heating. Without heat treatment, the
(mmjtan@ntu.edu.sg) as-built part exhibited an ultimate tensile strength of 1,135 ± 75 MPa, yield strength
Citation: Lu Z, Tan MJ, Zhang Y, of 915 ± 120 MPa, and an elongation of 12 ± 3%. Vickers hardness was measured at
An J, Chua CK. Impact of machine 339 ± 35. Surface measurements were performed on parts placed across the substrate
factors on the surface quality
of parts fabricated via powder plate, with the Ra of as-built vertical walls averaging 22.6 ± 11.9 mm. Results showed
bed fusion. Eng Sci Add Manuf. that the surface quality of as-built 1.2709 tool steel parts, with a layer thickness of
2025;1(2):025240014. 30 μm, was significantly affected by their distance from the inert gas outlet and the
doi: 10.36922/ESAM025240014
laser center. This study demonstrates that the as-built surface quality of PBF parts can
Received: May 13, 2055 be controlled through more effective build job preparation without changing key
Revised: June 14, 2025 processing parameters.
Accepted: June 18, 2025
Keywords: Additive manufacturing; 3D printing; Powder bed fusion; Selective laser
Published online: June 24, 2025
melting; Surface quality; Tool steel
Copyright: © 2025 Author(s).
This is an Open-Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution, 1. Introduction
and reproduction in any medium,
provided the original work is Additive manufacturing (AM), as defined by International Standardization Organization/
properly cited. ASTM 52900:2021, is the process of joining materials to make parts from 3D model
1
Publisher’s Note: AccScience data. Usually, materials are joined layer upon layer, as opposed to subtractive and formative
Publishing remains neutral with methods of manufacturing. Seven families of AM are commonly recognized, while powder
regard to jurisdictional claims in
published maps and institutional bed fusion (PBF) uses lasers as the energy source to fully melt and fuse the metal powder
affiliations. materials directly to form the near-net shape metal product, which can be fully functional.

Volume 1 Issue 2 (2025) 1 doi: 10.36922/ESAM025240014