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

Increasing the Productivity in Selective Laser Melting with Large Layer Thickness and Dual Laser for Ti-6Al-4V

Chen-Nan Sun1,a, Aloysius Tan1, Duy Nghia Luu1, Hang Li Seet1 Guo Ying Zheng2, Yongjie Zhang2, Andy Wei Ming Tan2 Zhen Lu3, Jia Jun Sim3 and Woon Yong Lim3

1Singapore Institute of Manufacturing Technology, Agency for Science, Technology and Research (A*STAR), 73 Nanyang Drive, 637662, Singapore

2Additive Manufacturing Development Centre, ST Engineering Aerospace Ltd., 540 Airport Road, Paya Lebar, 539938, Singapore

3SLM Solutions Singapore Pte Ltd., 25 International Business Park, #03-57/58 German Centre, 609916, Singapore


In the aerospace industry, there is an increasing demand to explore additive manufacturing (AM) to reduce the lead time and the need for inventory, especially for spare parts and maintenance, repair, and overhaul (MRO) services. However, the AM process is relatively slow due to the inherent layer-by-layer processing nature. To increase the productivity of the AM process, a variety of approaches, such as larger layer thickness and multiple beams/printheads, have been explored by various groups. In this study, we implemented large layer thickness and dual laser system simultaneously in the selective laser melting (SLM) process. Results showed that, with a layer thickness of 130 μm, the build rate of Ti-6Al-4V parts could be up to 28 mm3/s, which is about 3 to 7 times higher than conventional single beam SLM processing. The specimens were built using part hatching and contour process parameters that were optimized for high density and good surface finish. To assess the impact of large layer thickness on part quality, we also investigated the microstructures and mechanical properties of the as-built Ti-6Al-4V samples. These analyses were additionally conducted on heat-treated specimens as it is generally accepted that the α' martensite formed in SLM is brittle, which can lead to low ductility of the as-built Ti-6Al-4V specimens. Suitable heat treatments can promote the martensite decomposition to α+β lamellae, which increase the ductility and meet the elongation requirement of 10% as specified in ASTM standard F3302-18 for titanium alloys via powder bed fusion. The present study demonstrated the possibility of increasing the productivity of the SLM process without compromising the mechanical performance nor the consistency of the built parts.

Keywords: Additive manufacturing, Selective laser melting, Ti-6Al-4V, Surface roughness, Mechanical properties.

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