Development of Micro Selective Laser Melting: The State of the Art and Future Perspectives

Additive manufacturing (AM) is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials. Selective laser melting (SLM) is a common AM technique that is based on powder-bed fusion (PBF) to process metals; however, it is currently focused only on the fabrication of macroscale and mesoscale components. This paper reviews the state of the art of the SLM of metallic materials at the microscale level. In comparison with the direct writing techniques that are commonly used for micro AM, micro SLM is attractive due to a number of factors, including a faster cycle time, process simplicity, and material versatility. A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering (SLS) is conducted. In addition to identifying existing issues with SLM at the microscale, which include powder recoating, laser optics, and powder particle size, this paper details potential future directions. A detailed review of existing recoating methods in powder-bed techniques is conducted, along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain. A number of secondary finishing techniques for AM components are reviewed, with a focus on implementation for microscale features and integration with micro SLM systems. (C) 2019 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company.