Benchmarking of different SLS/SLM processes as Rapid Manufacturing techniques

Abstract

Recently, a shift of Rapid Prototyping (RP) to Rapid Manufacturing (RM) has come up because of technical improvements of Layer Manufacturing processes. Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) techniques are no longer exclusively used for prototyping and the possibility to process all kind of metals yields opportunities to manufacture real functional parts, e.g. injection moulds (Rapid Tooling). This study examines different SLS/SLM processes with regard to conditions that become very important for manufacturing, such as accuracy, material, mechanical properties, speed and reliability. A benchmark model is developed facilitating to test these conditions and to check the process limitations. This benchmark is manufactured by five SLS/SLM machines which differ in process mechanism, powder material and optimal process parameters. To find out process accuracy, a dimensional analysis is performed and the surface roughness is measured. Besides, the benchmarks are tested for their mechanical properties such as density, hardness, strength and stiffness. Finally, speed and repeatability are discussed as important factors for manufacturing. This paper presents the state of the art in SLS/SLM and aims at understanding the limitations of different SLS/SLM processes to form a picture of the potential manufacturing applications of these processes.