Investigation of fully dense laser sintering of tool steel powder using a pulsed Nd: Yag (neodymium-doped yttrium aluminium garnet) laser

Abstract

• For the full text of this licence, please go to: http://creativecommons.org/licenses/by-nc-nd/2.5/ SPECIAL ISSUE PAPER Investigation of fully dense laser sintering of tool steel powder using a pulsed Nd:YAG (neodymium-doped yttrium aluminium garnet) laser W-N Su * , P Erasenthiran and P M Dickens R apid M anufacturing R esearch G roup, Wolfson School of M echanical and M anufacturing Engineering, Loughborough U niversity, Loughborough, Leicestershire, U K Abstract: A 550 W neodymium-doped yttrium aluminium garnet (N d:YAG ) pulsed laser was used in the solid freeform fabrication (SF F ) process to form fully dense sintered parts. Tool steel powder was chosen due to its wide acceptance in the tool-making industry. U nlike many processes applying either thermoplastic binder or metals of low melting points in the powder mixture, this process enables a direct fusion of material to solid parts without a further post-processing step. This paper presents a methodology and the results of high-power laser sintering of tool steel powder. The investigation includes the effects of various process parameters on the fully dense laser sintering results on a single bead and single layer and the related scan strategy to build up solid cubes. This process could eventually produce pre-forms with complex material structures rather than nished tools or parts.

Evaluation of CO2 and Nd:YAG Lasers for the Selective Laser Sintering of HAPEX®

“…This is possibly due to the longer interaction time. This trend has been observed by other materials such as tool steel [22].…”

A review on selective laser sintering/melting (SLS/SLM) of aluminium alloy powders: Processing, microstructure, and properties

“…Porosity, residual stresses, and cracking as a consequence of hot shortness, and poor surface finish are among the problems associated with the SLS/SLM process as a result of the generation of uneven thermal gradients in the parts [42,56,[98][99][100][101][102]. To control the thermal gradient during powder heating and cooling and thereby fabricated unwarped and uncracked layers, various studies [42,56,[98][99][100][101][102] have investigated the relationship between scanning strategies and the properties of SLS/SLM processed parts.…”

Selective Laser Melting (SLM) of pure gold

“…As compared to the sintering of powder in some other RM processes, the complete melting of powder in SLM could produce parts with much higher density and strength. SLM has already been successfully applied to process aluminium, copper, iron, stainless and tool steel, chromium, nickel alloys, titanium and composites of these materials [1][2][3][4][5][6][7][8][9]. Gold has been used for ornaments for centuries; however, very little work has been published [10] on the laser melting of precious metals like gold and its alloys.…”