SUNConferences, 17th Annual Conference of the Rapid Product Development Association of South Africa

Font Size: 
THE EFFECTS OF SCAN STRATEGIES ON SELECTIVE LASER MELTED PARTS
Devon Hagedorn-Hansen, Martin B Bezuidenhout, Jan Wilkens, Philip A Hugo, Gert A Oosthuizen

Last modified: 2016-10-12

Abstract


The utilisation of Additive Manufacturing (AM) for the production of intricate part geometries in the aerospace, medical, and tool-and-die industries is increasingly considered for incorporation in manufacturing process chains. It is important to note that AM also bears certain disadvantages, one of which is geometrical deviations within parts. Warping of parts is ascribed to the presence of high temperature gradients as well as the melting and solidification rates within the two dimensional layers, leading to the induction of residual stress. The Selective Laser Melting (SLM) process is generally characterised by high scan speeds and high thermal gradients which results in high cooling rates of the scanned part. The high cooling rates lead to non-equilibrium microstructures as well as warping of the melted layer. This paper discusses the effects of the thermally induced residual stress on the geometric deviation of titanium parts. Different scan strategies were performed on a single layer of powder and the deviation due to warping was measured using image processing software. The measurements were compared to each other and the best strategies were revealed.