Modeling the Effect of Scan Path of Thermal Gradients during Selective Laser Melting via Finite Element Analysis
As industry competition and increasingly stringent safety concerns drive the need for increased part performance and decreased part weight, additive manufacturing methods are being turned to as an innovative fabrication method able to produce more complex parts. Despite significant advances in technology since the inception of additive manufacturing in 1980, high thermal gradients during part manufacture can generate residual stresses, part deformation, and even part failure due to cracking. Among other factors such as laser power and speed, scan path directly affects the thermal gradients during manufacturing. The work in this thesis compares the thermal gradients generated by nine different scanning methods; six of which have been tested and discussed in previous literature, and three of which are new paths proposed for the first time in this document. A finite element model was created and validated in order to easily test all nine paths, while keeping machine parameters such as hatch distance and laser power constant for all tests. This model can change machine parameters and scan paths easily, and has the ability to change scan paths between layers. The tests found that scan paths that subsection powder layers into smaller areas before scanning produce lower thermal gradients than those that scan the full layer without sectioning. One of the new scan path concepts, deemed the “subsectioned spiral method”, produced the most favourable results most consistently when compared to the other eight paths, and shows signs of being an effective scan path that could outperform the other methods used widely today.
URI for this recordhttp://hdl.handle.net/1974/27484
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