An investigation into the mechanisms that influence laser sintered polyamide-12 top surfaces

PurposeThe purpose of this paper is to elucidate the extent to which the mechanisms of polymer melt viscous flow and finish layer powder particle adhesion influence the top surface topographies of laser sintered polyamide (PA12) components.Design/methodology/approachLaser sintered specimens were manufactured at varying laser parameters in accordance with a full factorial design of experiments. Focus variation microscopy was used to ascertain insight into their top surface heights and peak/valley distributions. Subsequently, regression expressions were generated to model the former with respect to applied laser parameters. Auxiliary experimental analysis was also performed to validate the proposed mechanisms and statistical models.FindingsWithin the parameter range tested, this work found the root mean square (Sq) and skewness (Ssk) roughness responses of laser sintered PA12 top surfaces to be inversely related to one another, and both also principally influenced by beam spacing. Furthermore, it was demonstrated that using optimised laser parameters (to promote polymer melt dispersion) and building without finish layers (to avert subsequent powder particle adhesion) reduced the mean Sq roughness of resultant topographies by 30.8% and 47.9% relative to standard laser sintered PA12 top surfaces, respectively.Practical implicationsThe scope to which laser sintered PA12 top surfaces can be modified was highlighted.Originality/valueThis research demonstrated the impact the mechanisms of polymer melt viscous flow and finish layer powder particle adhesion have on laser sintered PA12 top surfaces.