Surface roughness of polyamide 12 parts manufactured using selective laser sintering

Abstract

Selective laser sintering (SLS) is an additive manufacturing technique that has become increasingly prevalent in today's rapidly advancing production industries. SLS utilizes a layer-by-layer processing technique that allows for complex geometries to be produced without expensive tooling or molding. Because of the technology's widespread use in fulfilling functional demands, parts produced by SLS should have a good surface quality. However, parts manufactured via SLS have a comparatively higher surface roughness than alternative manufacturing methods. To better understand the various factors that affect surface roughness, a design of experiments was implemented which investigated the effects of four process parameters using a Sinterstation 2500, a commercial SLS printer: laser power, roller speed, powder type, and scan spacing. To draw a comparison with other SLS systems, two process parameters were investigated on a Sinterit Lisa, a desktop SLS printer: power ratio and powder type. These effects were studied across the entire powder bed, a study of which has not been previously conducted. Since many other factors play a role such as layer height, this study concentrated on the top surface of the SLS printed part. The surface roughness of the produced parts was studied using Focus Variation (FV) technology. Conditional formatting was used to show the surface roughness and area ratio of the powder bed, and an analysis of variance (ANOVA) is performed on the data collected from the Sinterstation.