A Statistical Study of Surface Roughness for Polyamide 12 Parts Produced Using Selective Laser Sintering

Abstract

Selective laser sintering (SLS) of thermoplastic powders allows for the creation of parts with complex geometries and functionally robust designs. Based on the principle of selectively fusing regions in a layer-by-layer process, SLS has gained increasing interest as an economical way to supplement small batch production for traditional manufacturing techniques. To introduce SLS parts into functionally demanding applications, it is imperative that they exhibit good surface quality to prevent wear caused by surface friction. Parts produced with SLS, however, typically have a higher surface roughness than those produced through traditional manufacturing techniques. Understanding the relationship between processing parameters and surface quality will allow one to better predict and control surfaces for end-use parts. A design of experiments was formulated to investigate the effects of four process parameters on parts produced across the powder bed: powder type, roller speed, laser power, and scan spacing. To analyze the surface roughness and area ratio of the parts, Focus Variation (FV) technology was implemented. Statistical models were developed to estimate the surface roughness and area ratio of manufactured specimens.