Determination of Optimal Processing Conditions for the Production of Polyamide 11 Parts using the Laser Sintering Process

Abstract

Due to the advancements during the last decade, the laser sintering process has achieved a high technical level, allowing for Rapid Manufacturing of parts in some applications. However, only few polymers are commercially available for the process. Polyamide 12 dominates the market with share of nearly 90 %. Other laser sintering materials differ in part properties from PA 12. Therefore, they are more suitable for some specific applications. Within these, Polyamide 11 has the highest distribution on the market. PA 11 offers some advantages like significant higher part ductility but also some disadvantages like more warpage or higher processing temperatures. However, literature provides in general only little information on the processing of PA 11 and how to achieve optimal processing conditions. A DOE approach using the response surface methodology was utilized to study the correlations between process parameters and part properties. Laser power, scan speed, hatch distance, layer thickness and outline energy density were varied in order to improve the part quality considering mechanical properties, surface roughness and part density. Additionally, results for process influences and part properties were compared with those found for Polyamide 12 in order to derive general correlations. Based on the performed study, optimized process parameter sets are established for PA 11 resulting in improved part properties.