Understanding the decisive thermal processes in laser sintering of polyamide 12

Abstract

Due to the advancements during the last decade, the laser sintering process has achieved a high technical level, which allows parts being used for Rapid Manufacturing applications. However, the processes still show a poor reproducibility of part quality. Furthermore, process interruptions or defective parts still occur regularly. The know-how and expertise needed to avoid these kind of problems is still insufficient. The temperature increase in the powder bed during laser exposure is the driving force in laser sintering of plastics. The resulting part properties strongly depend on the interaction of melt temperature and melt viscosity caused by the laser power input in the powder bed. Additionally, cooling conditions and temperature gradients in the powder bed significantly influence the accuracy and especially the warpage of parts. However, literature provides only little information on these decisive thermal processes. Therefore, additional information is necessary to improve process understanding as well as part properties in laser sintering.