Characterization of Selective Laser Sintering™ Materials to Determine Process Stability
Abstract
The Selective Laser Sintering (SLS) process has proved to be an excellent method for
prototyping functional parts out of engineering thermoplastics such as polyamides. However, the
material undergoes physical and chemical changes due to repeated heating cycles in the SLS
equipment. This causes variations in powder characteristics and performance in the SLS process.
With the increased utilization of SLS for direct manufacturing it is necessary to develop a
characterization and testing system that can determine powder fitness to ensure process stability
and part quality. Current powder recycling methodologies use an average virgin-to-used powder
mixture. In a new approach, a testing mechanism to deliver a numerical, measurable material
characterization will be discussed. Experimental results of repeated reuse of material and its
resulting physical effects on mechanical properties, shrinkage, and chemical tests will be
presented. A definitive testing and measurement process control will be shown to improve
process stability and thus part quality and consistency.