Methodology and internal standard for powder collection in selective laser melting (SLM) AM

LORTEK has developed an in-house procedure to characterise incoming powders that can have a significant influence on the quality of samples processed by additive technologies. The methodology developed includes a particle size distribution (PSD) analysis, morphology and quantification of powders through SEM images analysis. Likewise, the in-house standard also includes the process of quantitative measurement of internal porosity content of particles from powder atomisation processes, also based on image analysis. As fluency is critical, LORTEK uses standards to measure this property with Hall flowmeter and specific devices to measure the cohesion index, which indicates the powder's ability to spread and form layers. The homogeneity of the dust layers formed is also defined by bulk density. Different analyses are carried out on dry powder. LORTEK applies its own process to remove moisture from incoming or stored powders. This is crucial factor for the smooth operation of manufacturing processes.

The standards developed enable LORTEK to determine the quality of powder and determine whether they are suitable for processing using laser-based metal additive technologies such as PBF-LB, as well as comparing different types of alloys or powder batches.