Comparative Analysis of Particle Size Distribution Measurement Techniques in Additive Manufacturing: A Case Study on Stainless Steel Powder

The success of powder-based AM heavily depends on the intrinsic properties of metallic powders, particularly their particle size distribution (PSD). PSD plays a critical role in ensuring the quality, stability, and repeatability of AM results, demanding accurate PSD determination for selecting suitable powders and consistently producing high-quality printed parts. Multiple techniques are available for measuring PSD, each based on distinct physical principles and sensitive to different aspects of a particle's size and shape. This variability can lead to discrepancies in PSD measurements obtained from different methods, making it challenging to compare and interpret results across techniques. In this study, three commonly used methods for measuring PSD in the powder metallurgy field are compared: sieve analysis, dynamic image analysis (DIA) and laser diffraction (LD). The study analyzes two batches of stainlesssteel powders (AISI 316L) with size distributions ranging from 20 µm to 63 µm and 63 µm to 150 µm. The morphological characteristics of the powder particles were examined using scanning electron microscopy (SEM). The powders predominantly consist of spherical particles, with a small proportion of irregular, elongated, and attached satellite particles. Sieve analysis is effective for larger particles but limited for finer sizes and is influenced by sieve tolerances. DIA provides detailed metrics on both particle size and shape, offering morphology information about the powder. LD, while fast and highly automated, tends to overestimate particle size, particularly for coarser fractions, due to its assumptions about particle sphericity and the influence of particle morphology. The study found that a good correlation between DIA and sieve analysis results can be achieved when evaluating predominantly spherical particles and using appropriate size metrics.