A quantitative, image-based analysis of the spreading performance of PolyArylEtherKetone polymer powders during Powder Bed Fusion Additive Manufacture

Powder spreadability in the powder bed fusion process is normally visually assessed by the machine operator through repeat trials at room temperature or elevated temperatures. Some studies used powder rheology results as an indicator of the powder spreadability. This study presents a novel method of image-based analysis for the assessment of polymer spreading quality for powder bed fusion and demonstrates that the subjective assessment of the machine operator can be replaced by quantitative and measurable data. Twenty-four developmental grade PolyArylEtherKetone powders were tested. Images of the powder bed surface were analysed in MATLAB and the relationships with the powder rheology established through statistical analysis. The two methods for calculating surface deviations from variations in the greyscale images showed to be sensitive to the recoater travel and presented a strong correlation with the Normalised Aeration Sensitivity (NAS), a powder rheology parameter identified in a previous study as the most significant parameter able to categorise powder flow and spreadability based on a yes/no response. • PolyArylEtherKetone powders are assessed for polymer Powder Bed Fusion. • Bespoke powder spreading apparatus enables image capture during spreading. • Variable flow properties create defective powder surfaces. • Two methods created in MATLAB to quantify the surface quality. • Surface quality data correlates with powder rheometer key values.