A new approach to quantify powder's bed surface roughness in additive manufacturing

Optimising Spread-Layer Quality in Powder Additive Manufacturing: Assessing Packing Fraction and Segregation Tendency

“…The spreading of various metal and plastic powders was evaluated using a new tester designed specifically to analyse powder bed spreading during the PBF process [1]. The variables were the recoater shapes (two levels), gap sizes (two levels), and various powders of different materials with different sizes, shapes, and flow functions.…”

“…In order to study the relative packing fraction, and the segregation tendency of the powder bed in the AM process, a new spreader tester was designed and developed at the Wolfson Centre for Bulk Solids Handling Technology. The details of the tester was described in detail by Salehi et al [1]. The spreadability testing setup is shown in Figure 1, together with all of its features.…”

“…Powders are critical to over 50% of the UK manufacturing output, covering both large, established industries with a strong future in the UK, subject to competitiveness, and emerging manufacturing processes [1]. Powder bed fusion (PBF) procedures are a subset of additive manufacturing and 3D printing (AM3DP) processes, in which powders are melted or sintered in the manufacturing of 3D items.…”

Experimental metrics of the powder layer quality in the selective laser sintering process

“…Several recent works have been focused on the experimental assessment of the quality of spread powder layers [7,10,[26][27][28][29]. A first qualitative visual analysis of the surface quality and the layer density was proposed by Van den Eynde et al [26].…”

“…The quality of the layer surface was analysed using an image analysis tool on SEM images by detecting empty patches as proof of transient jamming [30] of the powder in the heap in front of the moving blade through the gap between the blade and the previous layer. More recently, a step forward was put using a shadowgraphy technique to highlight the surface roughness and the linear defects along the direction of spreading [28]. A promising algorithm based on single-particle detection was recently proposed by Mitterlehner et al [29].…”