The effect of inter- and intra-layer delay time on TPU parts fabricated by laser powder bed fusion
摘要
In polymer laser powder bed fusion (PBF-LB-P) techniques, such as laser sintering, the time between scanning a given point in one layer and the same x-y point in the next layer is known as the ‘inter-layer delay time’. Multiple parts are normally fabricated in a PBF-LB-P build for efficiency; however, this leads to variation in the inter-layer delay time for individual parts; in this study, we present a specific investigation using a commercially available thermoplastic polyurethane (TPU). Multiple part layouts were used and the resulting parts were subject to tensile testing and fracture surface analysis. The results demonstrate that an increase in inter-layer delay time can lead to a significant reduction in mechanical properties. Fabricating specimens in groups of 5 led to a 10% reduction in ultimate tensile strength, 30% reduction in extension at break, and 15