Dynamic depreciation for parts produced using laser-based powder bed fusion of polymers

Abstract

Laser-based powder bed fusion of polymers (PBF-LB/P) is one of the most widely used additive manufacturing technologies for producing complex and customized components. One of the key aspects of this process is the recycling of the powder, which is central to the technology’s overall efficiency. During reuse cycles, the powder undergoes inevitable chemical, physical and mechanical changes that directly affect the quality of the final artifacts. This directly impacts process sustainability and production costs. The Sum-of-the-Year’s Digits (SOYD) depreciation model, which has been proposed in the literature for metal powders, assumes an initial moderate decline in value, followed by a slower decline upon reuse. However, polymer powders can degrade more quickly than metal powders, reaching a point of no return sooner. Therefore, the SOYD model has been modified by introducing a nonlinear function to better reflect the non-constant loss of value of the powder. Initially, the loss of value accelerates, then stabilizes, and accelerates again towards the end of the powder’s useful life. The proposed depreciation model was used in a case study with two scenarios, which considered the varying residual economic values of recycled polyamide 12 (PA12) powder. The analysis shows that the method used to calculate powder reuse, whether in processing cycles or hours, can significantly impact on the overall material cost and, consequently, the final product cost.