Recoater blade selection framework for AM processes utilizing powder

Powder recoating is a critical aspect of powder-based Additive Manufacturing (AM) techniques. The creation of a uniform powder layer is a top priority due to the dependence of the mechanical and microstructural properties of the specimen. Several recoaters, including blade and roller, are reported in the literature to distribute and level uniform powder layers to fulfill the layerwise AM approach. However, the literature fails to report a framework for selecting the optimal blade recoater. This study proposes a framework based on four parameters: deep-dipping approach, layer thickness, recoating time, and powder wastage. The authors tailored the deep-dipping approach from the Stereolithography (SLA) AM process and applied it to the powder-based AM processes. The framework is applied to seven-blade recoater combinations based on the blade count (one or two) and directionality (unidirectional or bidirectional). The analytical and experimental study resulted in the selection of the dual-blade bidirectional recoater. The selected recoater fulfilled the deep-dipping approach and achieved the required layer thickness (ta=tr) in minimum recoating time (T = Tmin) and powder wastage (Vw=2 V). Subsequently, the selected recoater is physically realized with a proof-of-concept (POC) followed by full-scale model installation in a self-developed laser-powder bed fusion (L-PBF) apparatus. The experimental study resulted in the production of a uniform sand layer and multiple specimens. The analysis revealed that the deviation in average specimen dimension along the build direction was < 3.23%, i.e., 51.41 mm, against the actual 49.8 mm. Thus, the results demonstrate the capability of the blade recoater selected via the proposed framework.