Biomedical resin reinforced with Cellulose Nanofibers (CNF) in VAT photopolymerization (VPP) Additive Manufacturing (AM): The effect of filler loading and process control parameters on Critical Quality Indicators (CQIs)

Abstract

Cellulose Nanofibers (CNF) are excellent reinforcement agents for biomedical resins in VPP 3D printing. However, the impact of process parameters on CQIs of VPP-fabricated geometries has not been investigated so far. Hence, the effect of CNF loading, Printing Angle (PA), and Layer Thickness (LT) on the porosity and dimensional accuracy of prismatic parts, is thoroughly explored with micro-Computed Tomography (μ-CT) techniques. The utilized L9 orthogonal array included nine experimental runs with five replicas. Each process parameter was ranked, and combined interactions were derived. The 1.0 wt% CNF loading was found to minimize both metrics. Moreover, LT of 50 μm and zero PA optimized the porosity, whereas LT of 100 μm and PA of 45 deg. maximized the dimensional accuracy. Quadratic Regression Models for porosity and dimensional accuracy were compiled and validated. This research induces a deep insight into the critical CQIs of VPP-3D printing for demanding biomedical applications.