Characterisation of Geometric Accuracy in Metal Fused Filament Fabricated Parts Using X-ray Computed Tomography

This work presents a methodology for quantifying geometric deviations in metal parts fabricated via Fused Filament Fabrication (FFF) using Ultrafuse 316L stainless steel filament. A blade-shaped geometry is selected as a representative case and analysed before and after sintering using high-resolution X-ray computed tomography (XCT). The XCT data are aligned to nominal and scaled geometries to assess deviations introduced during each manufacturing stage. In parallel, a thermo-mechanical sintering simulation is performed to predict shrinkage and deformation. Comparison between simulated results and XCT data reveals location-dependent discrepancies, with deformation at critical regions exceeding 2 mm and simulation errors ranging from 0.5 to 2 mm. The study highlights the limitations of standard shrinkage scaling and demonstrates the value of XCT-based characterisation in validating and improving predictive models for metal FFF. The proposed approach provides a foundation for model-informed design and process compensation strategies in sintering-based additive manufacturing.