Study of Thermophysical and Mechanical Properties of a Corrosion-Resistant Steel-Based Feedstock and Prediction of Warpage in FFF-Manufactured Green Parts

This paper presents the results of an experimental study of the thermophysical and mechanical properties of a feedstock based on 09Kh16N4B steel powder (an analogue of AISI 630) intended for the manufacture of green parts by fused filament fabrication (FFF). The comprehensively determined thermophysical and mechanical properties of the feedstock under study were used as input data for thermomechanical simulation and for experimental verification of the warpage of FFF-manufactured green parts. The study is motivated by the need to predict and minimize warpage, one of the most critical defects arising in FFF 3D printing. A feedstock containing 52 vol.% metal powder and 48 vol.% binder was found to have the best processing characteristics. The key thermophysical and mechanical properties of the material required for simulating the printing process were determined experimentally. The Young’s modulus was 6500 ± 100 MPa, which is 1.8 times higher than that of pure polyoxymethylene. The data obtained were used as input for simulating the FFF process in Digimat-AM 2023.1 (Hexagon AB), the additive manufacturing simulation module of the Digimat software suite. The stress–strain state of the green parts was simulated during their layer-by-layer formation and subsequent cooling. Comparison of the numerical simulation results with experimental data digitized by 3D scanning demonstrated high prediction accuracy: the root-mean-square (RMS) deviation was 0.138 mm, and the discrepancy between the calculated and experimental corner displacements of the sample did not exceed 5%. The results confirm the validity of the model and justify the use of Digimat-AM for predicting warpage and optimizing FFF process parameters, which makes it possible to reduce the amount of experimental work, lower the probability of producing defective green parts, and reduce production costs.