THE INFLUENCE OF MOLD TYPE ON SURFACE QUALITY PARAMETERS AND STRUCTURE IN THE PRODUCTION OF ARTISTIC CASTINGS USING PATTERNS OBTAINED BY ADDITIVE METHODS
DOI:
https://doi.org/10.32782/3041-2080/2026-7-13Keywords:
Investment casting, artistic casting, bronze, 3D printing, 3D modelingAbstract
Purpose. To investigate the influence of different molding materials on the surface quality and structural characteristics of bronze castings, and to evaluate the technological advantages of combining additive manufacturing (with investment casting for producing bronze artworks. Research Methods. Technologies Compared: The study investigated casting methods: Lost-PLA Plaster (IC), no-bake molds (NB), and sand-clay molds (SC). Master Model: A 3D-printed PLA master model was used. For NB and SC molds, a non-destructive model was used, while for IC, the PLA was removed during thermal burnout process (700 °C for one hour). Design Parameters: The model design incorporated specific casting parameters: draft angles of 2°, minimum wall thicknesses of 2 mm, and machining allowances of 1 mm. Analysis: The study analyzed surface roughness (Ra and Rz), grain size, porosity, and mold cooling rates. Results. Surface Quality: Lost-PLA Plaster Investment casting (IC) produced the best results with the lowest surface roughness (Ra = 2.8 μm, Rz = 12.5 μm), highest relief fidelity, absence of gas porosity, and minimal burn-on. No-bake (NB) molds showed intermediate quality, and sand-clay (SC) molds had the poorest indicators. Microstructure: Grain size analysis matched the surface quality trend. IC produced the finest microstructure (25.3 μm), followed by NB (25.5 μm) and SC (27.8 μm). Cooling Rates: The grain size directly correlated with the cooling rates of the molds: 1.2 °C/s for IC, 1.1 °C/s for NB, and 0.9 °C/s for SC.PLA Removal: The PLA model was successfully burned out without damaging the plaster shell, ensuring high geometric accuracy. Final Output: The combined IC and additive manufacturing process yielded high-quality bronze castings featuring 0.5% porosity, 95% equiaxed grains, and a controlled grain size of 25±2 μm. Scientific Novelty. The research establishes a direct correlation between specific cooling rates of different mold types (IC, NB, SC) and the resulting microstructural and surface properties of bronze castings. Furthermore, it validates specific operational parameters–such as a 300 °C burnout temperature and precise geometric design allowances–for successfully integrating 3D-printed PLA models into the investment casting process to achieve highly uniform, defect-free bronze artworks
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