3D Printing for Cores

Binder Jetting is an additive manufacturing process that uses foundry sand as the base material. A print head selectively deposits a chemical binder onto thin layers of sand, progressively consolidating them to build the complete core, layer by layer, directly from a CAD file.
Unlike traditional Cold Box or Shell Moulding processes, no physical patterns or core boxes are required. The result is a core ready for casting, with a fine surface grain that is directly reflected in the quality of the final casting.

With 3D printing for cores, geometric complexity is no longer a production constraint but a design variable. It is possible to achieve:

• Complex monolithic cores that in traditional production would require multiple assembled elements, with the associated risks of misalignment and leakage
• Internal channels with variable cross-sections, tight curves and undercuts not achievable with conventional core boxes, eliminating the constraints linked to parting lines.
• Geometries optimised for the fluid dynamics of the liquid metal, reducing turbulence and gas inclusions
• Gating systems integrated directly into the core itself, with direct benefits for the metallurgical quality of the casting

• Functional prototype within a few days of sending the CAD file, with no wait for tooling.

• Fast design iterations: changing the geometry only requires updating the file.

• Reduced time-to-market for new components or variants.

• Lower costs for low volumes and pre-series

• On-demand core production for spare parts or components with low annual volumes.

The fine grain of ExOne sand produces internal casting surfaces with a roughness comparable to or better than conventional Cold Box processes.
3D printed cores follow the same coating, drying and quality control steps as traditional cores, with identical traceability and certification.

The technology is compatible with the entire range of cast irons produced by Fonderie Palmieri: Grey Iron, Ductile Iron (GJS), Compacted Graphite Iron, Austempered Ductile Iron (ADI), SiMo, Niresist and Nihard.

3D printing does not replace Cold Box production — optimal for large, consolidated series — but complements it, stepping in where geometric complexity, low volumes or fast development make traditional tooling uneconomical or insufficient. Fonderie Palmieri is able to assess the most efficient production route on a case-by-case basis.