Production of inorganic hollow cores using sacrificial ice cores

The production of hollow cores using 3D sand printing is state-of-the-art. Hollow cores are advantageous in decoring, gas permeability and material consumption. The methodology for producing hollow cores, as in 3D sand printing, is not transferable to core shooting. However, using sacrificial ice cores (SaIC) as a tool to produce hollow cores in a core shooting process enable complex hollow structures, as in 3D sand printing. Recently there has been an effort towards more environmentally friendly production. In this regard, water glass binders are in the focus of the metal casting industry and research institutions. This work presents a new method for producing water glass-bonded hollow cores using SaIC in a core shooting process. The manufacturing principle is detailed using a bending test bar and a near-series prototype core. The bending strength of the hollow bending test bars reaches up to 300 N/cm2. Due to the hollow structure, the decoring behaviour is significantly improved compared to solid cores.