Patent ID: 7533713

Claim:
A process for producing a casting mold for metallic foundry or for precision casting of fine metal parts, wherein the casting mold, or at least a part thereof, is produced by a generative rapid prototyping process, said process comprising: a) forming a layer of a mixture of ceramic coarse particles and sinterable ceramic fine particles, wherein the average particle diameter of the coarse particles is above 10 μm, the average particle diameter of the ceramic fine particles is below 5 μm, and the average particle diameter of the ceramic coarse particles is at least 10 fold of the average particle diameter of the ceramic fine particles, b) melting or sintering the ceramic fine particle under the influence of intensive radiation without substantially melting the ceramic coarse particles such that the fine particles form bridges binding the coarse particles, and c) repeating steps a) and b) to form successive layers until a casting mold, or at least a part thereof, comprised of a porous ceramic in the sintered state is formed, wherein the thermal coefficient of expansion of the thus produced ceramic casting mold or part is above approximately 8.5*10 −6 K −1 .