Mold SDM

Mold SDM (see Figure below) builds complex shaped wax molds for forming castable materials. These molds can be used for applications such as gelcasting of metal or ceramic slurries. Molds are fabricated using SDM with a sacrificial support material such as a water-soluble photopolymer occupying the mold cavity. Once a mold is complete, the support material is removed (e.g., by soaking in water) exposing the mold cavity into which the final part material is cast. The final part material can be any compatible castable material. Green ceramic parts are formed by gelcasting ceramic slurry into the mold and subsequently curing of the slurry. Then, the mold is removed by melting and the remaining green ceramic material is sintered to produce the final ceramic part.

While this process adds an additional step in the production of green ceramic parts, it does have significant advantages. First, since the mold itself is built using the SDM technique, high geometric complexity can be achieved. Also, the mold design is significantly simplified because the mold is sacrificed, which means no parting surfaces are necessary. Second, the molding approach produces monolithically cast parts, so there will be no layer boundaries or interlayer voids. Third, every surface of the mold is formed by direct machining or by replication of machined surface. In this way, the merits of machined surfaces are transferred to the final ceramic parts. This enables Mold SDM to efficiently achieve dimensional accuracy.