Rapid Tooling Techniques

Nickel Ceramic Composite

Instead of building the mold through a powder metal process, Cemcom builds it atom by atom through nickel electroforming.

The process begins with an SL model. This "positive" is suggestive of the molded part, but not a perfect copy. Instead, it has an extra half-inch or so of thickness between the core and cavity surfaces—as if the molding press had not quite closed.

The resulting rigidity lets core and cavity shells of electroformed nickel grow simultaneously on the model's opposite faces. The shells—each only about 0.1 inch thick when finished—are then backed using a thermally conductive ceramic, which fills in the gap between shell and mold frame. Thus the two nickel shells become two halves of a finished injection mold.

Surface finish is one area where this process shines with a resolution almost on the molecular level. The molds have precisely the same surface finish as the SL master.

Another strength of the process is its ability to produce molds larger than 6" X 6" X 6", and do so economically. While the time to machine a mold grows in proportion to mold volume, the time to electroform does not. As a result, electroforming's cost and leadtime advantage should grow as the size of the mold grows.

The process is still under development and currently isn't consistent enough yet for general use. Tool life ranging from 10,000 to 50,000 parts is a reasonable expectation for the electroforming process.