Electroforming of rapid prototyping mandrels for electro-discharge machining electrodes

The process of creating injection mould cavities, possible by a variety of methods, can be a lengthy one. The most common technique to obtain complex cavities is by utilising electro-discharge machining. This allows for the production of cavities that could not normally be produced by conventional machining methods. However, some electrodes for use in the electro-discharge machining process can themselves be difficult, and sometimes impossible to machine. By applying electroforming to the relatively young technology of rapid prototyping, complex electrodes can be produced in fairly reasonable timescales. This paper explains the work being conducted in this area by the authors, and the use of differing RP technologies in the production of these electroforms. It has been found that thin walled (≤1.5 mm) copper electroforms backed up with suitable filler materials are ideal for use as electro-discharge machining electrodes.