Evaluation of inserts for modular thermoplastic injection moulds produced by spin casting

Concurrent engineering enables a company to speed up its time to market: rapid prototyping forms a part of this approach. The term rapid tooling (RT) refers to the rapid creation of tools in much the same way as RP means the rapid creation of models. It is a method that offers both designers and manufacturers attractive advantages in the form of time compression and cost reduction. In an era of automated manufacturing the prototype can be produced layer by layer directly from a 3D CAD model using rapid prototyping (RP) techniques [Rapid prototyping and manufacturing, fundamental of stereolithography, SME, Dearborn, MI, 1992; Layer Manufacturing a Challenge of the Future, Tapir Publisher, Trondheim, Norway, 1992]. The drawback is that only a limited number of RP technologies cater for metal parts and taking the top three positions of vendors into account (Stratasys, 3D Systems, Sanders), their systems have no access to metal prototypes [Rapid prototyping, state of the industry report 1998, SME, Dearborn, MI, 1999]. Several RT techniques can be employed to save time in the manufacturing of plastic injection moulds: thermal spraying; quick casting, electroplating, direct metal sintering. These techniques have been subject to intensive study for a number of years and their extensive commercial potential makes them attractive propositions. Major advances in technology makes spin casting a fully proven tool for manufacturing and prototyping functional components. This paper describes the employment of spin casting for the construction of mould inserts in standard, commercial-grade pressure die casting zinc.