With the introduction of rapid prototyping processes nearly twenty years ago, it became possible to create patterns for investment casting directly without first creating tooling.  The initial inability of rapid prototyping processes to meet accuracy and surface finish requirements for production castings limited their use to prototype castings.  Over the past ten years, however, the quality of RP investment casting patterns, now referred to as direct patterns, has improved dramatically.  Stereolithography QuickCast™ patterns, the most common direct pattern process, now rival molded wax patterns in accuracy, surface finish, and in casting yields.  As a result, QuickCast patterns are increasingly being used for production castings, not just prototype. It is estimated that in 2006, more than 50,000 castings were created from QuickCast patterns and that more than 30% of those were for production castings.

 QuickCast patterns can be created quickly and without tooling.  Consequently, for many applications, they allow investment casting to compete effectively with machining on low volume projects, often providing a significant savings in both the time and cost of obtaining components.

This study reviews several case histories and presents guidelines for determining when investment casting using QuickCast patterns provides advantages over machining for low volume projects.