Rapid Prototyping
I was in the injection moulding world for six years, and it became glaringly obvious to me that I was on the wrong track," says Phil Bailey, now an engineer at Rapid Prototyping Inc. (Longmont, CO, USA). "It was taking us 8 to 12 weeks to make a part that someone using a stereolithography apparatus could produce in a couple of days."
With speed to market a constant concern among device manufacturers, it's no wonder that the advent of stereolithography (SL) and related rapid prototyping technologies has represented nothing short of a sea change for industry.
"People are interested in quickly getting into their hands something that is representative of what will ultimately be an injection-moulded or cast metal part," says Rob Bassil, technical director at DCA Design Consultants (Warwick, UK). "You can use SL parts to conduct market research, design the packaging, even, in the case of electronic equipment, get EMC approval," he adds. "And you can do all of this before beginning production."
Design accuracy is another advantage. In fact, says Ian Hollister of Kinneir Dufort Industrial Design (Bristol, UK), it may represent the greatest cost savings of all. "When you translate 3-D CAD data directly to a machine that replicates the shape, there is no room for error," says Hollister. "You're maintaining the same standard of translation throughout the entire process. Any error that does show up is going to be the result of the design itself, not one caused by a model maker's interpretation." Or, as Bailey puts it, "You eliminate the wag factor: the model maker who looks at a part and wonders, 'Now, does this really belong here?'"
The brave new world of rapid prototyping isn't devoid of limitations. Material selection has been a concern: The options are limited and SL resins, in particular, tend to be brittle and thermally unstable. In addition, working from direct data doesn't leave the traditional paper trail of drawings, so it's doubly important to check the data carefully. However, momentum is clearly on the side of rapid prototyping, and the technology is constantly being refined. "The materials used in stereolithography have improved dramatically since the process was launched," notes Bassil, and there is no reason to doubt that they will continue to do so. The surface finish of the models, Hollister adds, has also undergone a qualitative leap. "The layer thickness that was 0.2 mm is now down to less than 0.1 mm," he says. With adequate smoothing, he adds, it is even becoming feasible to develop models that are easily transferable to steel tooling, bypassing the tool maker entirely. In fact, many industry observers consider rapid tooling and rapid production to be, if not the final, certainly the next frontier of this rapidly evolving technology.
If you're interested in finding out more about this technology and how it might benefit your company, jump to the page containing brief descriptions of some of the industry's leading suppliers of rapid prototyping services and equipment.
