Rapid Prototyping

One of the most powerful advantages associated with CAD modeling is the ability to create physical 3D prototypes of the design using the actual CAD model data itself. These prototypes can be used to evaluate the shape of the product for aesthetics or ergonomics, testing and verifying component performance, and to ensure part fits and function before committing to production tooling, such as injection molds and die casting dies.

The prototypes can be produced quickly and inexpensively, usually within a few days and for a few hundred dollars, more or less depending on the size of the parts and the number needed. And because they are made directly from the CAD models themselves, any design mistakes made, such as interference between parts or omitted features, can be corrected in the CAD model. Then a new set of prototypes can be produced to verify the corrections.

It is not uncommon to use several prototype "builds" during the development process to evaluate the design at different stages. For example, non-functional industrial design models may be used for trade show demonstrations or marketing research to define shapes and colors. Later, functional models can provide test data to verify mechanical design. Finally, the CAD files can be released for injection molding or die casting with only small adjustments required for overall part qualification.

In general, prototypes are made in either plastic or metal, with plastic being used much more often due to lower cost and the comparable similarities with injection molded parts. The plastics used are either liquid photopolymer, powdered thermoplastics, or extruded thermoplastic filament depending on the process. The metals used are very fine metal powders, and include copper alloys, stainless steels and others. For die cast part verification, either process can be used to verify dimensional accuracy, and plating is available to give some plastics the look and feel of metal.

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