Rapid prototyping (a.k.a. Desktop Manufacturing, Solid Free-form Manufacturing or Solid Free-form Fabrication) consists of various manufacturing processes by which a solid physical model of a part is made directly from 3D computer-aided design (CAD) model data. This CAD data may be generated by 3D CAD Modelers, CT and MRI scan data or model data created by 3D digitizing systems.
To begin the Rapid Prototyping process, the 3-D data is sliced into thin (~.005 in.) cross-sectional planes by a computer. The cross-sections are sent from the computer to the rapid prototyping machine which builds the part layer-by layer. The first layer’s geometry is defined by the shape of the first cross-sectional plane generated by the computer. It is bonded to a platform or starting base and additional layers are bonded on top of the first, shaped according to their respective cross-sectional planes. This process is repeated until the prototype part is complete.
The resulting prototype provides a "conceptual model" for design visualization and review by the entire design team. It may be used by engineers to check form and fit and perform limited function tests. It can also be utilzed for soft tooling for prototypes and as a pattern for hard tooling.
The various existing rapid prototyping methods can be categorized by the material they use: photopolymer, thermoplastic, and adhesives. Photopolymer systems start with a liquid resin, which is then solidified by discriminating exposure to a specific wavelength of light. Thermoplastic systems begin with a solid material, which is then melted and fuses upon cooling. The adhesive systems use a binder to connect the primary construction material.