RAPID PROTOTYPING IN ENGINEERING
The term rapid prototyping (RP) refers to a class of technologies that can automatically construct physical models from Computer-Aided Design (CAD) data. These "three dimensional printers" allow designers to quickly create tangible prototypes of their designs, rather than just two-dimensional pictures. Such models have numerous uses.
They make excellent visual aids for communicating ideas with co-workers or customers. In addition, prototypes can be used for design testing.
For example, an aerospace engineer might mount a model airfoil in a wind tunnel to measure lift and drag forces. Designers have always utilized prototypes; RP allows them to be made faster and less expensively.
At least six different rapid prototyping techniques are commercially available, each with unique strengths
. Because RP technologies are being increasingly used in non-prototyping applications, the techniques are
often collectively referred to as solid free-form fabrication, computer automated manufacturing,
or layered manufacturing. The latter term is particularly descriptive of the manufacturing process used by all commercial techniques
. A software package "slices" the CAD model into a number of thin (~0.1 mm) layers, which are then built up one a top another. Rapid prototyping is an "additive" process, combining layers of paper, wax, or plastic to create a solid object. In contrast, most machining processes (milling, drilling, grinding, etc.) are "subtractive" processes that remove material from a solid block. RP’s additive nature allows it to create objects with complicated internal features that cannot be manufactured by other means.