The term "rapid prototyping" is a relatively new expression for the generation of three-dimensional models manufactured without the need for machining or tooling.

• Production of models by machining has a number of limitations:-

Material removed during forming is difficult to reclaim.

Machining, in the form of drilling, turning, milling, spark erosion etc., is limited by the shapes it can produce.

In the event of design change conventional tooling such as patterns, core boxes, dies, jigs etc., become expensive to alter and, in many cases, may require complete re-manufacture.

• Rapid prototyping differs by:-

Adding material layer by layer until the desired shape is achieved, immediately reducing or avoiding the loss of material.

Cutting out the conventional draftsperson, patternmaker and in some situations even the moulder, the system goes a long way towards reducing time taken and cost and improving accuracy.