This process is based on the principle of curing (hardening) a photopolymer into a specific shape. A vat is filled with a photocurable liquid acrylate polymer.Then a laser generating ultraviolate beam is used to harden one layer on a moving platform in the vat. After many layers, the prototype is formed. The name stereolithography was name for its similarity to lithography where the image is printed on a flat surface where it is ink receptive and the blank areas are ink repellant. The difference between the two is the rapid protoyping process creates in 3-D.

This process is based on the principle of sintering (heating without melting to produce a coherent mass). Metallic or non-metallic powders are used with a laser guided by a CAD program. Some materials being used are PVC, nylon, polyester, and polystyrene.

Other Types:(Cost: $50,000-$500,000)

This process binds the powder by ink-jet printing of an inorganic binder matter (ex. colloidal silicon). Some of the powders used are aluminum oxide, silicode carbide, silica, and zirconia.

The process utilizes streams of material (ex. plastic,ceramic, metals, or wax) ejected using an ink-jet mechanism through a small orifice at a surface. It uses a piezoelectric pump at 50 micrometers/ 10,000 per second, and a 3 axis robot.

This process is similar to stereolithography except it uses two lasers. It uses one laser for the x-y plane and another laser for the x-z plane.

This system is also similar to stereolithography except it uses a visible light argon-ion laser, and the part is built on a stationary platform.

This particular system utilizes a thermoplastic filament similar to wire, which is then fed through a heated extruded head.

In this system, the part is formed in multiple layers. A photopolymer liquid in each layer is covered with a photomask and cured for several seconds by a strong ultraviolet lamp. The exposed liquid polymer is then removed and the voids are filled with wax to support the next layer.

This method is based on the principle of layers of sheet (metal foil, paper, plastic bonded together in a stack). A laser cuts each sheet one layer at a time. The process removes material rather than consolidating it as compared with the other processes. The sheet thickness ranges from 0.05mm-0.12mm (0.002 in.-0.005 in.).(Sources: Computer Integrated Manufacturing Systems)