Engineering prototyping rubber and stereo lithography (SLA) uses the focused laser beam over a vat of liquid photo polymer resin. The laser accurately changes the liquid to a solid of the specified cross-section.

There are several resins available ranging from a rigid material that is excellent for master models to make moulds for cast copies through to more flexible and higher impact strength materials for better fit, function and use. SLA's remain the most cost effective method of prototyping most parts. Engineering prototyping rubber article Selective laser sintering (SLS) uses powder rather than liquid.

This time the heat of the laser fuses the particles of powder together again in small increments until the part is built up to size. This process offers the closest representation to an injection moulded part of any of the rapid prototyping processes. The SLS process uses material that imitate a nylon-like Polyamide, or a glass filled version (stronger nylon). As well there are versions of an elastomeric material, a polystyrene, SandForm, RapidSteel and Copper Polyamide. Laminated object manufacturing (LOM) uses the laser beam to cut the cross-sectional shape on a layer of material similar to butcher's paper. Again it repeats the process over and over, bonding each layer together, until the part is completed. This is a very effective method for parts with flat sections where any part warpage would be of critical concern. Because you are starting with a solid material, this is the most cost effective method for creating large models of parts with thick wall sections inside the engineering prototyping rubber.