SLA and SLS are very similar but for the material and the form it takes. Whereas SLA uses a liquid UV curable resin the SLS uses a powdered material. This is one of its major advantages since, theoretically, any powder that can be fused is capable of being transformed into a model and can be used as a true prototype component. Currently, the range of materials includes: -

• Nylon.
• Glass filled nylon.
• Polycarbonate.
• Wax.
• Metal. (Requires both a post sintering operation and copper infiltration cycle before the part can be used).
• Sand bonded with heat cured resin, making use of reverse engineering.

As with other RP systems the laser scans each slice of the component, in the case of SLS a fine powder is sintered. As each layer is sintered the platform lowers and a roller spreads a further layer of the material over the previous layer. During the build cycle any non-sintered powder helps to support the model avoiding the need for stilt supports as with the liquid resin system of the SLA. Removal of the prototype from the bath of powder requires a light brushing to remove any loosely attached material.