Selective laser sintering (SLS): how it works and what it can manufacture

Blog · CIM UPC

Selective laser sintering (SLS) is a polymer additive manufacturing technology in which a high-power laser melts thermoplastic powder particles layer by layer to obtain solid, functional parts, with no need for build supports. It stands out for its precision, versatility and mechanical strength, and is used to manufacture prototypes, short runs and, in some cases, end-use parts. Fundació Centre CIM (CIM UPC), an entity belonging to the Universitat Politècnica de Catalunya – BarcelonaTech, includes it among the technologies it makes available to industry.

How it works: powder, laser and no supports

The process starts from a bed of thermoplastic powder. A high-power laser melts the plastic particles layer by layer, following the geometry of the part. Because the technology requires no support structures, parts can be manufactured on top of one another within the same build volume, achieving geometries that would be very difficult to obtain with other processes.

Materials: from polyamide to polypropylene

Polyamide (PA) has traditionally been the reference material for selective laser sintering. The new technologies available at CIM UPC also make it possible to use more common plastics such as polypropylene (PP). The RICOH AM S5500P works with the range of materials approved by the manufacturer, which includes PP, PA6GB, PA11, PA12 and PA12GB. Glass or carbon fibre versions further extend the range of industrial applications.

Advantages of selective laser sintering

• Design flexibility: complex geometries can be manufactured with fewer restrictions than with other technologies.
• Excellent mechanical behaviour: robust, functional parts, suitable for validation or end use.
• High thermal and chemical resistance: parts withstand up to 80 °C and resist hydrocarbons, glycols and hot water.
• Competitive cost: ideal for functional prototyping and short-run production.
• Quality finishes: uniform surfaces, with no complex post-processing.

Common applications

Thanks to these properties, SLS is used to validate assemblies, to check fits, clips, mechanisms and real movements before moving on to final production; for parts with complex, lightweight geometries; for short runs or end-use parts in reinforced materials; and for components exposed to aggressive liquids. Parts can be joined using chemical bonding, which makes it possible to manufacture large-format parts.

CIM UPC’s equipment

The centre has the RICOH AM S5500P, a state-of-the-art SLS printer with an effective build volume of 550 x 550 x 500 mm, advanced temperature control, dual powder distribution and high reliability. Its large build volume allows multiple components to be manufactured at once, with fast, flexible and cost-effective production for sectors such as aerospace, automotive and medical.