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Selective Laser Sintering (SLS) for Rapid Prototyping

What is Selective Laser Sintering?

SLS is a process of fusing together layers of powder (eg. Nylon, Glass Filled Nylon) into a 3D model by a computer-directed CO2 heat laser. 3D CAD data of a new product or prototype component is sliced into layers, and the powder is sintered (melted) layer by layer. Additional powder is deposited on top of each solidified layer and again sintered. When the part is complete the build chamber is allowed to cool and the component removed.

The process is self-supporting and parts can therefore be nested together. The ‘selective’ nature of the laser process enables complex geometries to be achieved without compromising on functionality. Finished parts are surrounded by, and often contain, 'unsintered' powder - this loose powder is simply blasted away with an air gun and any post-processing work (ie. finishing or colouring) is then carried out.

SLS provides the highest level of functionality combined with speed that is currently available.

What machines do we build prototypes on?

Machines are produced by two major manufacturers; EOS GmbH based near Munich and 3D Systems, South Carolina, USA. Our suite of machinery boasts some of the world’s largest SLS machines - three EOS P730s, two EOS P380s and a 3D Systems HiQ 2500 Plus - thus enabling us to provide the optimal machine to meet our customers’ requirements.

Large parts are built in single pieces up to a build volume of 700x380x580mm on the P730s; the reduced need for joints and post-assembly dramatically increasing their functionality. The P380s allow parts to be built up to 620x340x340mm, and smaller parts with finer detail can be produced on the DTM.

Full specifications of these machines can be found in the SLS Machines section.

What materials can we build prototypes in?

There is a vast range of materials available for the production of prototypes, and we supply our components in Nylon, and Glass Filled Nylon.

Nylon is the most commonly used material in SLS, producing parts with good long term stability, strength and durability required for functional testing. Offering resistance to most chemicals, it is harmless to the environment, safe to use with foodstuff and is non-hygroscopic, thereby negating the requirement to seal the surface on components being used with liquids.

Glass Filled Nylon provides greater rigidity and is perfect when prototyping rigid parts intended for production in advanced engineered thermoplastics. The filler is glass bead and not fibre, hence the part predominantly increases in stiffness but not strength.

See our SLS Materials section for full material specifications.

How functional are SLS prototypes?

A simple test was carried out by parking an Audi A4 car on one of our SLS prototypes. The housing, 40mm high with a 6mm wall section, was to be cast in Steel in production. The result was no damage to the part (apart from some tyre discolouration!).

To demonstrate component functionality still further, we purchased a Smart Car with the intention of replicating or re-designing components, re-building them in SLS and testing them in everyday conditions. The success of this project has proved, beyond doubt, the capability, functionality and durability of our SLS prototypes.

You can view our Case Studies section for many examples of prototypes that have been tried and tested in true working environments.