How are the models made?

The RPG models are manufactured using a process called selective laser sintering, or SLS. This is a process that is used in motorsport, including Formula 1, aerospace, architectural modelling and medical applications. It entails the fusing together of layers of very fine powder (in our case, nylon) into a 3D model by a computer-directed CO2 heat laser. The model is designed using computer-aided design (CAD) and the resultant 3D CAD data is then sliced into layers, which in our case are 0.12mm thick and the powder is sintered (melted) layer by layer. Additional powder is deposited on top of each solidified layer and again sintered. When the models are complete the chamber is allowed to cool and the components removed.

The process is self-supporting, which means the models can be positioned anywhere in space within the confines of the build chamber, hence models can be ‘nested’ together to allow a number to be made in the same run, thus making the process more economical. The ‘selective’ nature of the laser process enables complex geometries and details to be achieved with no more difficulty than simple shapes. Finished parts are surrounded by, and often contain, 'unsintered' powder – this loose powder is simply blasted away with an air jet and the model is then ready for inspection.

The SLS process provides the highest level of detail, combined with speed and reasonable price that is currently available.

What are the benefits?

• No tooling is required as the models are made directly from the CAD data, so there is no deterioration of quality with large production numbers as is often the case with moulded or cast models.
• There is a great degree of flexibility in the design process as the manufacturing method allows a single piece manufacture of a model that would need to be assembled if the parts were moulded or cast.
• Making variations of the basic model only requires a small amount of CAD time rather than creating new tooling, hence it becomes an economic option.
• Creating different scales of an existing model only requires a ‘scale factor’ to be applied to the CAD design data and not an expensive new mould tool.