Frequently Asked Questions

My project will need hundreds of prototypes. How do I make them economically?

As quantities rise, the options become more limited and factors such as the geometry and size play a greater role. For example, a small complex part can be laser sintered in significant volumes (100's) at a competitive price. As complexity reduces and size increases, both PU moulding and tooling have a greater role to play. The greater the quantity, the more competitive development tooling will be over PU moulding.

So, assuming the part is small and an SLS finish is acceptable (i.e. we are more interested in function than aesthetics), SLS is the place to start. After that there are two PU options; the first is Vacuum Casting into silicone tools, the second is Reaction Injection Moulding (RIM) into composite (hard) tools.

Vacuum Casting and Reaction Injection Moulding

As a general guide, RIM is more applicable to larger, heavier sectioned parts, whilst Vacuum Casting is more applicable to complex, thin walled items. To master the complexity, Vacuum Casting utilises a flexible silicone for the tool. This allows the tool to be deformed and the part released, thus avoiding compressible cores and side actions, which would be used in a 'hard' tool.Prototype Tooling

The limitations are that the silicone progressively hardens, leading to a tool 'life' of around 20 - 30 shots. 200 parts would therefore require 8 - 10 tools depending on complexity. However these can run in parallel and the parts can be part shipped from about 2 weeks onwards.

Development Tooling from 20 parts

Development tooling can be economically viable from as low as 20 - 50 parts depending on the part in question, and is applicable into the 1000's. Part cost is very low compared to the alternatives, although the tooling is more expensive. Unlike Vacuum Casting, parts cannot be shipped progressively and only start to become available after T1 (first trial). This remains the only way to produce production intent material parts.

In summary, the route chosen needs to be decided upon based on size, complexity, aesthetics, material requirements and time, and the economics become a consequence!

To explore prototype tooling in more detail, take a look at our dedicated Injection Moulding and Tooling section. 

 

Related Processes

Selective Laser Sintering (SLS)

Selective Laser Sintering (SLS) is the second most commonly used process after Stereolithography (SLA). SLS parts can be produced with high functionality in very short lead times.

more info

Injection Moulding

Produces production intent material properties. Injection Moulding is used for development as well as production parts.

more info

Vacuum Casting

Ideal for producing small quantities of plastic and flexible rubber parts, especially if aesthetics are important.

more info

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