Prototypes are an essential part of product development, both as a means of improving the design and to finalise a device before it is manufactured. Above all, they should be seen as design tools, to test out ideas and find ways of improving the product. Dyson famously made thousands of prototypes of his original cyclone vacuum cleaner before he considered it ready for production. That may be a bit excessive, but several prototypes should be considered the norm. So, what are your options?
1. Development prototypes
During the design phase, the prototypes need to be quick, simple and as inexpensive as possible to help you finalise the design.
An increasing number of design consultants are now installing their own ‘3D printers’ to help with this stage of the process. Typically based on ‘Fused Deposition Modelling’ or FDM, these printers produce relatively small parts (below 30cm cubed, usually) with a noticeably stepped surface out of engineering grade plastics like ABS.
Other processes, which will be available from prototyping bureaus, will include Sterolithography, which produces parts with a smooth surface but relatively poor strength; Selective Laser Sintering (SLS) which produces mechanically tough parts with a fine granular surface finish; and Polyjet technologies that can combine different materials and colours into one part. Finally, there is also the option of machining parts from solid. This may sound old fashioned, but new machining techniques have made it possible to create amazingly complex and detailed form very quickly. This, plus the use of ‘real’ materials, makes this option more viable than it might first appear. One of our projects used this approach to good effect. Take a look at the results here.
Finally, if you product involves sheet metal parts, you have no choice but to make your development prototypes using the same processes, as there is no rapid prototyping technology for sheet metal. That said, try and find a supplier who can work directly from 3D CAD and has laser cutting and digital bending facilities as this will reduce the complexity and time needed for prototype parts.
2. Product simulation
Once the design is finalised, you need to get prototypes made that look and operate as close as possible to the finished product.
One of the best options for this stage is the machined part option mentioned above. It provides excellent appearance qualities, replicates materials exactly, and can appear indistinguishable from the real thing.
Many 3D printing processes are not suitable for this type of prototype if they need to be durable, as a number of processes (Stereolithography and Polyjet, for example) produce parts which cannot withstand normal use. The most durable additive prototyping processes are SLS and FDM. Both often require considerable finishing to create the appearance of a finished product, however, so the costs might be quite high.
If your product is metal and small (less than 30cm cubed) you might want to consider one of the metal prototyping technologies like Direct Metal Laser Sintering (DMLS). This is a very expensive process, but produces extremely durable and accurate parts in a range of materials like aluminium and titanium.
If you need several prototypes for product demonstration, consider using vacuum casting. This process uses a 3D printed master part to make silicone moulds into which resin is drawn in a vacuum chamber. The results can look and work like real products, and they can be made in batches of up to twenty parts per mould. The materials can simulate normal plastics, and can be used for product demos and launches.
If you need more detailed information on product prototyping, or have a specific project you need to discuss, please contact us - we'll be happy to help point you in the right direction.