Prototype assemblyThere needs to be enough prototyping to adequately cover and prove out development, the risk of not doing this can be counterproductive and costly. Prototyping cost must be established at the project start as a balance has to be struck between sufficient prototyping and the risk of addressing problems later in a project when parts may have been tooled and are in production.

Rapid prototypes are sometimes required at several stages during a project. This may vary from a single part for design validation or a small batch for product testing. Rapid prototyping can be used in many ways but is valuable in testing out a design to avert many problems before they get to manufacture. It is well known that the cost of correcting a problem escalates as a project evolves. After tooling, it is many times that of correction at the prototype stage which in turn is many times that of a design stage correction. We work proactively throughout the design process to help avoid such problems. In line with this, suppliers such as toolmakers are often provided with a rapid prototype to aid their design review and visualisation.

Rapid prototyping is used to help reduce development times. We use it to parallel up project activity that would not be possible by conventional means. It is also a powerful aid to design visibility for the designer, manufacturer and customer.

Rapid prototyping is now used for Direct Digital Manufacture (DDM) or "CAD to part" in situations where production volume is relatively low, design complexity relatively high, design change probability is high and start up investment is high. The benefits of this approach can include no machining or tooling cost, produces high integrity parts, no long lead times, inventory reduction, components supplied on demand and design can be changed during production with small costs.

This "tool-less" manufacture allows a significant change in design as it is design for use rather than conventional manufacture. Parts can also be designed and manufactured that are difficult or impossible by conventional means. A wide range of materials are available and is increasing. These include plastics, metals such as tool steel, stainless steel, cobalt chrome, low alloy steel, titanium, aluminium and precious metals such as gold, silver, platinum etc. Part cost to volume break even must be evaluated before embarking on this approach as there will be a point where some form of production tooling will be more cost effective and affect the design approach. DDM is ideal for industries such as automotive, jewellery, aerospace and biomedical implants, surgical fixtures and guides custom designed to the patient.