Testing and evaluation of products is carried out all the time during the process of design and manufacture. But did you know it also continues after the product is made? Products are evaluated by experts working for consumer magazines and TV programmes who tell us how well things work and whether they last. But they are also evaluated by those who buy or use the product ie YOU!

The evaluation of a product can look at factual information about it, for example, is it strong enough for the job, and it can also consider people's personal views, for example, do they like it. In a traditional 'design and make' process, evaluation takes place in a number of ways:

• at the drawing stage, ideas can be either rejected or taken forward
  
  
• by actually building part of the product, something called a mock up, which gives a better idea of whether the product will 'work'
  
  
• by building a test rig, which allows the suitability of different materials and structures to be tested, sometimes to destruction
  
  
• by market research carried out to find out the potential users' reactions to a developing design

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All of this information – some factual, some personal – is used by the designer to help improve design decisions.

When a designer is happy with a design solution, the idea is usually shown to the client in the form of a drawing or model which contains enough information for the client to decide if they like it or not. The feedback from the client will allow the design to be altered if necessary, leading to a final working prototype which may be fully tested to ensure that all the design criteria have been met.

During the production process, sample components/assemblies will also be tested to ensure that aspects of the production specification are being met and the appropriate quality assured. Depending on the product, the first items off a production line will often be tested to destruction to make sure that all national and international standards are being met before the product is released into the market place.

The final testing and evaluation will be carried out by the consumer in terms of his or her product satisfaction and by the client in terms of units sold and profit made.

From the above description it can be seen that focused thinking, testing and evaluation is a constant requirement in all the processes of designing and making.

The Dyson Contrarotator™ washing machine is a good example of how testing can not only ensure the quality of a product, but can also be used at the beginning of the design process as a way of coming up with new and imaginative solutions. The Dyson team began by testing different ways to get clothes clean. They didn't just accept or copy the design of existing washing machines but came up with their own ideas which eventually led to this innovative new product.

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The Dyson engineers used iterative development – they only ever make one change at a time. Then they test it before making another change. In this way you can see exactly which change has made an improvement. It is painstaking but necessary.

Engineers also have to test the reliability and durability of every component. Having proved the concept of two drums rotating in opposite directions, they built working prototypes and test rigs, in order to test their ideas about function and performance.

They also made models out of cardboard to analyse component assembly, and blue foam models, which helped develop the ergonomics of the machine. Rapid prototyping technology meant that engineers could construct accurate models of components in plastic or metal before they had to commit to the costly expenditure of tooling for manufacture.

They built a replica human finger to repeatedly test every button on the control panel 10,000 times.

They programmed the control panel 30,000 times.

They opened and shut the soap tray 10,000 times.

They opened and shut the double doors 30,000 times.

The Contrarotator™ took four years and a million working hours to develop and produce. Investing time, effort and money in research and development is crucial when developing any truly innovative product. The result is ownership of intellectual property patents which enables a company to stand out from its competitors.

A patent gives the patent owner the right to stop someone else making or selling the patented product or component in the country in which the patent is granted. Without a patent to protect an invention, anyone can take the same idea and use it in their
own products.