Fig. 1 shows a prototype of a new hand-held product being evaluated. Analyse how a manufacturer should test this prototype before committing the design to p...

Before production, testing must be systematic and linked to the specification. A prototype that merely appears satisfactory has not necessarily been proved safe, usable, durable or manufacturable.

1. Function: test every stated requirement in the specification and measure the result against its criterion, rather than relying on personal judgement. [2]
2. User testing: intended users should complete realistic tasks without assistance. Observe where they hesitate, misunderstand controls or make errors, because the design team already knows how the product is supposed to work. [2]
3. Durability: carry out relevant drop tests, repeated operation of controls and exposure to expected conditions of use. Faults that arise after months of use are much more costly once products have been sold. [2]
4. Manufacture: confirm that components can be made and assembled at production tolerances and at an acceptable cost. [1]
5. Safety and standards: complete the required safety and standards testing, since a product cannot legally be sold without relevant approval. [1]

A well-founded decision to proceed should be made only when the prototype meets the specification, users can operate it effectively, and production can deliver it consistently.