Engineering

Once the design is complete, a prototype or preliminary working model is generally built. The primary function of the prototype is to demonstrate and test the operation of the device. For this reason, its cosmetics are typically of little concern, as they will likely change by the time the device reaches the market.

The prototype stage is where the device undergoes extensive testing to reveal any bugs or problems with the design. Especially with complex systems, it is often difficult to predict (on paper) where problems with the design may occur. If one aspect of the system happens to fail too quickly or does not function at all, it is closely analyzed and that sub-system is redesigned and retested (both on its own and within the complete system). This process is repeated until the entire system satisfies the design requirements.

Once the prototype is in complete working order and the engineers are satisfied with its operation, the device goes into the production stage. Here, details such as appearance, ease of use, availability of materials, and safety are given attention and generally result in additional final design changes.