The PCB prototype is a key role in the design and creation of printed circuit boards. The design of a PCB is often determined by a vague set of requirements. It is created to define the functionality required for mechanical and electrical products. The prototype is the proving ground for these needs.
The designer incorporates all of the functionality that can fit into a board. Sometimes the requirements are extensive and the board may be both large and very complex. Many things are required for the design to make it to the prototype stage. Functionality and reliability are at the forefront. The number of layers required depends on the complexity of the requirements. Some boards are only two layers, but in detailed applications they may reach over 32-layers. Size is also crucial. The board must fit into the system it is being designed for. The tolerances used in most PCB design are to the thousandths of an inch, making each layer and each copper trace critical. They are designed under extremely tight tolerances and this integrity must be checked and re-checked for accuracy. Signals must be clean and voltage must match the application. Components added to the surface must also meet the tight tolerances. The first board that is created is referred to as the prototype. This can range in quantity from one to hundreds depending on the level of testing done.
The PCB prototype undergoes extreme scrutiny. Everything has to be checked during the manufacturing process. All the traces and leads are re-measured to ensure thickness before the board is pressed. The holes and vias are drilled using very sophisticated equipment and they have to be pre programmed for each board. When the components are added to the surface, again the electrical signals are tested and the tolerances are checked. Once manufacturing has created the board to the specifications, the prototype is then tested and retested. Every requirement of the board has to be scrutinized for effectiveness and reliability. The board is tested independently to ensure functionality before being integrated into the environment it is designed for. Each step is recorded and documented. Any failures must be addressed completely and in some cases a new prototype with modifications will need to be built. The prototype remains under close scrutiny until it is performing as required.