Abstract :
Printed wiring was first introduced during World War II. The various processes developed for its production are briefly described. (Printed wiring is distinguished from printed circuits where components are deposited as part of the process.) The etched-foil wiring technique is studied in some detail and recent plating processes are discussed. Some base materials are examined, p.t.f.e. impregnated glass-fibre laminates having the best electrical properties of materials developed so far. Printed-wiring systems form the basis of automatic component-assembly techniques, which themselves require the development of suitable components and involve the standardization of certain parameters such as body size, axial design, lead diameter, and finishes for easy soldering. Several automatic soldering systems are in use. The development of microwave circuits is mentioned and special techniques for high-temperature operation of printed wiring up to 500°C are explained. The reliability of present-day printed wiring is examined. Trends towards future developments include progress in the microminiaturization field¿where true printed circuits are involved.
