Complex and expensive mass production assembly lines have been in existence for a long time in, for instance, the car and consumer durable industries. High volume automatic metal cutting and forming machines have been developed to feed these lines with fasteners and other parts. All these have been dedicated systems; in some cases it is impracticable to adapt these production lines for a different product and even where this is possible they are inflexible, in the sense that it requires a relatively long time to reset the machines. Long runs were therefore necessary for economic production. The advent of the numerically controlled cutting and forming machines over the last 25 years followed by c. n. c. equipment with tool changing facilities, and more recently by groups of such machines loaded and unloaded automatically under computer control, called flexible manufacturing systems, have added a new dimension of flexibility in manufacture, which enables production of relatively small batches to be made economically. The next, much more difficult, step of constructing flexible automatic assembly systems is still in its infancy. The development of computers, and particularly of the microprocessor, have also revolutionized design and production control. The paper sets out the background to these changes, gives some account of their present state of development and the commercial advantages stemming from them through reduced cost and increased speed of response to market requirements.