Computer/interactive cleanup of non-gridded PWB's after automatic routing

Sandia Laboratories is responsible for the design of a variety of printed wiring boards (PWB's) which often have severe size and shape constraints as well as extremely high reliability specifications. This sometimes necessitates meticulous component placement and interconnect positioning; consequently, many of the PWB's are not laid out on a grid. For PWB's which are used in space satellites there is another important constraint: there must not be any acute angle in the metal pattern. Indeed, only recently, and with some scepticism, have right angles in interconnects been tolerated. This angle constraint poses special problems in the cleanup of interconnects in the neighborhood of a land, as the interconnect must enter land radically

Computer aids have been developed to ease the task of the designer and one large program written at Sandia, DAVINCI, utilizes interactive graphics. DAVINCI has evolved from a PWB editor to become a design tool with extensive interactive capability for handling component placement, interconnection definition and other PWB design activities. The main DAVINCI program resides on a CDC 6600 but a DEC PDP-9 serves as an interface between a Vector General CRT and the large computer. The interactive graphics activity occurs in a time share environment. And, although graphics jobs have top priority, there is a strong incentive, if not a requirement, to keep the size of the program in core at any one time to a minimum.