The integration of computers with the manufacturing shop floor will reduce direct operating costs and ultimately create the ″automatic factory″ . The key to this integration will be direct numerical control (DNC) - automatically transmitting manufacturing data to the shop floor to control manufacturing work. This article describes a DNC system that will permit gradual transition to a computerized manufacturing facility. In the proposed system the required flexibility is achieved by using the minicomputer in the CNC units as terminal, computer, and controller. To gain the terminal operation, it was necessary to replace the perforated-tape reader with a flexible-disk read-and-write unit and to add an alphanumeric keyboard and an RS-232-C communication interface with appropriate software for a two-way conversion with the DNC computer. This permitted the CNC unit (after keying in the job number on the alphanumeric keyboard) to retrieve machining data from the DNC computer, record it on the floppy disk, shut itself off from the DNC system, and then operate as a CNC stand-alone controller. To highlight the difference from real-time DNC systems in use, this new concept was called the ″non-real-time DNC system″ , and later more aptly described as the distributed data processing/direct numerical control (DDP/DNC) system. It could achieve all the goals in the guidelines because the DNC minicomputer serving the new CNC units would be ideal at least 80% of the day, and it could easily support additional systems, such as production control and scheduling, cost analysis in real time, N/C monitoring and data processing of N/C programs.
