Process planning is studied in detail at Plessey Military Communications, Ilford and the findings extended to a general description of process planning functions. Manual techniques are shown to cause a number of "bottleneck" problems and to limit long term manufacturing and company performance. The adoption of computer assisted techniques is shown to be the appropriate solution. Existing Computer Aided Process Planning (CAPP) systems and methodologies were examined and found to be significantly lacking through their limited applicability (via use of grouping), lack of realistic information handling facilities and relegation of the planner to a low-key coding role. These methodologies are shown to work through the capture and grouping of process planning logic. Many of the problems in current CAPP systems are attributed to their use of high-level definitions of process planning logic. A solution was sought through the development of a novel approach which allows the planner to construct a plan by selecting discrete pieces of manufacturing data. Each user builds his own database of logic by describing the sum of its manufacturing capabilities as possible manufacturing actions, requiring no in-built decisions logic. The system design is described in detail, including the constructive methodology for plan creation and additional facilities used to achieve comprehensive information control and application flexibility. The constructive approach is demonstrated as unrestrictive in application to companies with differing products, processes and working practises. System implementation in a hiqh-variety, rapid-change environment is described. Significant improvements in planner efficiency, planning speed and planner job satisfaction were observed. Long term manufacturing rationalisation and systems integration were predicted. The versatility of the approach allows the more strictly defined logic of variant and generative planning to be superimposed. This unified approach for all planning methods is considered to provide significant long-term benefits and improved planning efficiency over manual or existing methods.
|Date of Award||1984|