Application of KBE to NC Programming of Fastened Assemblies.

Abstract

The introduction of a Computer Numerical Control (CNC) wing fastening facility in BAE SYSTEMS Airbus UK for the Airbus A340-600 wing led to substantial efforts to reduce Numerical Control (NC) programming time. Since specific values had to be determined for each of 110,000 fastener locations, manual calculations and input had to be eliminated. The decision was made to generate an intelligent CAD model, with “attributes” attached to each fastener location. These attributes would hold three-dimensional information regarding the cross-sectional dimensions of the assembled components at each fastener location, calculated using Knowledge Based Engineering (KBE) software, prior to the NC programming process. The NC software was then configured to read this as background data to programming instructions and to generate output accordingly. This process reduced data preparation by 90% giving significant savings in NC programming time compared to existing methods, with a marked improvement in machine cycle time and quality of first article components. This paper will explain the development of a knowledge-based NC programming system, and will identify the need for improvement, the existing methods of data preparation, the development of an efficient system and the inherent benefits associated with its implementation.