An Intelligent Knowledge Based System for the Electro-Fusion Welding for PE Pipes [PE]

The Electro-Fusion welding of plastic pipes requires considerable knowledge and expertise in all areas associated with the technology, including the design of the fittings, design of the process parameters and the associated hardware, and joint preparation. On-site practice is also often difficult to control : environmental variables such as wind, ambient temperature, and contamination must be considered, and joint preparation such as pipe surface scraping is operator dependent. Furthermore, the application of new designs or larger sizes of fittings, new combinations of materials, and new process controls, can only be accepted after sufficient tests have been completed or experience has been gained. This paper describes an intelligent knowledge based system model for the Electro-Fusion welding of polyethylene pipes which allows the effect of many variables and parameters on the resultant joint quality to be investigated by computer.
Mathematical modelling is used to predict the thermal and deformation histories of the pipe and fitting during the welding process, which are then correlated with microstructural features. Expert knowledge is incorporated in the form of rules correlated with joints made under laboratory conditions. The model has been written into the form of a software program, and trials so far indicate potential benefits in terms of improved joint quality, more efficient jointing, improved guidance for good practice, and improved component design.