Fuzzy classification of plasma reflection for keyhole sensing and control

Keyhole arc welding (KAW) can achieve deeper, narrower penetration than other arc welding processes. If KAW can be controlled in such a way as to minimize the heat input and the size of the weld pool while insuring full penetration, KAW could be an effective and affordable technology to improve the welding of thick materials. The key to developing such a controlled process is the development of a sensor that can detect the development of the keyhole. Preliminary studies have indicated that monitoring the plasma reflection could lead to a practical and accurate sensor for monitoring the keyhole development. Fuzzy logic provides a method for analysing this dynamic process in real time.