Process Control and Automation Developments in Welding

With an international shortage of skilled welders and concerns about exposure of personnel to welding hazards it is appropriate to consider how joining processes can be simplified and automated. The paper reviews the process control techniques which have been applied to enhance the productivity and quality of welded joints. It seeks to explain the influence of power source design and computer control on these developments. In particular it will address the real time control of short arc GMAW and explain how by modulation of the transient electrical properties and high speed wire feed oscillation process performance has enhanced in several recent variants of controlled short circuit transfer. An attempt is also made to put these developments in context when compared to conventional GMAW, and to explain the potential benefits and to classify them according to recent IIW metal transfer scheme. The process control potential of other developments; such as tandem and hybrid laser GMAW with also be described. The trends in welding automation are reviewed and in particular the techniques for off line and rapid programming of welding robots and on line monitoring and control techniques will be reviewed. Finally the continued importance of fundamental studies into process control and automation is stressed.