Development of a vision system for TIG welding - a work-in-progress study

The development of a Vision System for TIG Welding has the potential to help realize a real time process monitoring system for joining tasks which require automated welding. A key application of this technique is in the Nuclear Industry; where industrial components require several passes (layers of welding) to achieve robust joints. Through monitoring a welding process such as this in real time, material and time waste could be drastically reduced as faults could be instantly identified. A TIG welding arc is a very intense source of both light and heat, making the creation of a vision system for it challenging. Higher currents result in; brighter TIG welding arcs, higher energy input and deeper and wider weld pools. Nuclear industry applications require deep penetration welding but bright TIG welding arcs can overwhelm the intensity of an auxiliary illumination laser reducing the image clarity of an observing camera system. Thus, a balance between a wide weld bead with clear features applicable to deep penetration but without a brightness level which overwhelms that of the laser must be found. This paper is a Work-in-Progress study of a vision system for TIG welding using an automated TIG welding system and a camera with a laser illumination system. Welding was performed using a Miller Dynasty 350 at 100A with a 3B class laser used to illuminate the weld pool.