TWI Industrial Member Report Summary 411/1990
Naseer-Ahmed and W Lucas
A backface weld pool monitoring system had previously been developed for the control of the TIG welding operation. A video camera was used to monitor the weld pool and its size was controlled by means of pulsing the welding current. The controller employed a personal microcomputer for signal analysis and control of the welding parameters. The system was sensitive to HF which was required for automatic arc ignition.
A hard-wired controller was designed and constructed to overcome the problems caused by the HF arc starting. The controller was evaluated in a series of tests using plates of different thicknesses (1.0 to 3.2mm) and two casts of material, one of which was observed under fixed duration pulses to be 'difficult' to weld.