TWI Industrial Member Report Summary 935/2009
C Schuhler and G Melton
Vision-based systems are employed industrially for remote monitoring of arc welding processes in mechanised applications. The main difficulty encountered by operators is the high intensity of light emitted by the arc, which prevents good visibility of the metal transfer and weld pool and makes automated control of the process difficult. Clear images of the weld pool and surrounding area could be used for in-process quality monitoring and control, enabling manual or automated adjustment of torch position and welding parameters to maintain optimum welding conditions.
High speed videos are too expensive for the majority of industrial users. TWI, in cooperation with the University of Liverpool has developed a vision system for monitoring arc welding processes based on a low cost system comprising a complimentary metal oxide semiconductor (CMOS) camera and a laser diode array. The system uses a narrow bandpass filter that is tailored to the illumination source, and control of aperture and exposure settings to limit the amount of light reaching the camera sensor.
This report describes a programme of work carried out to evaluate the performance of the low cost vision system using tungsten inert gas (TIG) and metal active gas (MAG) arc processes.
- Further develop low cost vision systems for monitoring arc welding processes.
- Evaluate the performance of the vision system for viewing the weld pool in TIG welding.
- Evaluate the performance of the vision system for viewing the weld pool and metal transfer modes in MAG welding.
- Identify applications of the vision system which would lead to improved process control and understanding.