Control system of reverse side bead width by surface temperature monitoring of TIG weld

An experimental model of a reverse side bead width control system which employs a fiber-optic thermal sensor and a microcomputer has been developed. The system is worked by monitoring infrared radiation emitted from the surface of the workpiece. In this system, infrared rays emitted from the surface of the weld are picked up and transmitted via optical fiber to a photodiode which converts them into electrical signals. The welding current is controlled by an 8-bit microcomputer in accordance with fluctuations in these signals so as to ensure the optimum surface temperature is obtained for a high quality reverse side bead. (author)