NARROW GAP MIG WELDING CONTROL WITH IMAGE SENSOR.

This paper deals with a welding speed control method for the variation of the groove width by applying a new image processing method to detect the welding face and the wire extension for the automatic tracking control of the weld groove in the narrow gap MIG welding. In the welding system, the image obtained from ITV camera which monitors the welding arc through an optical filter is also used to watch the arc pattern on the remote TV monitor. The paper also describes a new narrow gap welding control system which has mainly the following features. (1) Automatic tracking of the weld groove and control of the welding speed simultaneously. (2) Control of the successive returning motion of the welding torch for the continuous multi-layer welding of the seam joint. (3) Remove operating of the welding machine and displaying of the welding condition. (4) Sequential control of the welding operation including automatic arc start-stop operation. The tests show that errors of tracking and wire extension are less than 0. 4 mm and 0. 7 mm respectively and the welding efficiency is improved considerably.