Paper Title
A Study of ARC Voltage Optimizing on Vertical-Welding Position Using Mahalanobis Distance Method by the Quality Prediction

A vertical-position welding process is the one of challenging positions because the gravity force would be affected to the metal transfer during the welding process which may be decreased in welding quality due to the welding fault. Recently, the methods that used to detect the welding fault have still been based on off-line method which would be wasted time and increased production cost because detecting of the welding fault could be done after the welding process finished. In order to solve the problem, this study proposed a new algorithm based on Mahalanobis Distance (MD) method for on-line monitoring system. Three different settings of arc voltage were chosen 23, 25 and 27 V to carry out the experiment to find out the optimal arc voltage. From the experiment results, it confirmed that the developed optimal algorithm could be achieved the highest quality of weld with the optimal arc voltage setting at 23 Vwhereas the welding quality was obtained 98.65% and 99.73%. Furthermore, the additional experiment has been verified that the developed algorithm using optimized arc voltage obtained good welding quality. Keywords- Vertical-position welding , Welding quality, On-line monitoring system, Mahalanobis distance, Welding fault.