Conventional selection of welding conditions has a high dependence over the experience of the welder. Since the effect of process parameter on the penetration has not been grasped quantitatively when the target groove configuration and a welding position change, selection of welding conditions has to be performed each time. Moreover, there is the necessity of cutting and observing a cross-section in the penetration shape check to select optimal conditions, and it requires much time. Therefore, the demand to predicting and controlling penetration shape is increasing. In this research, the relation of an output waveform formation parameter, arc phenomena, and penetration shape is estimated for the controlling of the penetration shape change by a current pulse waveform. As a result, it becomes clear that a large factor in the penetration shape change is a Droplet Transfer Mode. Then, the possibility of penetration shape control is found. Moreover, the above-mentioned relation is incorporated into the conventional penetration shape simulation model and the validity of a simple heat source model which imitates change of the Droplet Transfer Mode as change of heat source configuration is evaluated.
