Dynamic simulation of short-circuiting transfer in GMAW based on the “mass-spring” model

In accordance to the characteristics of the arcing phase and the short-circuiting phase in the welding process, and in consideration of the variations of arc length, liquid bridge volume, and resistance, a metal transfer dynamic model and a welding circuit model have been developed, respectively. Based on the two models and some assumptions (such as the droplet-displacement equation during short-circuiting phase and the initial parameters of the arcing phase), an improved “mass-spring” model for describing the whole process of short-circuiting transfer (SCT) (includes arcing phase and short-circuiting phase) have been put forward. In addition, the model is proposed to predict the dynamic process with variation of welding parameters continuously, and the calculated results are compared with the experimental. The results demonstrate that the predicted short-circuiting frequency and average equivalent radius of contact droplets (just before short-circuiting) are in broad agreement with the experimental, and the equivalent radius of contact droplet of the two has an approximate uniform discrete distribution zone. Finally, an electrical signal is simulated, and comparative analysis is carried out.