Wire-droplet-substrate integrated model for heat transfer and deposition geometry prediction in GMAW-based wire arc additive manufacturing

Wire position can control the deposition geometry for same heat input during wire arc additive manufacturing process. However, because the integrated models are majorly from droplet to substrate and only tested for vertical wire position, the physical fields, droplet transfer, and deposition morphology with various wire position conditions are not fully understood. In this paper, a novel wire-droplet-substrate integrated model is developed to investigate the effects of wire position on heat transfer, droplet transfer, and deposition geometry. In order to consider various wire position conditions, the position angle between wire feed direction and scanning direction is defined as theta. The calculated droplet transfer and deposition geometry for various wire position angles agreed well with the corresponding experimental results. It is found that the wire-droplet-substrate integrated model can improve the accuracy of deposition geometry prediction by reducing the assumptions of droplet transfer and introducing the relationship between wire position angle and forces acted on the droplet and molten pool. Based on the stability of temperature and velocity fields within molten pool, it is found that sin theta is the dominant factor for the force along Z direction. The provided analyses of forces and heat and the predictions of deposition morphology are valuable for the design of process parameters.