Influence of the Offset Distance between Droplet and Molten Pool on the Molten Pool Morphology in TIG-assisted Droplet Deposition Manufacturing
To eliminate metallurgical defects such as porosity and cold lap in the formed parts fabricated by metal droplets deposition manufacturing technology,a novel droplet-based additive manufacturing method,called TIG-assisted droplet deposition manufacturing,for producing three-dimensional metal components is presented.A numerical model based on the computational fluid dynamics(CFD)method is developed to comparatively investigate the effect of the offset distance between the impacting point of droplet and the longitudinal plane of molten pool on the deposition morphology and the impact-induced molten pool behaviors.The numerical model is validated with corresponding experiments for three different lateral offset distances.The results indicated that as the lateral offset distance increases,the amount of liquid metal that contacts with the cooler substrate or the asymmetric pre-solidified bead increased,which leads to exposing more contact area for heat dissipation.Consequently,the symmetry of solidification front morphologies will be broken,an obvious increase of the asymmetry in the thermal-flow fields within the droplet impact-induced molten pool and deposition geometry was observed.The results of this paper can provide theoretical support and basis for the process parameters'controlling and adjusting of TIG-assisted droplet deposition manufacturing.
additive manufacturingTIG welding arcdroplet depositionmolten pool behaviordeposition morphology
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