Abstract
<jats:p>Wire-based directed energy deposition (DED) additive manufacturing (AM) uses an intense energy source, such as an electric arc, laser, and electron beam, to melt metal wire feedstock and deposit a structural part layer by layer. This emerging manufacturing process is advantageous thanks to its large-scale deposition capacity, high efficiency of material and energy usage, and wide applicability to different industrial applications. However, research is still needed to enhance the process productivity and part quality. Wire preheating is a feasible method to significantly enhance deposition rate. It can also help reduce heat input of the main energy source, inhibit pore formation and refine grains, thereby enhancing mechanical properties of the deposited part. Induction heating (IH) is a highly controllable non-contact heating method suited for rapidly and precisely preheating the wire feedstock to a target temperature. In addition, compared with conventional weld wire preheating methods such as resistance heating and bypass heating, IH avoids magnetic blow and is applicable to most metals with flexible setup. However, IH-based preheating of moving wire feedstock is complicated and underexplored for AM applications. In this study, to understand the complex electromagnetic heating mechanism, a multiphysics finite element model of coupled electromagnetic and thermal fields is developed based on the formulation in Eulerian frame, which improves the computational efficiency by 80.9 % compared to the model in Lagrangian frame. Furthermore, in the case of feedstock passing through a stationary magnetic field at a constant wire feed speed, a more efficient steady-state approach is proposed with 98.9 % computational time saving than the transient model. The temperature predictions by the models were validated by thermocouple measurement in an experiment. A range of coil geometries and setups were evaluated using the developed efficient model, revealing the coil effects on the wire preheating temperature and energy consumption.</jats:p>