Thermal process simulation of droplet based metal printing with aluminium

Droplet based additive manufacturing is a branch of novel processes to build full dense metal parts by adding material droplet by droplet on a build platform. As each droplet solidifies individually upon contact, the quality of bonding to the existing material is determined by the adjacent surface temperatures and the temperature of the arriving droplet. To design a manufacturing process that ensures good bonds between all droplets, it is necessary to understand the relations between process parameters, the part’s geometry and thermal conditions for each arriving droplet. This paper presents a thermal simulation model that is based on Flow 3D software. By adding a user routine to the solver, it is possible to simulate the building process of a part consisting of several thousand droplets with an acceptable effort. This simulation is used to study the effect of production parameters (substrate temperature, droplet temperature and deposition frequency) as well as the parts geometry (layer size and height) on the resultant temperature field. The model was successfully validated with experimental data and can deliver valuable information during further development of this additive manufacturing process.