Additive manufacturing simulation

Additive manufacturing involves building an object from a material that can be deposited locally or consolidated selectively along the part's geometric path. In other words, the material is brought from a malleable state, which is easy to process, to a consolidated state, to form a rigid structure. Additive manufacturing technologies are numerous, and can be grouped according to three construction principles: material deposition, selective consolidation, and powder binder spraying, which combines the two previous principles. To achieve these constructions, the processes involve energy and mass transfer.

Among these processes, laser technology (CO ₂ , YAG) is ideally suited to the selective consolidation of materials. Thermal energy is used to transform the base material by fusion, diffusion (sintering) or chemical reaction.

Material can be deposited in the form of drops, filaments or powder, which must be brought to a liquid or viscous state before consolidation on the object.

The manufactured object appears voluminous compared to the volume of material consolidated at each stage of the process. From the micrometer to the centimeter scale, the construction of the edifice takes place, as it rebalances and deforms at every moment.

Simulation not only helps reduce the number of tests required to produce a part in compliance with specifications, but also provides a better understanding of the relationships between operating parameters, material properties and the manufacturing state of the final part. It is therefore in order to determine the best manufacturing conditions and predict their microstructural and mechanical consequences that it is in the interest of industry to develop simulation.

Simulation can also help manufacturers to optimize the design of their additive manufacturing process, by studying the consequences of a choice of materials, a change in geometry, or a heating or cooling system.

It also makes it possible to envisage several scenarios for the additive construction of parts on different consolidation paths, and to compare their consequences. Indeed, even if the part design is fixed by the design office before manufacture, the possible deposit paths and filling patterns are virtually infinite. This has a direct impact on the adhesion of the deposited layers, and therefore on porosity, the mechanical anisotropy of the part, residual deformations and stresses, and ultimately on the durability of the part.

Process simulation first involves assessing the energy, mass and momentum transfers required by the process to effect the change of material state. A model must be chosen to describe...