Large Scale Additive Manufacturing (LSAM) based on plastic raw material is known for high material output and thus, increased productivity. For an improvement of part properties LSAM is combined with a laser process. Depending on the deposition direction, the laser beam needs to be repositioned to reach the space between two adjacent and consecutively printed strands. Therefore, an optomechanical design is required that allows variable orientation of the laser beam. It consists of a combination of an elliptical, tube-like mirror with an additional, rotatable flat mirror in one of its focal axes. The deflected laser beam hits the second focal axis where the extruder nozzle is located. Thus, > 75% of the nozzle circumference is covered during a laser beam treatment. Both mirrors are individually designed custom-made parts. Its functional verification lays the foundation for an improved additive manufacturing process, which aims to homogenize the component structures to improve the mechanical properties of 3D-printed components