In today's increasingly connected world, more and more data is being produced and processed. To meet these challenges, the OPTAVER research group is conducting research on an innovative manufacturing process for 3D waveguides. In this process, so-called conditioning lines are first printed onto a PMMA substrate by means of flexographic printing. Between those the waveguide is applied by aerosol-jet in a subsequent process. To achieve three-dimensionality, thermoforming is used. If the degree of forming is too high, the conditioning lines crack and become unusable, because waveguide material accumulates in these cracks. This leads to disadvantageous optical properties such as strong scattering and high attenuation. By inserting microstructures in the flexographic printing form at points where a high degree of forming is expected, material voids occur in the printing. These microstructures act as a predetermined breaking point, leaving the critical areas of the conditioning line in the forming process intact. This can significantly increase the 3D capability, as demonstrated in forming tests.