High-Throughput Micromechanical Testing Enabled by Optimized Direct Laser Writing

Direct laser writing by two-photon lithography enables the manufacturing of tailored 3D objects, commonly referred to as 3D-printing, with submicrometer precision. Thereby, new approaches are enabled for miniaturized optical and mechanical devices, where basic material properties act as design guideline and initial input for finite element simulation-driven device design. These mechanical properties are accessible through micromechanical testing and suitably adapted miniaturized specimens. With direct laser writing, a micromechanical specimen geometry can be readily manufactured without additional postprocessing, enabling the possibility of repetitive sample production and further high-throughput testing. Widely overhanging features, as in common bending beam or tension specimens, easily cause floating layers as writing artifacts and thereby undefined geometries. Within this work, an approach to overcome this issue is presented. By introducing a slight taper within the geometry at initially printed layers, a reliable sample geometry is achievable without changing the overall mechanical behavior. As showcase geometries, miniaturized notched cantilever and advanced push-to-pull devices incorporating a notched tension specimen are detailed. Mechanical testing is conducted in situ and ex situ, and the mechanical influence from introducing a taper to a straight geometry is assessed via a finite element modeling. Thereby, a comprehensive approach for high-throughput micromechanical testing is established.

Automated summary

Direct laser writing by two-photon lithography enables the manufacturing of tailored 3D objects with high precision. Mechanical properties of materials can be accessed through micromechanical testing. This study presents an approach to overcome the issue of undefined geometries by introducing a slight taper within the geometry at initially printed layers.