Fully automating the assembly of laser systems puts high demands on the accuracy, but alike on the flexibility and adaptivity of the assembly system. In this paper a concept for a flexible robot-based precision assembly is introduced. This concept is based on a modular 6-axis alignment tool which has been designed as a hybrid serial-parallel manipulator with flexures for all revolute and spherical joints. Technical insights on the design and dimensioning based on analytical calculations will be presented as well as first results from the characterization of a prototypal alignment module.