Concerns the fabrication of miniaturized optical devices with height attachment precision. For active alignment of micro-optical elements machined with tolerances lower than the intended precision, an accurate 6-DOF robot is needed. This article describes such a structure, which is named Sixtiff. Sixtiff was first developed for the use of a new optical assembly technology, TRIMO-SMD. The robot is a hybrid serial-parallel structure composed of five linear stages and one angular stage. It has a stiff structure, without floating