An automated door mechanism with a special motion sequence was required for a precise optical instrument. The construction has only limited space; only 3,8 cm are available. In addition, the solution shall be cost-efficient. igus® products are convincing: drylin® N miniature plain bearings are outstandingly suitable for limited space. Furthermore, other products such as iglidur® J thrust washers, iglidur® bushes and xiros® polymer plain bearings are used.