In the last few years, several approaches were researched for using AR technology in production engineering. Assembly and maintenance scenarios are typical fields of application for it. AR approaches were introduced which support workers with dissolved virtual instructions for assembling or repairing a machine tool. Such systems show animations and graphical hints (e.g. virtual arrows). Users of the system can see where a part has to be applied and which tools are needed. Another benefit is that all instructions are shown in the right order. Therefore, workers can also maintain machine tools which are unfamiliar. No time consuming teaching is necessary because the required knowledge is stored in databases. [1]