For this diploma thesis, the actual closing devices are analysed in order to define the problems of these systems. Afterwards solutions for these problems are sought to improve the existing system. The basic definitions and two important methods of cold forging are described in chapter 2. Chapter 3 shows an analysis of the current state of the art for better understanding the existing systems and for highlighting the associated problems. In chapter 4 the causes for breakdown are investigated for which in chapter 5 solutions will be offered. These solutions were recommended within the scope of a workshop and analysed to solve the problems, which were discovered during the analysis of the current state of the art of the existing systems. Chapter 6 will describe the tests, which were carried out in order to test new coating systems, new tools and new approaches concerning the tools. Within the scope of this thesis a simulation is also done to examine and demonstrate the effects of geometric variables (e.g.: angle) of the segments and their influences on the closing force and therefore on the overall tool. In the last chapter a conclusion and a future prospect are given.