Designing process is one of the first phases of any artificial machine life-cycle. Machine tools are complicate machines thus designing process is often the most difficult phase of a machine life-cycle. Therefore this phase has the main influence on future machine features such as machine performance, rigidity, accuracy etc. In order to achieve the best possible design structure of machine it is necessary to understand whole life-cycle of some machine tool. The machine tool life-cycle can be different from other machines life-cycle because some machines tools can also pass through the retrofitting phase during its life.