This chapter deals with the process planning for sequencing NC (numerical control) machining operations. This task of selecting and ordering of machining operations is still done manually in principle. In order to overcome this problem, an approach for enabling the automatic preparation of work plans with methods known from the graph theory is introduced in this chapter. Therefore a work plan is mapped into a directed graph in a mathematically defined way. Based on that, it is possible to use algorithms to find the shortest path and a Hamiltonian path inside this directed graph as optimal sequenced solution under given requirements. Thus, the work plan is structured and re-ordered. Finally the corresponding NC machining code will be generated and distributed to the machinery.