In SIGMA are two methods of cost accounting, the full cost calculation and the machine hour rate calculation. The calculation of the machine hour rate sums up all machine dependent costs, for example energy and occupancy costs. This calculation is useful to compare two machines with different screw diameters on cost basis. The full cost calculation method includes all costs of one period, so that the user can see all costs which incur in a period. In the following section, both calculation methods will be explained.