Calculation of the machining parameters is one of the basic routine operations carried out before initializing the work and technological operations on a machine tool. Basis for calculating these parameters is obtained from the technical documentation in the form of rules, tables, catalogues and company literature. It can be concluded that this is a routine activity which represents a significant proportion of the activities performed before actual production of the product. It is exactly the routine activities that are possible to underpin and process well with the help of computers and appropriate application equipment. This contribution describes the design and implementation of a knowledge based system of calculation of the processing and operational machining parameters with the possibility of parameter correction with regard to specific technological equipment. The result is the obtaining of an optimal machine setting for machined range of products with a consideration for the production efficiency, durability of the cutting tool and the possibility of reusing the archived operational parameters.