The research is directed from the theoretical aspect to the development of the design of a new grinder, characterized by low energy and metal consumption. The work investigates the relationship of geometric parameters and speed modes of operation with quantitative and qualitative indicators of the screw cutter system. It is possible to increase the degree of chopping of the stems only by reducing the average cut length, i.e. by increasing the rotational speed screw knife. The experiments shows the average slice lengths and the corresponding productivity of the screw cutting pair depending on the speed of rotation of the knife. That for compliance with zootechnical requirements, modes n= 550-650 rpm.( lav = 8-4,5 sm ) - with vertical loading, and n=400-450rpm (lav = 5,5-4 sm) – at inclined feed at an angle β = 450. An increase in the frequency of rotation of the knife leads to a sharp decrease in the productivity of the cutting pair. The above numerical examples are selected in accordance with the parameters of the experimental setup and show good agreement with the experimental results.