Thearticlegives the calculationdiagrams of the sieve modules for grain cleaning machines whichallow to analyze the operation of the grain cleaning machines, and the trajectory of materials moving within the machine. A generalized mathematical model of the functioning of air-sieve machines and sieve modules is presented. Based on the regression equations adequately describing the processes occurring on the sieves, the simulation of the calculation schemes of the sieve modules of grain cleaning machineswas carried out.The modeling results, such as the purity of the grain material, the completeness of the separation of impurities, the content of weed and grain impurities are presented in the form of dependencies, allowing them to be analyzed and selected the most efficient grain cleaning machine for the production line of seed material.