<p>In the republic, the volumes of harvesting of hard-to-clean breeding varieties «S-6524», «Sulton», «An-Bayaut-2», «Namangan-77», «Omad» and others have increased annually. In 2018, their share amounted to 80% of the total harvest. With each year, the volume of harvesting raw co on of machine harvest is increasing. e weediness of raw co on at machine gathering is 10-15% more than manual. e peel with ber, broken seeds and nodules are formed in the process of ginning and, therefore, they can only be removed when gin ning raw co on. In order to improve the quality of the ber, in the mid-80s, two individual grates were installed in the gin itself for cleaning the ber. But due to the aws in the mounting structure of the individual grates on the side walls of the gin, it is impossible to establish the required gaps between the saw teeth and the edges of the grates, which reduces the release of hives and trash, as well as increased waste ber. In developed co on-growing countries such as the USA, China, India, etc., ber cleaning sections are not used in the construction of gins. ey have ber cleaned on berglass aerodynamic and condenser type. In this case, the ber is subjected to enhanced cleaning according to the principle of scratching, which increases the ber content of the waste, thereby reducing the amount of ber produced by grades. Improving the quality of ber, reducing waste losses and competitiveness in the global market is an urgent task. To achieve these goals, a modernized saw gin with a grate of a new design for ber cleaning has been created. A theoretical study was made on the change in the mass of a piece of brous material that occurs in the process of shock interaction with the grate is theoretically studied.</p>