DETERMINATION OF THE OPTIMAL GRINDING MODES FOR CUTTING TOOLS USING THE PLANNING METHOD OF EXPERIMENT

Abstract

Belt grinding is an effective method of machining as well as restoring tools and machine parts. It ensures high surface quality and productivity. Due to the flexibility of the abrasive belt, thermal damage is reduced, hardness is preserved, durability of the processed components is increased. The work focuses on improving the process of restoring cutting tools in shearing machines through belt grinding. The study highlights the shortcomings of traditional sharpening methods and emphasizes the advantages of abrasive belt grinding. To optimize sharpening, a full factorial experiment with three variables was carried out: belt speed, sharpening time, and pressing force. Both movable and stationary knives were tested under controlled conditions, and surface roughness was measured using a profilometer, microhardness was measured using a hardness tester. Regression equations were derived to model the influence of technological parameters on surface roughness, and statistical methods (Student’s t-test, Cochran’s G-test, Fisher’s F-test) were applied to validate the models. Experimental results showed that the optimal sharpening parameters are belt speed of 1.7 m/s, pressing force of 18 N, sharpening time of 19 s for stationary and 12 s for movable knives. These conditions ensure surface roughness within the 9th grade of finish (Ra = 0.16…0.32 μm), preserve tool hardness at HRA 84, and prevent thermal damage. Overall, the research provides a scientifically grounded methodology for setting sharpening regimes that extend tool life and improve shearing machine performance.