If material selection and heat treatment represent the art of blade manufacturing, grinding is the microscopic art that ultimately determines blade life. Blade grinding involves far more than simply shaping a blade. The blade material establishes only its theoretical maximum service life; its actual surface topography is created by countless microscopic cutting traces left by the abrasive grains in the grinding wheel. At the micron—and even submicron—scale, grinding forms the cutting edge, influences surface stresses, and either creates or eliminates microscopic defects. These factors directly affect cutting accuracy, durability, and service life. Grinding is therefore an invisible yet highly precise form of microscopic craftsmanship. The quality of a ground cutting edge directly influences cutting burrs, cut-edge flatness, and blade life. Consequently, the abrasive material, grit size, grade, and structure of a grinding wheel can profoundly affect blade flatness, surface finish, and even the metallurgical microstructure of the surface layer. To significantly improve knife surface quality, the grinding process must be carefully controlled to: · Eliminate microcracks along the knife cutting edge. · Produce the optimum edge radius. · Control residual stresses in the surface layer · Control knife surface texture and roughness · Prevent grinding burns and thermally affected layers on knives. Here is a selection of grinding-wheel types Typical Application rough-semi-finish-finish for knives Original criterion of Industry Department #25-#60 #60-#100 #100-#240 #240-W20 Reachable surface coarseness Ra0.8 Ra0.8-Ra0.4 Ra0.4-Ra0.2 Ra0.2-Ra0.05 Grinding wheel characteristics Brown fused alumina offers moderate hardness, high toughness, and good heat resistance. Rough grinding for the raw knife materials generally uses relatively coarse grit sizes, such as 46 to 60 grit. Vitrified bonds and open structures are commonly selected to provide high porosity and efficient chip clearance. Effect on blade characteristics Brown fused alumina is suitable for rapid stock removal when a large machining allowance is required. Although it provides high grinding efficiency and makes blade flatness relatively easy to control, it produces a comparatively poor surface finish. The resulting surface has a higher Ra value and clearly visible grinding marks. Effect on operating performance Brown fused alumina is primarily used for rough grinding of ordinary carbon steel blades and low-alloy tool steel knives such as 9CrSi knives. It can quickly remove heat-treatment scale and excess material. However, if it is used directly for finishing grinding, the rough cutting edge can increase friction during shearing, causing burrs on the processed material. 2. White Fused Alumina (WA): Efficient Finish Grinding of Hardened-Steel Blades Grinding-wheel characteristics White fused alumina is harder than brown fused alumina. Its abrasive grains have extremely sharp cutting edges, although the ...