Abstract: A cemented carbide end mill has three or more cutting edges formed on its periphery and flutes each provided between adjacent cutting edges. The land width of each cutting edge and the flute width has a ratio of 1:1.5 to 1:4. Each flute has a helix angle of 35°-60° and, when viewed in a cross section perpendicular to the end mill axis, is in a shape smoothly concave radially inwardly. The core of the end mill has a diameter which is 62%-68% of the outer diameter of the end mill. The cutting edges have a base material of ultra-fine cemented carbide and are coated with a titanium-aluminum nitride hard film. The end mill is good at chip discharging in groove cutting and provides less inclination of cut grooves and less corner wear of the end mill.

Abstract: A cemented carbide end mill has three or more cutting edges formed on its periphery and flutes each provided between adjacent cutting edges. The land width of each cutting edge and the flute width has a ratio of 1:1.5 to 1:4. Each flute has a helix angle of 35°-60° and, when viewed in a cross section perpendicular to the end mill axis, is in a shape smoothly concave radially inwardly. The core of the end mill has a diameter which is 62%-68% of the outer diameter of the end mill. The cutting edges have a base material of ultra-fine cemented carbide and are coated with a titanium-aluminum nitride hard film. The end mill is good at chip discharging in groove cutting and provides less inclination of cut grooves and less corner wear of the end mill.