Cutting blade with convex coating units on rear tool face

The cutting blade comprises a plate-shaped base body, the plate-shaped base body comprises an upper surface, a lower surface and side faces connected with the upper surface and the lower surface, the side faces and the upper surface intersect to form a plurality of cutting edge units, and each cutting edge unit comprises a main cutting edge, an angle cutting edge and an auxiliary cutting edge. The side face comprises a first rear cutter face and a second rear cutter face, the first rear cutter face is located above the second rear cutter face, the first rear cutter face is provided with a non-cutting area and a rear cutting area participating in cutting, and two cutting coatings are arranged on the first rear cutter face and include the first coating and the second coating located outside the first coating. Microcosmic components of all positions of the first coating are the same and completely cover the first rear cutter face, the second coating is composed of one or more convex coating units arranged in the