a multitooth or multiblade cutting tool in the form of a body of revolution, used to cut metals and other materials by milling.

Depending on their purpose, milling cutters are classified as cylindrical (plain), face, circular grooving (one-, two-, and three-sided), slitting, end, key-seat, T-slot, angle, and profile (including disk-type gear milling and end-milling type) cutters and hobs (see Figure 1). Cutters may also be classified according to the tooth cross section (sharp-pointed and relieved), the tooth shape (straight, helical, staggered), the direction of the helical grooves (right-handed, left-handed), the cutter design (solid, composite, cutters with inserted teeth or blades, and gang cutters), the mounting method (arbor-type and with a conical or cylindrical shank), and the material from which the cutting element is made (high-speed steel, hard alloy, and composition material).

Figures 2 and 3 give the geometric parameters of the cutting elements of the most widely used types of milling cutters—cylindrical plain and face cutters. The following ranges for optimum

Figure 1. Principal types of milling cutters: (1) cylindrical (plain), (2) face, (3) and (4) circular grooving, (5) slitting, (6) and (7) end, (8) angle, (9) and (10) profile, (11) key-seat

geometric parameters of the cutting elements have been experimentally established: –10°–30° for the rake angle γ, 10°–30° for the primary clearance angle α, 4°–10° for the secondary clearance angle α₁ 30°–90° for the side cutting edge angle ϕ, 1°—10° for

Figure 2. Geometric parameters of the cutting elements of a cylindrical plain cutter: (1) tooth face, (2) back of tooth, (3) relief surface, (4) helical side cutting edge of the tooth

the end cutting edge angle ϕ₁; 1–2 mm for the length of the transitional cutting edge l, –5°–15° for the rake angle of the primary cutting edge λ, and 10°–45° for the helix angle ω.

Milling productivity, cutter durability, the quality of the milled surfaces, and the cutting force are also influenced by other geometric

Figure 3. Geometric parameters of the cutting elements of a face cutter with hard alloy teeth: (1) side cutting edge, (2) transitional cutting edge

parameters of the milling cutter: the relief angle in a normal cross section α_n, the side rake angle γ’, the back rake angle γ”, and the transitional cutting edge angle ϕ₀.