Milling tool, a cutting insert for milling tool as well as a solid milling tool

An indexable milling insert having a polygonal basic shape and cutting geometry, comprising

• a top side,
• a bottom side,
• four peripherical sides, two of the four peripherical sides forming a pair of first, mutually opposite sides and another two of the four peripherical sides forming a pair of second, mutually opposite sides that meet the pair of first, mutually opposite sides at corners, as well as
• two material-cutting edges formed between a chip surface on the top side of the insert and clearance surfaces along the periphery sides,
• wherein
• the chip surface is inclined in a first direction in relation to a neutral plane parallel to the bottom side of the insert, so that a distance between the neutral plane and an end of the chip surface that is situated farthest from an appurtenant edge is smaller than a distance between the neutral plane and other parts of the chip surface,
• an angle of inclination (σ) of the chip surface in said first direction in relation to the neutral plane is within the range of 3-15°,
• the two cutting edges in cross-section each have an arc-shape having a radius of curvature within the range of 5-20 μm,
• the clearance surfaces are each formed with a clearance bevel, which extends from one of the two cutting edges in a direction of the bottom side to a main clearance portion,
• an angle of inclination (ε) of the clearance bevel in relation to a reference plane orthogonal to the neutral plane and touching one of the two cutting edges is larger than 10°, but smaller than 28°,
• a clearance angle (Ω) of the main clearance portion in relation to a reference plane touching one of the two cutting edges is larger than the clearance angle (ε) of the clearance bevel,
• an extension of the clearance bevel from one of the two cutting edges to the main clearance portion is within the range of 0.05-0.30 mm,
• the chip surface is formed with a reinforcement bevel, which extends from one of the two cutting edges in the direction of the centre of the cutting insert and transforms into a main chip portion, an angle of inclination (φ) of the reinforcement bevel in relation to the neutral plane being larger than −30°, but smaller than −5°, and
• an extension of the reinforcement bevel from one of the two cutting edges to the main chip portion is within the range of 0.05-0.15 mm.

A solid milling tool for chip-removing machining, comprising

• a basic body rotatable around a geometrical centre axis in which body a plurality of peripherically spaced-apart chip channels are formed, each chip channel being provided with an appurtenant edge formed between a chip surface and a clearance surface along a periphery side of the milling tool, the chip surface is inclined in relation to the centre axis while forming a positive angle of inclination,
• wherein
• a value of the angle of inclination (θ) between the chip surface and the centre axis is within the range of 25-28°,
• a cutting edge cross section-wise has an arc-shape having a radius of curvature within the range of 5-20 μm,
• the clearance surface is formed with a clearance bevel, which extends from the cutting edge in a periphery direction of the milling tool to a main clearance portion,
• a clearance angle (γ) of the clearance bevel is larger than 0°, but smaller than 3°,
• a clearance angle (ω) of the main clearance portion is larger than the clearance angle (γ) of the clearance bevel,
• an extension of the clearance bevel from the cutting edge to the main clearance portion is within the range of 0.05-0.30 mm,
• the chip surface is formed with a reinforcement bevel, which extends from the cutting edge in a direction radially inward toward the centre of the milling tool to a main chip portion, an angle of inclination (ψ) of the reinforcement bevel in relation to the centre axis being larger than −5°, but smaller than +5°,
• an extension of the reinforcement bevel from the cutting edge to the main chip portion is within the range of 0.05-0.15 mm.