An indexable milling cutter includes a milling cutter body with a plurality of flutes and a plurality of seating surfaces adapted to mount a cutting insert thereon. The milling cutter body includes a plurality of coolant reservoirs in fluid communication with an adapter. In one aspect, each coolant reservoir lies along a circular intersection line of a coolant manifold. In another aspect, a longitudinal axis of each coolant reservoir is oriented at a non-zero angle, A, with respect to a central, longitudinal axis of the milling cutter. A plurality of coolant ducts in fluid communication with each coolant reservoir, each coolant duct having a smaller cross-sectional area than the coolant reservoir, provide multiple streams of coolant targeted at a plurality of specific critical cutting areas of the cutting insert.

A method for milling a workpiece by way of at least one substantially polygonal cutting insert, which is arranged in a tool holder. A spindle axis of the tool holder encloses an angle of more than 0° with a plane normal to a machined workpiece surface. An effective lead angle between a main cutting edge of the cutting insert and the machined workpiece surface lies between 0° and 20°.

A cutting insert includes a base body and a coating layer, and also includes a rake surface, a flank surface, and a cutting edge located along an intersecting ridge therebetween. The rake surface includes an outer peripheral part and a middle part protruded relative to the outer peripheral part. The middle part includes a constraining surface. The outer peripheral part includes a first breaker part, a second breaker part, and the third breaker part adjacent to the constraining surface. The constraining surface is configured by the base body and the coating layer does not exist at the constraining surface. A skewness Rsk of a roughness curve at the constraining surface is −1.5 μm to −0.5 μm. A skewness Rsk at the third breaker part is −0.2 μm or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

An indexable milling cutter includes a milling cutter body with a plurality of flutes and a plurality of seating surfaces adapted to mount a cutting insert thereon. The milling cutter body includes a plurality of coolant reservoirs in fluid communication with an adapter. In one aspect, each coolant reservoir lies along a circular intersection line of a coolant manifold. In another aspect, a longitudinal axis of each coolant reservoir is oriented at a non-zero angle, A, with respect to a central, longitudinal axis of the milling cutter. A plurality of coolant ducts in fluid communication with each coolant reservoir, each coolant duct having a smaller cross-sectional area than the coolant reservoir, provide multiple streams of coolant targeted at a plurality of specific critical cutting areas of the cutting insert.

A method for milling a workpiece by way of at least one substantially polygonal cutting insert, which is arranged in a tool holder. A spindle axis of the tool holder encloses an angle of more than 0 with a plane normal to a machined workpiece surface. An effective lead angle between a main cutting edge of the cutting insert and the machined workpiece surface lies between 0 and 20.

An indexable rotary cutting tool and insert is capable of performing a high-accuracy cutting process with high efficiency. A twist angle of an outer peripheral cutting edge of the tool has a positive value, an axial rake angle of the cutting edge of a corner R of the tool at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at a reference point has a negative value, and the radial rake angle at least between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value. The radial rake angle at the reference point is smaller than the radial rake angle at the boundary point.

An indexable rotary cutting tool comprising, a twist angle of the outer peripheral cutting edge having a positive value, an axial rake angle of the cutting edge of the corner R at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at the reference point has a negative value, at least the radial rake angle in a region between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value, and the radial rake angle of the cutting edge of the corner R at the reference point is smaller than the radial rake angle of the cutting edge of the corner at the boundary point.

A cutting insert includes a base body and a coating layer, and also includes a rake surface, a flank surface, and a cutting edge located along an intersecting ridge therebetween. The rake surface includes an outer peripheral part and a middle part protruded relative to the outer peripheral part. The middle part includes a constraining surface. The outer peripheral part includes a first breaker part, a second breaker part, and the third breaker part adjacent to the constraining surface. The constraining surface is configured by the base body and the coating layer does not exist at the constraining surface. A skewness Rsk of a roughness curve at the constraining surface is ?1.5 ?m to ?0.5 ?m. A skewness Rsk at the third breaker part is ?0.2 ?m or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

A cutting tool of an aspect is provided with a holder and a cutting insert attached to an insert pocket of the holder. The cutting insert includes a front end surface, a rear end surface, a front side surface, a rear side surface, an outer side surface, and an inner side surface. The cutting edge is disposed along a ridge line at an intersection between the front side surface and the front end surface, and a ridge line at an intersection between the front side surface and the outer side surface. The insert pocket includes a restraining surface that is in contact with the rear side surface, in a front end view, the restraining surface includes a projecting portion having a curved line shape projecting toward the front in the rotational direction, and the rear side surface includes a recessed portion that is in contact with the projecting portion.

A cutting insert with a first flat and major cutting edges in order in an intersection region of a first side surface and an upper surface, and a second flat and major cutting edges in order in an intersection region of a second side surface and upper surface. The first and second side surfaces include respective first and second chamfered side surfaces, respective first and second corner side surfaces, and respective first and second major side surfaces in order. The intersection region of the second side surface and upper surface includes a first intersection region of the second chamfered side surface and upper surface, and a second intersection region of the second corner side surface and upper surface. The second flat cutting edge is located from the first intersection region to the second intersection region, and has a lowermost portion in the first intersection region in a side view.