These angles are called: radial rake angle and axial rake
During the investigations, a toric milling tool with negative axial and radial rake angles, both with -6[degrees] and for comparison another toric tool with an axial rake
angle of +4[degrees] and a radial rake angle of -2[degrees] were used.
The two cutting edges slanted toward the center provide one side with strong and accurate clamping of the insert into the tool body, and the other side creates a positive axial rake
Inserts for this cutter have a helical curved edge that provides constant cutting rake all along the edge, and the positive axial rake
gives a smooth cutting action to minimize vibration and add stability.
Brochure highlights new generation tools with hard coating, including Modular-Grip (parting, turning, grooving, and facing in a single tool), PentaCut insert (five cutting edges for precision grooving, parting, and recessing), ChamDrillJet (internal coolant drill for aluminum engine heads), and HeliPlus (helical cutting edge and high axial rake
angle with two clamping screws), among others.
Angle: Measured between the peripheral cutting edge and the axis of the cutter, when looking radially at the point of intersection.
These inserts developed during the last decade possess a rake angle larger than the inserts' axial rake
. The concept of the helical-cutting-edge geometry with the non-parallel surfaces, as explained in the illustration on page 57, enables also a strong cutter body and high rigidity.
At another level, developments in cutting tools, which have edges of varying helix and axial rake
angles to prevent the onset of chatter, will create new markets for CNC controlled machines that could grind such complex cutter structures.
The two toward-center-slanted cutting edges provide on one side strong and accurate clamping of insert in the tool body, and on the other side, the positive axial rake
A higher axial rake
angle also improves metal removal rates.
And while carbide needs a large positive axial rake
- usually 25 deg - PCD-tipped inserts cut as low as 11 deg.