Process parameters Feature 1 Feature 2 Diameter (mm) 60.89 173.02 Cutting speed (RPM) 1800 1800 Feed (mm/blade) 0.15 0.15 Depth of cut (mm) 0.5 0.5 Lead angle ([degree]) 5 0 Axial rake ([degree]) 5 5 Radial rake
([degree]) 2 2 Nose radius (mm) 0.79 0.79 Predicted forces Cutting force (N) 94 102 Feed force (N) 22 32 Radial force (N) 30 40 TABLE 4 Predicted bore dimensions.
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 four curved helical cutting edges ensure positive radial rake
angles and soft penetration into the material being cut.
The radial rake
and the back clearance angles were 19 and 16 degrees, respectively.
A new indexable solid carbide ball nose end head was used in this experiment, type SECO TOOLS Minimaster B120P with coating code F30M, with 2-flute, 4 mm radius, helix angle and radial rake
angle of 0[degrees].
Angle: The angle between the tooth face and a cutter radius, measured in a plane normal to the cutter axis.
Because of the use of larger radial rake
angles and the unique geometry, the chips are easily deformed and the side walls remain perpendicular.
Positive radial rake
cuts softer and with less pressure, using less horsepower, creating less heat, and resulting in less strain on machine bearings, ways, and spindle." He compares positive-geometry milling to a planer on wood, where the work material is lifted up and peeled off.
There has been a progression in the geometry of milling cutters from negative axial rake/negative radial rake
to positive/positive configurations and, more recently, to High Positive configurations-so called because of greater than normal rake angles, i.e., typically 10 and 10 deg.
Negative radial rake
provides strong cutting edges, while positive rake creates a shearing action.
The negative axial-negative radial rake
milling cutter is one of four standard geometries available.