Tiger 370 CNC--MR, Use And Maintenance Manual

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MEP S.p.A.
9--6 150
Use and maintenance manual TIGER 370 CNC--MR
POSITIVE AND NEGATIVE CUTTING ANGLES
The cutting angle
γ
may vary from positive to negative depending on the cutting
speed, the profile and the type of material to be cut.
A positive angle
γ
determines better penetration of the tool and hence lower
shear stress and greater ease of sliding for the swarf over the cutting edge. On the
other hand, the cutting edge has lower mechanical resistance, so as the breaking
load of the material to be cut increases, the cutting angle decreases from positive
until it becomes negative so as to offer a cutting edge with a larger resistant
section.
B
γ
Positive
Short swarf material such as brass, bronze, aluminium and hard cast iron require
smaller cutting angles because the swarf becomes crushed immediately and the
rake angle has little effect during the cutting stage.
The TIGER 370 CNC---MR uses discs with positive cutting angles for cutting solid
materials and with negative cutting angles for cutting hollow profiles. This is
because, as a result of the high cutting speeds (2900 rpm), even with non---ferrous
materials the tool ”strikes” against the wall of the profile to be cut several times,
thus requiring a cutting edge with a larger resistant section.
B
γ Negative