Specifications

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CONCISE GUIDE FANUC 33
3.9 “G96” CONSTANT CUTTING SPEED
G96 sets the spindle rotation indicated by the code S as constant cutting speed (m/min). With this
function active the programmed S value is the surface speed in metres per minute (e.g.: S80, S100, S120,
S200, S350 etc.), this function continuously updates the actual spindle revolutions according to the work
diameter, keeping the cutting speed constant. It is a modal function and can be cancelled by
programming G97 (rpm set).
During the turning operations (rough machining, finishing,) it is recommended to always use G96; the S
values to be set depend on the type of material, the type of tool, the machining method and so forth.
Example:
N4 T303
N5 G96 S180 M4
N6 G0 X100 Z3 M8
Programming an S value with G96 active the number of revs can be calculated according to the work
diameter, using this formula:
To calculate the number of revs of machining performed at 150 m/min. on a diameter of 40:
Vt = 150 [m/min.]
π = 3.14
D = 40 mm
n = ? rpm.
n =
Vt x 1000
π
x D
Dove:
Vt => cutting speed [m/min]
π => 3.14
D => work diameter
n => rpm
1000 => m to mm conversion
n =
150 x 1000
3.14 x 40
= 1194