Programming
10.5 Special functions
Surface grinding
258 Programming and Operating Manual, 11/2012, 6FC5398-5CP10-3BA0
Upper speed limit LIMS=
During machining from large to small diameters, the spindle speed can increase significantly.
In this case, it is recommended the upper spindle speed limitation LIMS=... . LIMS is only
effective with G96 and G97.
By programming LIMS=..., the value entered into the setting data (SD 43230:
SPIND_MAX_VELO_LIMS) is overwritten. This SD takes effect when LIMS is not written.
The upper limit speed programmed with G26 or defined via machine data cannot be
overwritten with LIMS=.
Deactivate constant cutting rate: G97
The function "Constant cutting rate" is deactivated with G97. If G97 is active, a programmed
S word is given in RPM as the spindle speed .
If no new S word is programmed, the spindle turns at the last defined speed with G96
function active.
Programming example
N10 ... M3 ; Spindle's direction of rotation
N20 G96 S120 LIMS=2500 ; Activate constant cutting speed, 120 m/min, speed
limit 2,500 r.p.m.
N30 G0 X150 ; no change in speed, because block N31 with G0
N31 X50 Z... ; no change in speed, because block N32 with G0
N32 X40 ; Approach on contour, new speed is automatically set as
is required for the beginning of block N40
N40 G1 F0.2 X32 Z... ; Feedrate 0.2 mm/revolution
...
N180 G97 X... Z... ; Deactivating constant cutting rate
N190 S... ; new spindle speed, r.p.m.
Information
The G96 function can also be deactivated with G94 or G95 (same G group). In this case, the
last programmed spindle speed S is active for the remaining machining sequence if no new
S word is programmed.
The programmable offset TRANS or ATRANS (see section of that name) should not be used
on the transverse axis X or used only with low values. The workpiece zero point should be
located at the turning center. Only then is the exact function of G96 guaranteed.