Siemens Sinumerik 840D sl Programming Manual page 240

Motion commands
10.12 Chamfer, rounding (CHF, CHR, RND, RNDM, FRC, FRCM)
Syntax
Chamfer the contour corner:
G... X... Z... CHR/CHF=<value> FRC/FRCM=<value>
G... X... Z...
Round the contour corner:
G... X... Z... RND=<value> FRC=<value>
G... X... Z...
Modal rounding:
G... X... Z... RNDM=<value> FRCM=<value>
...
RNDM=0
Note
The technology (feedrate, feedrate type, M commands, etc.) for chamfer/rounding is derived
from either the previous or the next block dependent on the setting of bit 0 in machine data
MD20201 $MC_CHFRND_MODE_MASK (chamfer/rounding behavior). The recommended
setting is the derivation from the previous block (bit 0 = 1).
Meaning
CHF=... :
CHR=... :
RND=... :
RNDM=... :
FRC=... :
FRCM=... :
240
Chamfer the contour corner
Length of the chamfer (unit corresponding to G70/G71)
<value>:
Chamfer the contour corner
Width of the chamfer in the original direction of motion (unit correspond‐
<value>:
ing to G70/G71)
Round the contour corner
Radius of the rounding (unit corresponding to G70/G71)
<value>:
Modal rounding (rounding multiple contour corners in the same way one after the other)
Radius of the roundings (unit corresponding to G70/G71)
<value>:
Modal rounding is deactivated with RNDM=0.
Non-modal feedrate for chamfer/rounding
Feedrate in mm/min (with active G94) or mm/rev (with active G95)
<value>:
Modal feedrate for chamfer/rounding
Feedrate in mm/min (with active G94) or mm/rev (with active G95)
<value>:
FRCM=0 deactivates modal feedrate for chamfer/rounding and activates
the feedrate programmed under F.
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
Fundamentals