Siemens SINUMERIK 840D sl Programming Manual page 697

In this case, compression is executed in two different ways, depending on whether large-radius
circular interpolation is executed. If no large-radius circular interpolation takes place, then the
compressed change in orientation is represented in the usual way by axial polynomials for the
rotary axes.
Contour accuracy
Depending on the selected compression mode (MD20482 $MC_COMPRESSOR_MODE)
either the configured axis-specific tolerances (MD33100 $MA_COMPRESS_POS_TOL) or the
following channel-specific tolerances – set using setting data – are effective for the geometry
axes and orientation axes for compression:
SD42475 $SC_COMPRESS_CONTUR_TOL (maximum contour deviation)
SD42476 $SC_COMPRESS_ORI_TOL (maximum angular deviation for tool orientation)
SD42477 $SC_COMPRESS_ORI_ROT_TOL (maximum angular deviation for the angle of
rotation of the tool) (only available on 6-axis machines)
Activation/deactivation
Compressor functions are activated using the modal G commands COMPCAD and
COMPSURF.
COMPOF terminates the compressor function.
See " AUTOHOTSPOT ".
Note
Orientation motion is only compressed when large radius circular interpolation is active (i.e. tool
orientation is changed in the plane, which is determined by start and end orientation).
Large-radius circular interpolation is performed under the following conditions:
● MD21104 $MC_ORI_IPO_WITH_G_CODE = 0,
ORIWKS is active and
the orientation is programmed as a vector (with A3, B3, C3 or A2, B2, C2).
● MD21104 $MC_ORI_IPO_WITH_G_CODE = 1 and
ORIVECT or ORIPLANE is active.
The tool orientation can be programmed either as a direction vector or with rotary axis
positions. No large radius circle interpolation is performed, if one of the G commands
ORICONxx or ORICURVE is active, or if polynomials for orientation angle (PO[PHI] and
PO[PSI]) are programmed.
Example
In the example program below, a circle approximated by a polygon definition is compressed.
The tool orientation moves on the outside of the taper at the same time. Although the
programmed orientation changes are executed one after the other, but discontinuously, the
compressor function generates smooth orientation motion.
Programming
DEF INT NUMBER=60
DEF REAL RADIUS=20
NC programming
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
Comment
Work preparation
3.9 Transformations
697