Siemens SINUMERIK 840D Function Manual page 127

A group of G commands is provided for this purpose:
● CFTCP
Programmed feedrate acting on the center point path.
● CFC
Programmed feedrate acting on the contour.
● CFCIN
Programmed feedrate acting only on the contour with a concave spline.
Further information
Programming Manual Fundamentals
Maximum tool path velocity
The maximum path velocity results from the maximum velocities of the linear or rotary axes
involved (MD32000 $MA_MAX_AX_VELO), i.e. the axis with the lowest maximum velocity
determines the maximum path velocity. This cannot be exceeded.
If G0 is programmed, traversing is at the path velocity resulting from the MD32000
$MA_MAX_AX_VELO limitation.
Limit velocity for path axes
In addition, the FL[<axis>] statement can be used to program a limit velocity for path axes
(geometry and synchronized axes).
This enables separate feedrates to be programmed for the working plane and infeed axis. This
means that a feedrate is specified for the path-related interpolation and for the infeed axis. The
axis perpendicular to the selected machining plane is designated as the infeed axis. The infeed
axis-specific feedrate can be programmed to limit the axis velocity and therefore the path
velocity. No coordinate rotations through frames should be included, i.e. the infeed axis must
be an axis of the standard coordinate system. This function can be used to compensate for the
fact that a cutter has a lower cutting performance on the face side than across the cutter
circumference.
Programming example:
Program code
... G94 ...
X30 Y20 F200
FL[Z]=50 Z-30
Low-resolution encoders
When using low-resolution encoders, more continuous path or axis motions can be achieved
with smoothed actual values. The larger the time constant, the better the smoothing of the
actual values, and the longer the overtravel.
MD34990 $MA_ENC_ACTVAL_SMOOTH_TIME[<axis>] (smoothing time constant for actual
values)
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
Comment
; Selection of feedrate type (mm/min)
; Path feedrate = 200 mm/s
; Max. feedrate for Z axis: 50 mm/s
V1: Feedrates
5.2 Path feedrate F
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