Path Traversing Behavior; Feedrate Characteristic (Fnorm, Flin, Fcub, Fpo) - Siemens SINUMERIK 840D sl Programming Manual

Work preparation

3.14 Path traversing behavior

3.14 Path traversing behavior
3.14.1

Feedrate characteristic (FNORM, FLIN, FCUB, FPO)

To permit flexible definition of the feedrate characteristic, the feedrate programming according
to DIN 66025 has been extended by linear and cubic characteristics.
The cubic characteristics can be programmed either directly or as interpolating splines. These
additional characteristics make it possible to program continuously smooth velocity
characteristics depending on the curvature of the workpiece to be machined.
These additional characteristics make it possible to program continuously smooth velocity
characteristics depending on the curvature of the workpiece to be machined.
Syntax
F... FNORM
F... FLIN
F... FCUB
F=FPO(...,...,...)
Meaning
FNORM:
FLIN:
FCUB:
F=FPO... :
Feed optimization on curved path sections
Feed polynomial F=FPO and feed spline FCUB should always be traversed at constant
cutting rate CFC, thereby allowing a jerk-free setpoint feed profile to be generated. This
enables creation of a continuous acceleration setpoint feed profile.
834
Basic setting. The feed value is specified as a function of the traverse path of the block
and is then valid as a modal value.
Path velocity profile linear:
The feed value is approached linearly via the traverse path from the current value at the
block beginning to the block end and is then valid as a modal value. The response can
be combined with G93 and G94.
Path velocity profile cubic:
The blockwise programmed F values (relative to the end of the block) are connected by
a spline. The spline begins and ends tangentially with the previous and following defined
feedrate and takes effect with G93 and G94.
If the F address is missing from a block, the last F value to be programmed is used.
Polynomial path velocity profile:
The F address defines the feed characteristic via a polynomial from the current value to
the block end. The end value is valid thereafter as a modal value.
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming