Siemens SINUMERIK 840D sl Programming Manual page 147

Further information
Constant feedrate on contour with CFC
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
7.9 Feedrate optimization for curved path sections (CFTCP, CFC, CFIN)
The feedrate is reduced for inside radii and
increased for outside radii. This ensures a
constant speed at the tool edge and thus at
the contour.
Feed control
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