Siemens SINUMERIK 840D sl Programming Manual page 535

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.
Example: Various feed profiles
This example shows you the programming and graphic representation of various feed
profiles.
Program code
N1 F1000 FNORM G1 X8 G91 G64
N2 F2000 X7
N3 F=FPO(4000, 6000, -4000)
N4 X6
N5 F3000 FLIN X5
N6 F2000 X8
N7 X5
N8 F1000 FNORM X5
N9 F1400 FCUB X8
N10 F2200 X6
N11 F3900 X7
N12 F4600 X7
N13 F4900 X5
N14 FNORM X5
N15 X20
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
8.2 Feedrate response (FNORM, FLIN, FCUB, FPO)
Comments
; Constant feedrate profile, incremental
dimension data
; Setpoint velocity step change
; Feed profile via polynomial with feed 4000
at the end of the block
; Polynomial feedrate 4000 is valid as modal
value
; Linear feedrate profile
; Linear feedrate profile
Linear feedrate is valid as modal value
; Constant feedrate profile with acceleration
step change
; All of the following F values programmed in
blocks are connected with splines
; Switch-out spline profile
Path traversing behavior
535