Siemens SINUMERIK 840Di sl Programming Manual page 174

Motion commands
4.16 Linear progressive/degressive thread pitch change (G34, G35)
F
SF=
Example of lead decrease
N1608 M3 S10
N1609 G0 G64 Z40 X216
N1610 G33 Z0 K100 SF=R14
N1611 G35 Z-200 K100 F17.045455
N1612 G33 Z-240 K50
N1613 G0 X218
N1614 G0 Z40
N1615 M17
174
Thread lead change (in mm/rev
If you already know the initial and final lead of a thread, you can
calculate the lead change to be programmed according to the
following equation:
|k - k |
2 2
e a
F = ------------- [mm/rev ]
2
2*I
G
The identifiers have the following meanings:
Ke: thread lead of axis target point coordinate in [mm/rev]
Ka: initial thread pitch (progr. under I, J, and K) in [mm/rev]
I : Thread length in [mm]
G
Starting point offset, only needed for multiple threads
;Spindle speed
;Approach start point and thread
;With constant pitch 100 mm/rev
;Lead decrease 17.0454 mm/rev
;lead at block end 50 mm/rev
;Traverse thread block without jerk
;
;
;
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
)
2
2
Fundamentals