Siemens SINUMERIK 840Di sl - 5.2 Tool offset

Motion commands
4.16 Linear progressive/degressive thread pitch change (G34, G35)
Fundamentals
174 Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
F
Thread lead change (in mm/rev
2
)
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
2
e
- k
2
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
G
: Thread length in [mm]
SF=
Starting point offset, only needed for multiple threads
Example of lead decrease
N1608 M3 S10
;Spindle speed
N1609 G0 G64 Z40 X216
;Approach start point and thread
N1610 G33 Z0 K100 SF=R14
;With constant pitch 100 mm/rev
N1611 G35 Z-200 K100 F17.045455
;Lead decrease 17.0454 mm/rev
2
;lead at block end 50 mm/rev
N1612 G33 Z-240 K50
;Traverse thread block without jerk
N1613 G0 X218
;
N1614 G0 Z40
;
N1615 M17
;