Siemens SINUMERIK 840D sl Programming Manual page 269

9.14 Fast retraction for thread cutting (LFON, LFOF, DILF, ALF, LFTXT, LFWP, LFPOS, POLF, POLFMASK,
Note
LFON or LFOF can always be programmed, but the evaluation is performed exclusively
during thread cutting (G33).
Note
POLF with POLFMASK/POLFMLIN are not restricted to thread cutting applications.
Examples
Example 1: Enable fast retraction for thread cutting
Program code
N55 M3 S500 G90 G18
...
N65 MSG ("thread cutting")
MM_THREAD:
N67 $AC_LIFTFAST=0
N68 G0 Z5
N68 X10
N70 G33 Z30 K5 LFON DILF=10 LFWP ALF=7
N71 G33 Z55 X15
N72 G1
N69 IF $AC_LIFTFAST GOTOB MM_THREAD
N90 MSG ("")
...
N70 M30
Example 2: Deactivate fast retraction before tapping
Program code
N55 M3 S500 G90 G0 X0 Z0
...
N87 MSG ("tapping")
N88 LFOF
N89 CYCLE...
N90 MSG ("")
...
N99 M30
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Comment
; Active machining plane
; Approach of the starting position
; Feed of the tool
; Reset before starting the thread.
; Enable fast retraction for thread
cutting.
Retraction path = 10 mm
Retraction plane: Z/X (because of G18)
Retraction direction: -X
(with ALF=3: Retraction direction +X)
; Deselect thread cutting.
; If thread cutting has been
interrupted.
Comment
; Deactivate fast retraction before tapping.
; Tapping cycle with G33.
Motion commands
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