Siemens SINUMERIK 840Di sl Programming Manual page 182

Motion commands
4.19 Stop with thread cutting (LFOF, LFON, LFTXT, LFWP, LFPOS)
Parameters
LFON
LFOF
LIFTFAST
DILF
ALF
Note
LFON or LFOF can always be programmed, they are evaluated only during thread cutting
(G33).
Example of enabling fast retraction in tapping
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=3
N71 G33 Z55 X15 K5
N72 G1
N69 IF $AC_LIFTFAST GOTOB MM_THREAD
N90 MSG ("")
...
N70 M30
182
Enable fast retraction for thread cutting (G33)
Disable fast retraction for thread cutting (G33)
Fast retraction option acts with LFON in every retraction direction
Determine retraction path (length)
Define retraction direction for plane to be executed (LFTXT)
Retraction path =10mm, retraction plane Z/X (due to G18)
Retraction direction -X (with ALF=3; retraction direction +X)
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
;Active machining plane
;Approach start position
;Tool infeed
;Reset before beginning of
;thread
;Enable fast retraction for thread ;cutting
;Deselect thread cutting
;If thread cutting was ;interrupted
Fundamentals