Siemens SINUMERIK 840D sl Function Manual page 1742

Detailed description
2.1 Path feedrate F
Retraction movement
The retraction motion (liftfast) for thread cutting is controlled by the following keywords:
• LFON
• LFOF
These G functions can always be programmed.
The default setting for NC Reset and/or NC Start is specified in machine data:
MD20150 GCODE_RESET_VALUES.
The following sources can initiate a retraction motion during thread cutting:
• Fast inputs (programming with SETINTLIFTFAST for "LIFTFAST" option)
• NC Stop
• Alarms that implicitly initiate the NC stop.
Figure 2-3
Retraction path
The retraction path can be configured in machine data:
MD21200 LIFTFAST_DIST.
If required, this path in the part program can be changed by writing DILF at any point.
Following an NC reset, the value entered in machine data:
MD21200 LIFTFAST_DIST
(default value) is always active.
26
⇒ Enable liftfast for thread cutting.
⇒ Disable liftfast for thread cutting.
Interruption of G33 through retraction motion
Basic logic functions: Feeds (V1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0