Siemens SINUMERIK 840D sl Function Manual page 1325

Dynamic response of the retraction motion
The retraction motion is executed with maximum axis dynamic response:
● MD32000 $MA_MAX_AX_VELO[<axis>] (velocity)
● MD32300 $MA_MAX_AX_ACCEL[<axis>] (acceleration)
● MD32431 $MA_MAX_AX_JERK[<axis>] (jerk)
Example
Program code
N55 M3 S500 G90 G18
...
N65 MSG ("thread cutting")
MM_THREAD:
N67 $AC_LIFTFAST=0
N68 G0 Z5
N69 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
N55 M3 S500 G90 G0 X0 Z0
...
N87 MSG ("tapping")
N88 LFOF
N89 CYCLE...
N90 MSG ("")
...
N99 M30
Behavior at power on and reset
After power on and reset, the following settings are activated:
● Initial settings for the retraction motion (LFON /LFOF) and retraction direction (LFTXT/
LFWP): MD20150 $MC_GCODE_RESET_VALUES
● Retraction path: MD21200 $MC_LIFTFAST_DIST
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Comment
; Set active machining plane.
; 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 di-
rection +X).
; Deselect thread cutting.
; If thread cutting has been interrupted.
; Deactivate fast retraction before tapping.
; Tapping cycle with G33.
V1: Feedrates
17.2 Path feedrate F
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