Siemens SINUMERIK 808D ADVANCED - Thread Cutting; Thread Cutting with Constant Lead: G33

Programming and Operating Manual (Milling)
6FC5398-4DP10-0BA1, 01/2014
79
If you wish the programmed feedrate always to act at the cutter center point path, then disable the feedrate override. The
modally acting G group that contains CFTCP/CFC (G functions) is provided for switching.
Programming
CFTCP ; Feedrate override OFF (the programmed feedrate acts at the milling cutter center point)
CFC ; Feedrate override with circle ON
See the following illustration for feedrate override G901 with internal/external machining:
Corrected feedrate
● External machining:
F
corr.
= F
prog.
(r
cont
+ r
tool
) / r
cont
● Internal machining:
F
korr.
= F
prog.
(r
cont
- r
tool
) / r
cont
r
cont
: Radius of the circle contour
r
tool
: Tool radius
Programming example
N10 G42 G1 X30 Y40 F1000
; Tool radius compensation ON
N20 CFC F350
; Feedrate override with circle ON
N30 G2 X50 Y40 I10 J-7 F350
; Feed value acts on contour
N40 G3 X70 Y40 I10 J6 F300
; Feed value acts on contour
N50 CFTCP ; Feedrate override OFF, programmed feedrate value acts at the
milling cutter center point
N60 M30
8.5
Thread cutting
8.5.1
Thread cutting with constant lead: G33
Functionality
This requires a spindle with position measuring system.
The function G33 can be used to machine threads with constant lead of the following type: If an appropriate tool is used,
tapping with compensating chuck is possible.
The compensating chuck compensates the resulting path differences to a certain limited degree.