Siemens SINUMERIK 840D Programming Manual page 124

3
Milling Cycles
3.3 Thread cutting – CYCLE90
Sequence of operations
Outside threads
Position reached prior to cycle start:
This can be any position from which the starting
position on the outside diameter of the thread at the
retraction plane level can be reached without
collision.
This start position for thread milling with G2 lies
between the positive abscissa and the positive
ordinate in the current level (i.e. in the 1st quadrant
of the coordinate system). For thread milling with
G3, the start position lies between the positive
abscissa and the negative ordinate (i.e. in the 4th
quadrant of the coordinate system).
The distance from the thread diameter depends on
the thread size and the tool radius used.
The cycle implements the following motion
sequence:
• Travel to the starting point with G0 at the retraction
plane level in the applicate of the current plane
• Infeed to the reference plane brought forward by
the safety distance with G0
• Movement to the thread diameter along a circular
path in the direction G2/G3 opposite to that
defined in CDIR
• Thread milling along a helical path with G2/G3
and feedrate FFR
• Travel-out movement along a circular path in the
opposite direction G2/G3 and the reduced
feedrate FFR
• Retraction to retraction plane in the applicate with
G0
3-124
Z
Start position for
thread milling
with G3
SINUMERIK 840D/840Di/810D Programming Guide Cycles (PGZ) – 11.02 Edition
3
12.97
Y
X
Start position for
thread milling
with G2
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