Siemens SINUMERIK 840D Programming Manual page 198

Milling Cycles
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3.15 Pocket milling with islands - CYCLE73, CYCLE74, CYCLE75
_FAL (final machining allowance in the plane)
The final machining allowance only affects
machining of the pocket in the plane at the edge.
When the final machining allowance ≥ tool diameter,
the pocket will not necessarily be machined
completely.
_FALD (final machining allowance on the base)
A separate final machining allowance on the base is
taken into account in roughing operations.
_FFD and _FFP1 (feedrate for depth infeed and
surface machining)
Feedrate _FFD is used for insertion into the material.
Feedrate FFP1 is used for all movements in the plane
traversed at feedrate when machining.
_CDIR (milling direction)
The value for the machining direction of the pocket is
defined in this parameter.
Under parameter _CDIR the mill direction
• direct "2 for G2" and "3 for G3" or
• alternatively "climb milling" or "opposed milling"
can be programmed. Climb milling or opposed
milling is determined within the cycle via the spindle
direction activated prior to the cycle call.
Climb milling
M3 → G3
M4 → G2
_PA, _PO (start point for first and second axes)
When the start point is selected manually, the start
point must be programmed in these parameters such
that it can be approached without risk of collision. It
must be noted that only one start point can be
programmed (see description of parameter _VARI).
3-198
Opposed milling
M3 → G2
M4 → G3
SINUMERIK 840D/840Di/810D/FM-NC Programming Guide, Cycles (PGZ) - 04.00 Edition
Y
G3
G2
G2
G3
 Siemens AG 2000 All rights reserved.
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