Siemens SINUMERIK 840D Programming Manual page 139

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FFD and FFP1 (feedrate depth and plane)
Feedrate FFD is operative for vertical infeed to the
machining plane with G1 and for insertion with
oscillation motion.
Feedrate FFP1 is active for all movements in the plane
traversed at feedrate when roughing.
MID (infeed depth)
The maximum infeed depth is defined with this
parameter. The depth infeed is performed by the cycle
in equally sized infeed steps.
Using MID and the total depth, the cycle automatically
calculates this infeed which lies between 0.5x maximum
infeed depth and the maximum infeed depth. The
minimum possible number of infeed steps is used as
the basis. MID=0 means that the cut to slot depth is
made with one infeed.
The depth infeed commences at the reference plane
moved forward by the safety distance (as a function of
_ZSD[1]).
CDIR (milling direction)
You define the slot machining direction in this
parameter.
Under parameter _CDIR the mill direction
• direct "2 for G2" and "3 for G3" or
• alternatively "up-cut milling" or "down-cut milling"
can be programmed. Up-cut milling or down-cut
milling is determined within the cycle via the spindle
direction activated prior to the cycle call.
Up-cut milling
M3 → G3
M4 → G2
FAL (final machining allowance at slot edge)
With this parameter you can program a final machining
allowance on the slot edge. FAL does not affect the
depth infeed. If the value of FAL is greater than allowed
for the specified width and the milling cutter used, FAL
is automatically reduced to the maximum possible
value. In the case of rough machining, milling is
performed with a reciprocating movement and depth
infeed at both end points of the slot.
© Siemens AG, 2002. All rights reserved
SINUMERIK 840D/840Di/810D Programming Guide Cycles (PGZ) – 11.02 Edition
Down-cut milling
M3 → G2
M4 → G3
3.5 Slots on a circle – SLOT1
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Milling Cycles
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