Siemens SINUMERIK 840D Programming Manual page 159

3
12.97
Sequence of operations
Position reached prior to cycle start:
This can be any position from which the starting
position on the center point of the pocket at the
retraction plane level can be approached without
collision.
Motion sequence when roughing (VARI=X1):
With G0, the pocket center point is approached at the
retraction plane level and then, from this position, with
G0 the reference plane brought forward by the safety
distance is approached. Pocket machining is then
performed according to the selected insertion strategy
and considering the programmed base size.
Insertion strategies:
• Vertical insertion to pocket center (VARI=0X,
VARI=1X) means that the current infeed depth
internally calculated in the cycle ( ≤ programmed
maximum infeed depth through _MID) is executed in
one block with G0 or G1.
• Insertion along helical path (VARI=2X)
means that the milling center point travels on the
helical path determined by radius _RAD1 and depth
per revolution _DP1. The feedrate is always
programmed through _FFD. The sense of rotation of
this helical path corresponds to the direction to be
used for machining the pocket.
The depth programmed under _DP1 on insertion is
calculated as the maximum depth and is always
calculated as a whole number of revolutions of the
helical path.
When the current depth for the infeed (these may be
several revolutions on the helical path) has been
calculated, a full circle is made to remove the slope
on insertion.
Then pocket solid machining starts in this plane and
continues until reaching the final machining
allowance.
The starting point of the helical path described is on
the pocket longitudinal axis in the "plus direction"
and reached with G1.
© Siemens AG, 2002. All rights reserved
SINUMERIK 840D/840Di/810D Programming Guide Cycles (PGZ) – 11.02 Edition
3.9 Milling rectangular pockets – POCKET3
Y
Milling Cycles
G2
G3
3
X
3-159