Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 666)

Milling Fixed Cycles
Chapter 26
26-34
When using Method II, remember:
If both axes in the current plane are to be shifted, specify both
words to move the axes.
The move generated will be a single linear move and will execute
at rapid traverse.
3. The back boring tool moves at a rapid feedrate through the existing
hole to the depth designated by the R--word.
4. Once the designated depth is reached, the back boring tool shifts the
same distance but in the opposite direction as the previous shift (the
shift made in step 2).
After this shift, the programmer or operator must start spindle
rotation. The spindle must rotate in the clockwise direction.
5. The control retracts the back boring tool at the cutting feedrate to a
level specified by the Z--word.
6. After reaching the Z depth, the spindle rotation stops so that the
control can re-orient the back boring tool to the position specified in
AMP.
The back boring tool is shifted a third time, in the same manner as in
step 2, so that it is again “off-center” and can be removed through the
existing hole.
7. The back boring tool moves at a rapid feedrate to the initial point
level regardless of whether G98 or G99 are active.
8. The back boring tool is shifted a fourth time, in the same manner as
in step 2, returning to the initial X, Y coordinates of the hole location.
The format for the G88 cycle is:
G88X__Y__Z__R__P__F__L__;
Where : Is :
X,Y specifies location of the hole.
Z defines the hole bottom.
R defines the R point level.
P defines the dwell period at the hole bottom.
F defines the cutting feedrate.
L defines the number of times the milling fixed cycle is repeated.
(See section 26.3 for a detailed description of these parameters.)
(G88): Boring Cycle,
Spindle Stop/Manual Out