Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 648)

Milling Fixed Cycles
Chapter 26
26-16
Figure 26.7
G76: Boring Cycle, Spindle Shift
Cutting feed
Rapid feed
Initial point
level
Shift Shift
Shift
Spindle orientation
after shift
Q
Q
Spindle orient after
dwell at Z point level
to position tool for
removal
Hole bottom
R point level
1
2
3
4
6
7
8
5
In the G76 boring cycle, the control moves the axes in this manner:
1. The tool rapids to the initial point level above the hole location.
2. The boring tool then rapids to the R point level, slows to the
programmed cutting feedrate and begins the boring operation.
3. The boring tool bores at the programmed feedrate to the
pre-programmed depth of the hole (defined by the Z--word in the
boring cycle block).
4. The control positions the spindle at the bottom of the hole in a
particular orientation, determined by the system installer in AMP.
5. To prevent the boring tool from damaging the sides of the bored hole
during retraction, the boring tool is shifted in either of two methods,
which are explained on the following page and illustrated in
Figure 26.7.
The shift direction is determined by two possible methods.