Owner's manual

Milling Fixed Cycles
Chapter 26
26-32
The format for the G87 back boring cycle is:
G87X__Y__Z__{I__J__K__}R__F__L__;
Q__
Where : Is :
X,Y
specifieslocation ofthe hole.
Z
defines the Zpointlevel. The Z pointlevelin thiscase isthe top ofthe hole
that is beingcutbytheback boringoperation.
QorI,
J, K
defines the tool shiftamountand direction.
R
defines the positionbeyond the holebottomso the toolcan safelyshift.
F
defines the cutting feedrate.
L
defines the numberoftimesthe millingfixedcycle isrepeated.
(See section 26.3 for a detailed description of these parameters.)
Important: This cycle requires an existing hole through which the back
boring tool can be safely lowered prior to the back boring operation.
Figure 26.14
G87: Back Boring Cycle
Spindle
orientation
Hole bottom
Z point level
Spindle orientation
Spindle orientation forward
after returning to initial
point level
Initial point
level
C
u
t
t
i
n
g
f
e
e
d
Rapid feed
Spindle rotation forward
1
2
3
4
5
6
7
8
(G87): Back Boring Cycle