
B-63944EN-2/02 PROGRAMMING 5.FUNCTIONS TO SIMPLIFY PROGRAMMING
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5.1.12 Boring Cycle (G88)
This cycle is used to bore a hole.
Format
G88 X_ Y_ Z_ R_ P_ F_ K_ ;
X_ Y_ : Hole position data
Z_ : The distance from point R to the bottom of the hole
R_ : The distance from the initial level to point R level
P_ : Dwell time at the bottom of a hole
F_ : Cutting feed rate
K_ : Number of repeats (if required)
G88 (G98) G88 (G99)
Spindle CW
Initial level
Point R
Point Z
P
Spindle stop
after dwell
Spindle CW
Point R level
Point R
Point Z
P
Spindle stop
after dwell
Explanation
- Operations
After positioning along the X- and Y-axes, rapid traverse is performed
to point R. Boring is performed from point R to point Z.
When boring is completed, a dwell is performed at the bottom of the
hole, then the spindle is stopped and enters the hold state. At this
time, you can switch to the manual mode and move the tool manually.
Any manual operations are available; it is desirable to finally retract
the tool from the hole for safety, though.
At the restart of machining in the DNC operation or memory mode,
the tool returns to the initial level or point R level according to G98 or
G99 and the spindle rotates clockwise. Then, operation is restarted
according to the programmed commands in the next block.
- Spindle rotation
Before specifying G88, use an auxiliary function (M code) to rotate
the spindle.