B-63324EN/03 PROGRAMMING 13.FUNCTIONS TO SIMPLIFY PROGRAMMING
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13.1.4 Drilling Cycle, Spot Drilling (G81)
This cycle is used for normal drilling.
Cutting feed is performed to the bottom of the hole. The tool is then
retracted from the bottom of the hole in rapid traverse.
Format
G81(G98) G81(G99)
G81 X_ Y_ Z_ R_ F_ L_ ;
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
F_ : Cutting feedrate
L_ : Number of repeats (if required)
Initial level
Point R
Point Z
Point Z
Point R
Point R level
Explanation
- Operation
After positioning along the X- and Y-axes, rapid traverse is performed
to point R.
Drilling is performed from point R to point Z.
The tool is then retracted in rapid traverse.
- Spindle rotation
Before specifying G81, use a miscellaneous function (M code) to rotate
the spindle.
- Miscellaneous function
When the G81 command and an M code are specified in the same block,
the M code is executed at the time of the first positioning operation.
When L is used to specify the number of repeats, the M code is
performed for the first hole only; for the second and subsequent holes,
the M code is not executed.