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G91.1 Incremental arc centers
Mach3 Mach4 G-code · Mill
I J K in arcs are the distance from the arc start point to the center. This matches most posts.
Format
G91.1
Addresses
| Address | What it does |
|---|---|
G91.1 | No address words |
How it works
Modal, arc center group.
Example program
G0 G20 G90 G54 G17 G40 G49 G80 (SAFE START, INCH)
G91.1 (INCREMENTAL IJ)
T1 M6 (TOOL CHANGE)
G0 X3.0 Y0 (START)
…
G91.1 (INCREMENTAL IJ)
T1 M6 (TOOL CHANGE)
G0 X3.0 Y0 (START)
…
The full 7-line example is in the app. Example is in inch. Check offsets and clearances first.
Watch out for
- Put G91.1 in the post header so the configuration setting cannot change your arcs.
Related codes
G91.1 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| LinuxCNC Tormach | Incremental arc center mode |
| Fadal | High speed execution |
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