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G29 Return from reference point
Haas NGC G-code · Mill, Lathe
On mills: Return from reference point
Moves the axes to the intermediate point stored by the last G28, then on to the commanded point.
Format
G29 X Y Z
Addresses
| Address | What it does |
|---|---|
X Y Z | Final position after passing through the G28 intermediate point |
How it works
Non-modal, group 00.
Example program
G91 G28 Z0. (Z HOME, STORES THE INTERMEDIATE POINT)
G90 (ABSOLUTE)
G29 X2. Y1. Z.1 (RETURN THROUGH THE STORED POINT)
G90 (ABSOLUTE)
G29 X2. Y1. Z.1 (RETURN THROUGH THE STORED POINT)
Example is in inch. Check offsets and clearances first.
Watch out for
- G29 uses the intermediate point from the last G28 in this program. Make sure one was set.
- Most shops use plain G00 moves instead, which are easier to read.
On lathes: Return from reference point
Moves the axes to the G29 reference point saved by G28, then to the position given in the G29 block.
Format
G29 X Z
Addresses
| Address | What it does |
|---|---|
X Z | Final target position after passing the reference point |
How it works
Non-modal, group 00.
Example program
G28 U1. W1. (UP 1 INCH, THEN HOME, SAVES REFERENCE)
T0202 (NEXT TOOL)
G29 X1.5 Z.1 (BACK THROUGH REFERENCE TO NEW POSITION)
T0202 (NEXT TOOL)
G29 X1.5 Z.1 (BACK THROUGH REFERENCE TO NEW POSITION)
Example is in inch. Check offsets and clearances first.
Watch out for
- G29 goes through the point saved by the last G28. Check that path is clear.
- Most programmers use G53 and plain G00 moves instead.
Related codes
G29 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Fanuc | Return from reference position |
| Mitsubishi M70 M80 | Return from reference position |
| Brother Speedio | Return from reference point |
| Heidenhain TNC (ISO) | Last position becomes the pole |
| Centroid CNC12 Acorn | Return from reference point |
| Hurco WinMax (NC) | Return from reference point |
| Fadal | Return from zero |
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