CNC Machinist Calculator UltraG99 Canned cycle return to R level / Feed per revolution
Fanuc G-code · Mill, Lathe
On mills: Canned cycle return to R level
After each hole the tool returns only to the R plane, saving time between holes when nothing is in the way.
Format
G99
How it works
Modal, group 10.
Example program
G43 H01 Z1. (INITIAL LEVEL)
G99 G81 X1. Y1. Z-.5 R.1 F8. (RETURN TO R.1)
X2. (NEXT HOLE AT R LEVEL)
G98 X3. (LAST HOLE, RETURN TO Z1.)
…
G99 G81 X1. Y1. Z-.5 R.1 F8. (RETURN TO R.1)
X2. (NEXT HOLE AT R LEVEL)
G98 X3. (LAST HOLE, RETURN TO Z1.)
…
The full 5-line example is in the app. Example is in inch. Check offsets and clearances first.
Watch out for
- Use G98 on the hole before a clamp or a step in the part.
- You can switch G98 and G99 on any hole line in the cycle.
On lathes: Feed per revolution
In G code system A, G99 makes F inches per spindle revolution. The normal mode for turning.
Format
G99
How it works
Modal, group 05. Power on default on most lathes, set by parameter.
Example program
G18 G40 G99 (SAFETY LINE, FEED PER REV)
G97 S1000 M03 (SPINDLE ON)
G00 X1.1 Z.1 (APPROACH)
G01 Z-1. F.008 (.008 INCH PER REV)
G97 S1000 M03 (SPINDLE ON)
G00 X1.1 Z.1 (APPROACH)
G01 Z-1. F.008 (.008 INCH PER REV)
Example is in inch. Check offsets and clearances first.
Watch out for
- With the spindle stopped, G99 feed moves will not move.
- Put G99 in the safety line at the top of each turning tool.
Related codes
G99 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Haas NGC | Canned cycle R plane return |
| Mazak (EIA) | Canned cycle return to R plane |
| Mitsubishi M70 M80 | Canned cycle return to R plane |
| Brother Speedio | Canned cycle return to R plane |
| Heidenhain TNC (ISO) | Tool definition in the program |
| Fagor 8055 8065 | Return to reference plane |
| LinuxCNC Tormach | Cycle retract to R plane |
| Mach3 Mach4 | Cycle return to R plane |
| Centroid CNC12 Acorn | Canned cycle return to R plane |
| Hurco WinMax (NC) | Cycle return to R plane |
| Fadal | Fixed cycle return to R0 plane |
| Swiss (Citizen Star) | Feed per revolution |
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