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G71 Bolt hole arc / OD and ID stock removal cycle
Haas NGC G-code · Mill, Lathe
On mills: Bolt hole arc
On a Haas mill G71 drills holes on part of a circle with a set angle between them, using the active canned cycle. Not the Fanuc lathe rough cycle.
Format
Addresses
| Address | What it does |
|---|---|
I | Radius of the arc |
J | Angle of the first hole from the X axis |
K | Angle between holes, sign gives direction |
L | Number of holes |
How it works
Non-modal, group 00. A canned cycle must be active.
Example program
G81 G98 Z-.5 R.1 F10. L0 (LOAD DRILL CYCLE, NO HOLE AT CENTER)
G71 I3. J10. K20. L4 (4 HOLES, 20 DEG APART, STARTING AT 10 DEG)
G80 (CANCEL)
Example is in inch. Check offsets and clearances first.
Watch out for
- Use L0 on the canned cycle line so no hole is drilled at the arc center.
On lathes: OD and ID stock removal cycle
Roughs along Z, pass after pass, down to a finish contour in blocks P to Q. Type I is used when X does not change direction. Type II allows pockets when the P block has both X and Z.
Format
Addresses
| Address | What it does |
|---|---|
P | Block number where the finish path starts |
Q | Block number where the finish path ends |
D | Depth of cut per pass, radius, positive |
U | X finish allowance, diameter, sign sets direction |
W | Z finish allowance |
I | X rough pass allowance, radius |
K | Z rough pass allowance |
F | Roughing feed rate |
S | Spindle speed for roughing |
T | Tool and offset for roughing |
How it works
Non-modal, group 00. G18 must be active.
Example program
G50 S3000 (LIMIT 3000 RPM)
G96 S500 M03 (CSS 500 SFM)
G00 G54 X2.1 Z.1 M08 (START POINT OUTSIDE STOCK)
…
The full 10-line example is in the app. Example is in inch. Check offsets and clearances first.
Watch out for
- If the P block has only X it is Type I. If it has X and Z it is Type II, even when Z does not move.
- U is negative for ID roughing, positive for OD.
- Z in the path must not change direction in either type.
- F, S and T inside P to Q are ignored while roughing and used later by G70.
Related codes
G71 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Fanuc | Stock removal in turning, rough cycle |
| Mazak (EIA) | OD and ID roughing cycle, Z direction |
| Okuma OSP | Return level for fixed cycles |
| Mitsubishi M70 M80 | Longitudinal rough cutting cycle |
| Siemens 840D 828D | Metric input for geometry |
| Heidenhain TNC (ISO) | Millimeter units |
| Fagor 8055 8065 | Millimeter programming |
| LinuxCNC Tormach | Lathe roughing cycle, along Z |
| Mach3 Mach4 | Metric units, Mach3 |
| Centroid CNC12 Acorn | Rough turning cycle |
| Hurco WinMax (NC) | Metric input (Basic NC) |
| Fadal | Check for metric setting, older code |
| Swiss (Citizen Star) | Rough turning cycle |
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