Lathe fundamentals in the post
| Topic | Typical output (FANUC-type) |
|---|---|
| Diameter programming | X values are diameters |
| Tool call with offset | T0303 (tool 3, offset 3) |
| Constant surface speed with limit | G50 S3000 then G96 S220 M03 |
| Feed per revolution | G99 (G-code system A) or G95 |
| Rough / finish cycles | G71 / G70 |
| Threading | G76 or G32 |
| Grooving / peck | G75 / G74 |
G-code system A, B or C changes some codes (for example feed per rev and absolute/incremental), so the post must match the machine's setting.
Example: rough and finish with cycles
T0101 (OD ROUGH)
G50 S3000
G96 S220 M03
G00 X62. Z2. M08
G71 U2. R0.5
G71 P100 Q200 U0.4 W0.1 F0.25
N100 G00 X30.
G01 Z-20. F0.15
X50. Z-30.
Z-50.
N200 X62.
G70 P100 Q200
G28 U0. W0.Cycles or expanded code?
Controller cycles make programs short and editable at the machine. Expanded code gives CAM full control of every pass. Many shops prefer cycles for simple profiles and expanded output for complex ones; the post can support both via a property.
Other lathe features
- Bar feeder, part catcher and chuck codes.
- Tailstock control.
- Tool nose radius compensation (
G41/G42). - Safe index positions for the turret.
Lathe posts are short in code but full of machine-specific detail.
Lathe post development
See our CNC post processor development service and C-axis lathe posts.