Defining the machine
In Mastercam, the machine definition describes the rotary axes (head or table), their order, rotation directions and limits. The post reads this and computes rotary positions for each tool vector.
Output modes
| Mode | When to use | Example |
|---|---|---|
| 3+2 with tilted plane | Positional machining; controller handles the plane | FANUC G68.2, Siemens CYCLE800 |
| 3+2 with rotated coordinates | Controller has no tilted plane function | Post outputs rotated XYZ |
| Simultaneous with TCP | Controller supports TCP | FANUC G43.4, Heidenhain M128 |
| Simultaneous without TCP | No TCP option | Post calculates pivot-compensated positions |
Example: FANUC TCP output
T12 M6
G0 G90 G54 A0. C0.
G43.4 H12
G0 X15. Y-10. Z50. A-20. C35.
G1 Z5. F1500.
X18.2 Y-8.7 Z4.1 A-21.5 C37.2 F1200.
...
G49Rotary solutions and limits
- Prefer the solution that keeps the tilt axis within its best range.
- Detect limit violations and output retract, rewind and re-engage.
- Manage C-axis rollover to avoid unnecessary full rotations.
- Control motion near the singularity (tool vertical on table-table machines).
Simulation
Mastercam machine simulation checks the toolpath against the machine model, and G-code simulation (for example VERICUT) verifies the actual posted output. For 5-axis production, both are recommended.
Rotary solutions and limits are where 5-axis posts succeed or fail.
Mastercam 5-axis posts
See our CNC post processor development service and rotary limits and rewind logic.