Types of 4-axis work in Mastercam
| Type | Post output |
|---|---|
| Rotary indexing (planes) | Rotate, clamp, 3-axis cutting |
| Axis substitution (wrapping) | Y replaced by rotary degrees: XZA motion |
| Multiaxis 4-axis toolpaths | Simultaneous XYZA with feed handling |
Machine definition setup
- Rotary axis component: axis (A or B), rotation direction, orientation.
- Continuous or limited travel, and whether rollover is used.
- Minimum and maximum limits, indexing increment for indexers.
Axis substitution example
(Engraving text around a 40 mm diameter)
G0 X10. A0.
G1 Z19.5 F200.
X12. A8.594 F400.
X14. A17.189
G0 Z25.With axis substitution, Mastercam converts a flat Y distance into rotary degrees on the chosen diameter; the post outputs A instead of Y.
Direction and clamping
The post decides between shortest path, signed direction or controller rollover, and inserts clamp and unclamp codes around indexing moves. For continuous motion, clamps stay off, and feed is output in the controller's expected mode (for example G93 inverse time).
Indexers
Some older rotary indexers are controlled by an M-code signal rather than a true CNC axis. The post can output the indexer's command format instead of A-axis coordinates.
Most 4-axis surprises come from the post and machine definition disagreeing about direction.
Mastercam 4-axis posts
See our CNC post processor development service and rotary table post development.