Four levels of validation
| Level | What it checks |
|---|---|
| 1. Output review | Syntax, format, codes and structure against the specification |
| 2. Machine simulation | Motion, limits, collisions and kinematics using G-code |
| 3. Machine dry run | Real controller behaviour without cutting |
| 4. First-part proving | Accuracy, surface and cycle time on real material |
Build a test part set
Create CAM files that exercise every feature the post supports:
- Facing, 2D contour with cutter compensation, pocketing, 3D surfacing.
- Arcs in G17, G18 and G19 planes, helical entries.
- Drilling, peck drilling, tapping (rigid and floating), boring.
- Multiple work offsets and multiple setups.
- 4th-axis indexing and wrapping, 3+2 and simultaneous 5-axis.
- Turning, grooving, threading, C-axis and live tooling where relevant.
- Edge cases: very small arcs, rotary limits, long programs.
Output review checklist
[ ] Header and safe start block correct
[ ] Tool change sequence and pre-select correct
[ ] G43 / H values match tool numbers
[ ] Work offsets as programmed
[ ] Arc output valid in all planes
[ ] Cycles use correct parameters and retract mode
[ ] Rotary directions and limits respected
[ ] Coolant and spindle codes correct
[ ] End of program returns to safe positionMachine simulation
Simulate the posted G-code, not the CAM toolpath, on an accurate machine model. Tools such as VERICUT, NCSIMUL, NX ISV (CSE), CAMplete and Fusion machine simulation reveal over-travel, collisions with fixtures and wrong rotary solutions.
Machine proving
- Raise work offset Z (or run above the part) for an air cut.
- Reduce rapid and feed overrides.
- Use single block through tool changes, rotary moves and cycles.
- Cut a test part in easy material, then a production part.
Regression testing
Every time the post changes, re-post the whole test set and compare output with the last approved version using a file comparison tool. Any unexpected difference is investigated before release.
Test the post once thoroughly, and every program after it benefits.
Professional post testing
See our CNC post processor development service and verification before running on a machine.