Safety
CNC Safety Disclaimer
Please read this before using any post-processor modifications from PostFix Pro.
Always verify before running production
Post-processor modifications directly affect CNC machine behaviour. An incorrect modification can cause tool crashes, damage to workpieces, machine components, or in serious cases, personal injury. Never run a modified post-processor on a live job without completing a dry run first.
What PostFix Pro is — and isn't
PostFix Pro is a software modification service. We analyse post-processor files against machine control documentation and suggest code changes to address the problem you describe.
PostFix Pro is not a machine programming service. We do not operate CNC machines, we do not have access to your machine, and we cannot test any output on your hardware.
PostFix Pro is not a substitute for trained CNC operator judgment. The operator and shop are solely responsible for safe machine operation.
Required verification steps
Before running any job using a modified post-processor, you must complete the following steps:
Review the diff
Read every change shown on the results page. Understand what was changed and why before loading the file onto your machine.
Simulate in your CAM software
Run a backplot and toolpath verification in Mastercam, Fusion 360, or equivalent before posting to the machine.
Single-block dry run (no material)
Load the modified post on your machine. Set Feed Hold and Single Block on. Run the program with no material or tooling, verifying each rapid and feed move is correct.
Check coolant codes manually
Verify that the correct coolant M-code activates for each operation. Incorrect coolant can damage tooling and workpieces.
Check tool change sequence
Verify that tool changes include a proper Z-retract before the T## M06 block. A missing retract at the wrong Z-position causes crashes.
Verify work offsets
Confirm the work offset (G54, G55, etc.) matches your fixture setup. An incorrect offset will drive the tool into the wrong position.
Check rapid moves
Step through all G00 rapid moves in single-block mode. Verify the machine moves to the expected position before clearing any rapid travel.
Specific risks of incorrect post-processor output
Post-processor errors can cause the following machine hazards:
Tool crashes
Incorrect rapid moves or missing retracts at tool changes
Workpiece damage
Wrong feedrate, depth, or canned cycle parameters
Wrong coolant activation
Flood where mist is required, or no coolant on deep drilling
Spindle direction errors
M03 vs M04 in the wrong orientation for certain tools
Work offset mistakes
G54–G59 mismatch can drive the spindle into fixtures or vices
Arc format errors
IJ vs R arc format mismatch can produce incorrect arc paths
Canned cycle issues
Incorrect G81/G83 parameters can result in wrong hole depths
File format rejection
Control may reject the file entirely, requiring manual correction
Operator responsibility
The machine operator is solely responsible for the safe operation of the CNC machine. By using output from PostFix Pro, the operator accepts responsibility for verifying that the modified post-processor produces safe, correct machine behaviour before any production use.
PostFix Pro's liability is limited to the amount paid for the fix request. See our Terms of Service for the full limitation of liability clause.
Questions?
If you're unsure about any modification in the fix we've provided, do not run it. Contact us at support@cncpostfix.ai and we'll explain the change in plain language before you run anything.