Editing Mastercam post processors allows you to customize G-code output to perfectly match your CNC machine’s requirements, reducing the need for risky manual code modifications. Safe Editing Practices
Always Create a Backup: Before making any changes, copy your original .pst file and store it in a safe location.
Use Proper Tools: While standard text editors work, Mastercam Code Expert is recommended for its built-in recognition of variables and operators.
Utilize the Debugger: Enable the debugger in Mastercam to step through the post-processing routine. This helps you identify exactly which part of the post processor code is generating specific lines of G-code. Common Customization Steps mastercam post processor editing
Open the File: Locate your post processor file (typically with a .pst extension) in the Shared Mastercam directory. Identify Modifications: Common edits include:
Tool Change Logic: Adjusting commands to match specific machine tool changer requirements.
Spindle & Coolant Control: Modifying M-codes (e.g., changing coolant start/stop timing). Editing Mastercam post processors allows you to customize
Custom Macros: Adding safety checks or proprietary machine functions.
Test with Simple Toolpaths: After saving changes, test the post on a simplified part with only one or two toolpaths to verify the output before running it on a machine. Advanced Support and Resources Mastercam Post Processor User Guide - CLaME
Problem: You want an M01 (Optional Stop) followed by a probe routine after every tool.
Solution: Edit the ptlchg$ section (tool change). Add: Always check your logic flow—don’t break the tool
"M01", e$
"(CHECK TOOL ", *t$, " FOR BREAKAGE)", e$
"M98 P8000", e$
Always check your logic flow—don’t break the tool change sequence.
If your machine uses custom M-codes for different tool types (e.g., M133 for live tooling), use a lookup table.
fstrsel sm06 toolchng mcode 6 -1
When you edit a post, it will likely break on the first run. Here is how to fix it without throwing your monitor out the window.