Mastercam Post language looks like a hybrid of C and BASIC from 1995. But the core rules are simple:
Including the tool name or operation name in the code.
Perform a dry run on the CNC machine (preferably with no tool or part) to ensure the motions are correct. Conclusion
: If your edits break the code, you must have a clean version to revert to immediately to avoid machine downtime. 2. Choosing the Right Editing Tools
Here are three real-world edits you might need tomorrow: mastercam post processor editing
An MP post processor file is organized into distinct, predictable sections. Modifying a post requires knowing exactly where these blocks reside. The Header Section
Ensure your custom blocks start with a lowercase "p" (e.g., pcustom_block ) and are defined on a fresh line without indentation. Indentation Rules
# CUSTOM EDIT: Changed from M08 to M88 for thru-spindle coolant on 2026-04-13 if coolant$ = 1, pbld, n$, "M88", e$ # Was M08
psof$ # Start of file for non-zero tool pbld, n$, "G00 G17 G40 G80 G90", e$ Mastercam Post language looks like a hybrid of
If you need help identifying which variables to change, please let me know: (Fanuc, Haas, etc.)
Add safety blocks, change M-code functionality, or add automatic tool length compensation.
The Ultimate Guide to Mastercam Post Processor Editing A Mastercam post processor is the critical bridge between your digital CAD/CAM design and your physical CNC machine. It translates Mastercam’s internal toolpath data (NCI files) into the specific G-code and M-code language that your machine tool controller understands.
What (e.g., Haas NextGen, FANUC 31i, Heidenhain) are you using? Conclusion : If your edits break the code,
psof : "Post Start of File." Triggers during the first tool change/operation. ptlchg : Triggers at every subsequent tool change.
Use # to comment on your changes so you know why you made them later.
These are the "subroutines" that Mastercam calls during posting:
Mastercam Post language looks like a hybrid of C and BASIC from 1995. But the core rules are simple:
Including the tool name or operation name in the code.
Perform a dry run on the CNC machine (preferably with no tool or part) to ensure the motions are correct. Conclusion
: If your edits break the code, you must have a clean version to revert to immediately to avoid machine downtime. 2. Choosing the Right Editing Tools
Here are three real-world edits you might need tomorrow:
An MP post processor file is organized into distinct, predictable sections. Modifying a post requires knowing exactly where these blocks reside. The Header Section
Ensure your custom blocks start with a lowercase "p" (e.g., pcustom_block ) and are defined on a fresh line without indentation. Indentation Rules
# CUSTOM EDIT: Changed from M08 to M88 for thru-spindle coolant on 2026-04-13 if coolant$ = 1, pbld, n$, "M88", e$ # Was M08
psof$ # Start of file for non-zero tool pbld, n$, "G00 G17 G40 G80 G90", e$
If you need help identifying which variables to change, please let me know: (Fanuc, Haas, etc.)
Add safety blocks, change M-code functionality, or add automatic tool length compensation.
The Ultimate Guide to Mastercam Post Processor Editing A Mastercam post processor is the critical bridge between your digital CAD/CAM design and your physical CNC machine. It translates Mastercam’s internal toolpath data (NCI files) into the specific G-code and M-code language that your machine tool controller understands.
What (e.g., Haas NextGen, FANUC 31i, Heidenhain) are you using?
psof : "Post Start of File." Triggers during the first tool change/operation. ptlchg : Triggers at every subsequent tool change.
Use # to comment on your changes so you know why you made them later.
These are the "subroutines" that Mastercam calls during posting:
Connect:
HBS Remote Support | Service & Technical Support | E-Bill Portal
Terms & Conditions PDF | Cookie Policy | Privacy Policy | Onboarding Form | End User Agreements | E-Bill FAQ | Site Map
©2025 Heartland Business Systems. All rights reserved.