Mastercam Post Processor Editing Jun 2026

Change this: omitseq$ : no$ To this: omitseq$ : yes$

pheader$ : Outputs the program header, comments, and file metadata.

Create a simple file in Mastercam with common operations (Contour, Pocket, Drilling).

The editor allows you to browse through blocks, search for specific parameters, and test changes by posting sample toolpaths to verify the NC output. 3. Essential Post Processor Editing Techniques

Now go open that .pst file and make your machine sing. mastercam post processor editing

pwcs$ #G54+ coordinate setting if workofs$ <> 0, sav_absinc = absinc$, absinc$ = 0 "G", *workofs$ + 54, e$ absinc$ = sav_absinc

Most FANUC controls require M29 Sxxxx on a line before G84/G74 . A simple text edit won't work; you need logic. Inside the pdrill$ post block (for tapping cycles), add:

To edit these, change the integer value following the colon. Ensure you do not delete the variable name or the colon itself. 2. Customizing Post Blocks

Find the fs2 (Format Statement 2) definitions. Change this: omitseq$ : no$ To this: omitseq$

While minor edits (like changing a text string) are common for users, complex multi-axis posts (4-axis or 5-axis) often require expert intervention. Many shops work with their to develop custom posts, as errors in complex kinematic logic can lead to expensive machine damage.

use_rotm : 1 #Use rotary axis shortest direction?

While Mastercam comes with many standard post processors ( .pst and .psb files), these generic files often fail to utilize the unique capabilities of your specific CNC controller. Editing these files allows machinists and engineers to customize tool changes, optimize G-code formats, output specific macro calls, and eliminate repetitive, manual coding. 1. What is a Mastercam Post Processor?

A post-processor (often called a "post" or ".pst" file) is a specialized program within Mastercam that acts as a translator. It takes the generic toolpath data generated by Mastercam—such as linear moves, arcs, drilling cycles, and tool changes—and converts it into the specific G-code dialect required by your CNC controller (e.g., Fanuc, Haas, Siemens, Heidenhain). A simple text edit won't work; you need logic

After saving, post-process a simple toolpath in Mastercam and inspect the G-code to ensure the changes appear as expected. Some advanced users use debugging tools to step through the post logic line-by-line. Common Customizations

Before modifying any lines of code, you must understand the architecture of a Mastercam post processor. Modern Mastercam environments primarily use two types of post systems. MP Post Engine Architecture

Mastering Mastercam Post Processor Editing: A Comprehensive Guide