Mastercam Post Processor Editing Info
Accessed via File → Edit → Post Processor. It provides syntax highlighting and basic error checking. It is fine for small edits, but it crashes frequently with large files.
Mastercam Post Processor editing is not a "set it and forget it" task. Every time you update Mastercam to a new version (2024 to 2025), the MP language changes slightly. Every time you buy a new probe or a new bar feeder, you will have to tweak your post.
The power of editing your own post is that you eliminate manual G-code editing. No more sitting at the control typing in G10 L2 P1... because the post forgot it. No more "find and replace" for coolant commands.
Start small. Back up your files. Change the coolant command. Test it on a piece of foam. Then move on to work offsets. Eventually, you will realize that the post processor is not a "black box," but a powerful, programmable tool that customizes Mastercam to fit your machines perfectly.
Remember: The best post processor is invisible. You generate the code, press cycle start, and walk away. If you have to touch the G-code, you need to edit your post.
Now go open that .pst file and make your machine sing.
Mastercam Post Processor Editing: A Practical Guide A Mastercam post processor is the essential "interpreter" that translates your digital toolpaths into the specific G-code dialect your CNC machine understands. While stock post processors are often sufficient, customizing them can significantly improve efficiency, reduce manual G-code editing, and unlock machine-specific features. 1. Preparation and Safety
Before making any changes to a post processor file, follow these non-negotiable safety steps: Create a Backup : Always copy your existing
file to a secure location before editing. If an edit fails, you must be able to revert to a working version. Use the Right Editor : Mastercam includes Code Expert
, which provides syntax highlighting specifically for the MP (Mastercam Post) language.
: If you are sending your post to a reseller for professional editing, use the
utility to package your machine definition, control definition, and post file together. 2. Common Editing Methods
Depending on the complexity of your needs, there are three primary ways to modify how Mastercam outputs code: Post Switches
Many post processors include a "switch" section at the top of the file. These are simple variables (usually
) that toggle features on or off without requiring complex programming.
: Enabling/disabling stage tool changes, toggling between IJK and R for circular interpolation, or turning off line numbers (N-numbers). The Mastercam MP Language
For deeper customization, you must edit the logic within the file using Mastercam’s proprietary MP scripting language. Mastercam Post Processor User Guide - CLaME
Mastercam Post Processor Editing: A Comprehensive Guide
Mastercam is a popular computer-aided manufacturing (CAM) software used by machinists and manufacturers to create and optimize G-code for CNC machines. One of the key components of Mastercam is the post processor, which plays a crucial role in converting the CAM software's output into a format that can be read by the CNC machine. In this article, we will explore the world of Mastercam post processor editing, including its importance, basic concepts, and step-by-step editing techniques.
Why Edit Mastercam Post Processors?
Post processors are essentially translators that convert Mastercam's output into a specific CNC machine's language. While Mastercam provides a range of built-in post processors for various CNC machines, there may be instances where a custom post processor is required. This could be due to:
Basic Concepts of Mastercam Post Processors
Before diving into post processor editing, it's essential to understand the basic concepts: mastercam post processor editing
Step-by-Step Guide to Editing Mastercam Post Processors
Editing a Mastercam post processor requires a basic understanding of programming concepts and the post processor syntax. Here are the general steps:
Common Post Processor Editing Tasks
Some common tasks that may require post processor editing include:
Best Practices and Tips
When editing Mastercam post processors, keep the following best practices and tips in mind:
In conclusion, Mastercam post processor editing is a powerful way to customize and optimize the output of your CAM software. With a basic understanding of post processor concepts and syntax, users can make targeted changes to improve the machining process. By following best practices and tips, users can ensure that their edited post processors produce accurate and efficient G-code for their CNC machines.
In the world of CNC programming, the Mastercam Post Processor
is the vital bridge between a digital toolpath and the physical machine. It translates generic CAM data into the specific G-code "language" a machine controller understands. For many programmers, learning to edit these files is the "rite of passage" that separates a basic user from a master. eMastercam.com Why Edit a Post?
While Mastercam offers thousands of off-the-shelf posts, customization is often necessary to:
A frequent annoyance is improper formatting (e.g., X1.234567 instead of X1.234). This is defined in the Format Definition section, usually denoted by fs$.
The Problem: Your Haas machine uses M08 for flood coolant, but your post outputs M07 (mist).
The Solution: Locate the scoolant string definitions.
Original:
scoolant : "M07" #Flood
Edited:
scoolant : "M08" #Flood
Editing Mastercam post processors is a targeted, technical task that adapts CAM output to machine-specific requirements. Follow a disciplined workflow: backup, small iterative edits, thorough simulation, and controlled on-machine testing. Properly managed posts reduce machining errors, improve cycle reliability, and standardize shop practices.
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In Mastercam, post processor editing is the process of customizing the script that translates CAM toolpath data into machine-specific G-code for a CNC machine. This ensures the output is perfectly compatible with a specific machine controller's requirements, such as including custom tool tables or specific canned cycles. New York University Key Components of a Post
A complete "post" typically consists of three primary files:
: The main script containing the logic for G-code generation. Machine Definition : Defines the physical parameters and axes of the machine. Control Definition
: Sets the rules for how the controller interprets code, such as arc formatting or drilling cycles. support.qtemfg.com How to Edit Mastercam Posts
You can modify these files using several different tools depending on your technical comfort level: Mastercam Code Expert Accessed via File → Edit → Post Processor
: The built-in editor specifically designed for viewing and editing Post Developer Kit (PDK)
: A dedicated professional toolset provided by Mastercam for creating and managing advanced post processors. External Text Editors : You can use editors like Visual Studio Code
for manual script editing, provided the file is not encrypted (non- Machine/Control Definition Manager
: Accessible directly within Mastercam for adjusting settings without manual coding. New York University Common Customizations Tool Tables
: Modifying the post to automatically pull tool names or bin locations into the header of the G-code. Custom M-Codes
: Adding machine-specific commands like air blasts (e.g., M83) or coolant triggers. Axis Rotation
: Adjusting the post to support multi-axis movements like 3+2 or full 5-axis simultaneous motion.
For complex edits, Mastercam provides official guides through their Help files and community support on forums like New York University Are you looking to make a specific change
to your G-code output, such as adding a custom header or changing how tool changes are handled? Mastercam Post Processor User Guide - CLaME
Mastercam Post Processor Editing: A Guide to Customizing G-Code
In Mastercam, a post processor acts as a translator, converting the generic toolpath data from your CAM software into machine-specific G-code that your CNC controller understands. While Mastercam offers thousands of ready-to-use posts, manual editing is often required to fine-tune machine behavior, automate safety retracts, or integrate custom macro logic. The Core Components of a Mastercam Post
A functional "post" in Mastercam isn't just one file; it is typically comprised of three essential elements:
Machine Definition (.mcam-control): Defines physical machine attributes like travel limits and axis orientation.
Control Definition (.mcam-mmd): Specifies the formatting of the G-code, such as arc support and decimal precision.
PST File (.pst): The primary script file containing the logic and formatting rules for G-code output.
PSB File (.psb): Some custom or advanced posts include an encrypted "binary" file that contains protected logic you cannot edit directly. How to Edit a Post Processor
Editing a post is essentially a scripting task. You can modify these files using any text editor, though many developers use specialized editors like Mastercam Code Expert or CIMCO Edit for syntax highlighting.
Locate the File: Post files are usually found in the C:\Users\Public\Documents\shared Mastercam 20xx\Posts directory.
Backup Your Post: Always create a copy of your .pst file before making changes. One misplaced character can cause machine crashes or output errors.
Open and Search: Open the .pst file in your editor. Most edits involve searching for "post blocks" (sections starting with p) such as: pheader: Controls the very beginning of the G-code program. psof: "Start of file" logic for the first tool change. ptlchg: Logic used for subsequent tool changes. peof: "End of file" commands like parking the machine.
Test and Debug: 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
Safety Lines: Adding or removing specific G-codes (like G21 for metric or G91 G28 Z0 for homing) at the start of a program. Basic Concepts of Mastercam Post Processors Before diving
Coolant Codes: Changing how and when M08 (flood) or M07 (mist) are triggered.
Custom Macros: Integrating advanced automation like tool life management or probing cycles directly into the posted code.
Comments: Formatting how tool names and operation notes appear in the G-code for the operator. Professional Support vs. DIY
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 Mastercam Reseller to develop custom posts, as errors in complex kinematic logic can lead to expensive machine damage.
For those looking to master this skill, specialized training programs cover Fanuc, Haas, and Siemens logic, teaching users how to build IF/WHILE loops and math-driven cycles into their posts.
Mastercam post processors serve as the vital bridge between your CAM software and your CNC machine's controller. While the default posts provided with the software cover a wide range of machines, high-level manufacturing often requires fine-tuning to optimize cycle times, ensure safety, and leverage specific machine features. Mastering the art of post processor editing allows you to automate manual G-code edits, reducing the risk of human error on the shop floor. The Architecture of a Post Processor
Before diving into edits, it is essential to understand that most Mastercam posts use the MP language. A standard post consists of several key sections:
Variable Definitions: This is where you initialize the data holders for coordinates, feed rates, and logic switches.Formatting Statements: These lines dictate how numbers appear in the G-code, such as the number of decimal places or the inclusion of leading/trailing zeros.Predefined Blocks: These are the "events" in the code, such as the start of a file, a tool change, or the end of a program.Lookup Tables: These maps correlate Mastercam internal values to specific machine G and M codes. Setting Up Your Environment
To edit a post safely, never work on your primary file. Create a backup copy of the .PST and .MCPOST files. Use a dedicated editor like Code Expert, which comes bundled with Mastercam. It offers syntax highlighting and "jump to" features that make navigating thousands of lines of code significantly easier. Common Post Modifications
Customizing Tool Change SequencesOne of the most frequent requests is modifying how a machine behaves during a tool change. You can edit the "ptlchg$" block to include specific safety moves, such as sending the Z-axis to a home position before the tool carousel rotates. You can also add logic to suppress redundant tool calls if the same tool is used in consecutive operations.
Adding Manual Entry and CommentsCommunication between the programmer and the operator is critical. By editing the post to automatically output tool descriptions, programmed feed rates, or custom operator notes at the beginning of each tool section, you create a more transparent workflow. This is typically handled in the "pheader " sections.
Managing Coolant CodesModern machines often have multiple coolant options: flood, mist, through-spindle, or high-pressure air. If your post only outputs M08, you can modify the coolant logic to recognize Mastercam's X-style coolant commands, ensuring the right M-code is paired with the right operation every time.
Adjusting High-Speed Machining ModesFor mold and die work, specific G-codes like G05.1 (Fanuc) or COMPCAD (Siemens) are required for high-speed look-ahead. You can hard-code these into the start-of-operation blocks so they activate automatically when a high-speed toolpath is detected, ensuring the machine doesn't "shudder" during complex 3D moves. Debugging and Testing
Once you have made your changes, the testing phase must be rigorous. Use the "Debug" mode in Mastercam to step through the post line-by-line. This tool shows you exactly which line of the post processor generated a specific line of G-code.
Always run the resulting code through a simulation software or a "dry run" on the machine with the feed rate turned down and no part in the vise. Verify that every tool change, spindle start, and rapid move matches your intent. Conclusion
Post processor editing is a transition from being a software user to a process architect. By investing time into the MP language, you eliminate the need for "hand-coding" at the machine, create safer programs, and ultimately get the most out of your CNC investment. Small logic changes today can save hundreds of hours of manual editing over the course of a production year.
Mastercam Post language looks like a hybrid of C and BASIC from 1995. But the core rules are simple:
Invest 10 hours in the Mastercam Post Processor Guide (PDF included in your install folder). Download the free MP Documentation from the official Mastercam forum.
Here are three real-world edits you might need tomorrow:
In the world of Computer-Aided Manufacturing (CAM), Mastercam holds a throne. It allows machinists and engineers to create complex toolpaths with a few mouse clicks. However, the toolpath inside Mastercam is just a ghost. It is a theoretical set of instructions that exists purely in the digital realm.
To make that ghost cut metal, you need a translator. That translator is the Post Processor.
Out of the box, Mastercam comes with generic post processors (MPFAN, MPLFAN, etc.). These are fantastic for general use, but they are precisely that: generic. If you run a Haas VF-2 with a 4th axis rotary, a laser cutter, a waterjet, or a Okuma Multus B-axis lathe, the generic post will fail. It might output the wrong G-code, ignore your coolant commands, or, worst of all, crash your spindle.
This is why Mastercam Post Processor Editing is the single most valuable skill for a serious CAM programmer. This article will serve as your deep-dive guide into understanding, editing, and mastering the .pst and .psb files that drive your shop.