Mastercam Post Processor Editing [extra Quality]
If you’ve been in CNC machining for more than a week, you’ve likely heard the phrase: “It’s just a post thing.”
Setting up specific routines to allow for automatic tool changers or changing the way the tool description is output in comments.
Some common tasks that may require post processor editing include:
Never send edited G-code directly to a machine without verification. mastercam post processor editing
Mastercam post processors use a specific syntax for variable handling. Understanding the suffixes is critical.
pdrill$ # Canned Drill Cycle if mi6$ = 1, "G81", pfzout, pfrout, e$ # Output G81 for standard drilling else, "G83", pfzout, pfrout, "Q", "0.1", e$ # Output G83 with Q value for peck drilling
Post blocks (e.g., psof for start of file, ptlchg for tool change) determine what is output at specific times. You can add, remove, or reorder G-codes within these blocks. 4. Common Customizations If you’ve been in CNC machining for more
Defines the physical parameters of the machine (e.g., axis limits, travel, coolant options).
The post must decide between G02 (CW) and G03 (CCW). The variable gcode$ usually dictates the movement type.
You cannot output data that does not exist in the NCI. If Mastercam does not output a "Custom Parameter" to the NCI, the post processor cannot "invent" it without external lookups or user-defined variables. Understanding the suffixes is critical
Post blocks are the structural loops that trigger during specific toolpath events. They always begin in the first column (no indentation).
fs2 1 0.7 0.6 # Decimal, absolute, 7 places, 6 decimal positions fs2 2 0.4 0.3 # Decimal, absolute, 4 places, 3 decimal positions fmt "X" 2 xabs # Format X coordinate with format statement 2 fmt "Y" 2 yabs # Format Y coordinate with format statement 2 fmt "F" 1 feed # Format Feedrate with format statement 1 Use code with caution. 🛑 Step-by-Step Editing Workflow
: 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
: 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
