Powermill Macro

A successful macro isn't just code; it's a user experience. Here are three "must-have" macros for any PowerMill programmer.

PowerMill often writes errors to a log file (usually in C:\Users\[Name]\AppData\Local\Autodesk\power mill...\Log). When a macro does nothing, check the log.

At its core, a PowerMill macro is a simple text file (with a .mac extension) containing a list of PowerMill commands. When you "run" the macro, PowerMill executes each command in sequence—exactly as if you typed them into the command line yourself.

Think of it as a recipe. Once you prove it works, you can use it over and over without thinking about the individual steps.

Let’s build a macro that automates the safe setup of a new job. Open Notepad++ (or the built-in PowerMill Editor) and follow along. powermill macro

Step 1: The Header (Safety checks) Always start with clearing the slate to avoid variable conflicts.

// Stop on un-recoverable errors
MACRO ABORT ON
// Clear the session (Optional: Use with caution)
DELETE TOOLPATH ALL
DELETE TOOL ALL
DELETE MODEL ALL

Step 2: User Input (Parameters) Hard-coded macros are brittle. Use INPUT or QUERY to ask the user for variables.

STRING tool_diameter = INPUT "Enter Tool Diameter"
STRING stock_height = INPUT "Enter Stock Z Height"

Step 3: The Logic Now, execute the commands using the variables.

CREATE TOOL "Endmill" dia $tool_diameter  // The $ recalls the variable
ACTIVATE TOOL "Endmill"
CREATE STOCK BOX
EDIT STOCK BOX LIMITS -10 -10 0 10 10 $stock_height
 A successful macro isn't just code; it's a user experience

Step 4: Save and Run Save the file as Setup_Macro.mac. In PowerMill, go to Macro > Play or drag and drop the file into the graphics window.

Hard-coded macros work, but parameterized macros are reusable. Use INPUT to ask the user for values.

Example: Parameterized Rest Roughing Macro Step 2: User Input (Parameters) Hard-coded macros are

// Ask the user for key values
INPUT T "Enter Tool Diameter (mm):" dia
INPUT T "Enter Stepover (%):" step
// Apply those values
CREATE TOOL ; "Tool" BALLMILL
EDIT TOOL "Tool" DIAMETER $dia
EDIT TOOLPATH REST ROUGH_STEPOVER $step
CALCULATE

The $dia and $step variables insert whatever the user typed. One macro, infinite variations.