PowerMill installs a set of standard 3-axis post processors locally by default. These are "free" as they are included with your installation. Autodesk Community, Autodesk Forums, Autodesk Forum Default File Location:

Searching for a "free download" often leads to generic files that cause more headaches than they solve. A post processor isn't a universal plugin; it is a set of logic rules tailored to a specific machine kinematics and controller combination.

Autodesk PowerMill 2020 is a powerful CAM (Computer-Aided Manufacturing) software used for generating G-code for CNC (Computer Numerical Control) machines. One of the essential components of PowerMill is the post processor, which plays a crucial role in converting the toolpath data into a format that can be understood by the CNC machine.