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Fusion360 Post Processor for Mach3 with WCS Probing Support



Mach3 is a very popular controller software for hobby grade CNC machines. Whilst it is not as sophisticated as "industrial grade" software, it is very configurable and many useful add-ons have been written for it including probing support.

However, Fusion360, which is a powerful CAD/CAM software, has become very popular even amongst hobbyists as it is available for such use for free. Fusion360 contains within its CAM section, probing operations which can be used stand alone or at the start of machining operations to set up the WCS origins.

The standard Fusion360 Post Processor (PP) for Mach3 does not contain support for these probing routines and so these advanced features are not available to most Mach3 users.

mlm Solutions have enhanced the standard PP by adding support for these Fusion360 operations and have written the supporting macro for Mach3.


Fusion360 has multiple probing operations as follows:-

Fusion360 Probing Operations

The mlmSolutions extensions provide support for all of the above as well as the tolerances for positions and size along with the option to halt probing if out of tolerance.

In order to do this, the enhanced PP inserts into the G-Code output file, values which it gets from the Fusion360 configuration screens. Some of these are values entered by the user such as the clearance (approach) or the over-travel. Some others are automatic as Fusion is "model aware" and thus knows for instance if there are features to avoid.


The probing operation will take place on whatever WCS (G54,55...) has been selected on the SETUP/PostProcess tab. The WCS that is adjusted as a result of the probing operation depends upon what has been set on the PROBE WCS/ACTIONS tab when the probing operation was set up.

If the "Override Driving WCS" check box is not checked, the WCS that is updated will be the same as that in which the probing operation takes place. Otherwise it will be the WCS that is selected in the "WCS Override" box.

Background Reading

In order to more fully understand the scope of these probing operations, it is suggested that you look at the following Autodesk resources.


This code will work with any type of probe that is compatible with the Mach3 probe input. Please ensure that the "probe Active" LED on Mach's screen is activated by the probe before you attempt any probing operations.

Ensure that you have the correct value for the tool tip diameter in Mach3's tool table for your probe tool number (commonly 99) before probing.

How to Get It

I offer this code back to the community at no cost. You can download it here DOWNLOAD

If you find this code to be useful to you, and you would like to make a small donation to help fund future support, then you can do so via Paypal to martinlmarriott @

If you find any errors or have any suggestions for improvement then please contact me here so that I can incorporate the corrections or ideas for the benefit of everyone.

This download contains three files:-
"mach3mill+probe.cps" is the PP and should be copied into the folder (local or cloud based) where Fusion360 expects to find its post processors on your system. Of course, if you have made your own customisations to the post processor, then these will have to be incorporated into this new PP.

"M90010.m1s" is the macro code and should be placed within the "[Mach3 folder]/macros/[current_profile]" folder where [Mach3 folder] is the folder where Mach3 is installed on your system and [current_profile] is the name of your profile.

"Fusion360_Post_Processor_for_Mach3_with_WCS_Probing_Support.pdf" which is the documentation and should give all the details you need.

*** NOTE ***
It has been reported that there were problems when using the macro with a CS Labs CSMIO motion controller with Mach3 R3.043.066. Investigation showed that the problem was caused by the CSMIO (or more likely the plugin) that did not properly support the G31 command. In fact, the CSMIO didnít work when the G31 was in Gcode either.
The solution was found to be to install Mach3 R3.043.022


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