Mach3 goodies

Thursday, 08 February 2024

Fusion post processor
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Inspection probing
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ATC controller
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Mach3 goodies

The downloads on this page are designed to provide the same probing and ETS functions as the PathPilot versions.  They provide support for all the programmable probing options in Fusion360 and also the added ability to use an electronic tool setter (ETS) to set tool lengths during program runs and also to check for tool breakage after each operation.

There are 3 separate files required.  The download links are as follows and the functions provided by each file are described below.

File Description
M200.mcc Implements a set of functions 'M200 P1'.. 'M200 P19'.  These are the support functions required to perform the Fusion 360 WCS probing operations
M201.mcc To support the ETS extensions for Fusion 360, this macro file adds 'M201 P1' .. 'M201 P4'
mach3mill.cps The modified Fusion 360 post processor.



There's a general problem with Mach 3 in that values entered into DROs don't have their units converted between mm and inches when the machine changes from G21 to G22 and back. If you use an ethernet smoothstepper, then you'll be familiar with the problem.  Homing speeds and accelerations don't get converted, so if you set up speeds in mm/min and then execute G20 before referencing the axes, you'll see your axes attempt to find home at 25.4 times the intended speed.

There are a number of parameters required to configure the operation of the probing routines and they have the same problem.  For this reason, it's best to decide what units you're going to use, configure the machine like that and then stick to it.  Fusion 360 can output in either mm or inch no matter what the drawing units are, so this shouldn't be a problem.  I've always used mm on my mill, so that's what I'd recommend.

The following table lists values that must be entered by the user and the DRO numbers.  If you can edit your screen set, then you may add these values.  If not, then the DRO numbers are the same as are used by the excellent 'ProbeIt' wizard, so you can use that wizard to enter the value.  Equally, if you already use ProbeIt, then you'll already have configured these values, so no additional configuration is required.  You can find ProbeIt on the Wizards menu in any standard Mach3 installation.

DRO number ProbeIt parameter name Function Suggested value
1821 Init feed Fast probe speed.  The feed rate used for the first, rough probe 750 mm/min
1822 Slow Feed Slow probe speed.  Feed rate used for the final, max resolution probe 25 mm/min
1823 Max probe distance Max probe distance.  Max distance to probe whilst looking for the initial contact.  This affects the M201 ETS functions only.  The Fusion360 operations all provide their own values for this via the Approach and Over-travel parameters of the probing operations. 30mm
1824 Slow clear This is the distance the probe retracts after making the initial, rough probe before starting the final, slow probe operation. 1mm
1829 Avg probe diameter Probe diameter.  This is not the nominal diameter of the probe tip that you would measure with a micrometer.  The value here is corrected for the inevitable flex in the probe stylus and will therefore typically be smaller than nominal.

The best way to measure it is with a gauge ring and use the calibrate function in ProbeIt.  You can alternatively use ProbeIt to measure the thickness of a known block of material - a gauge block would be best - and then alter the nominal diameter until you measure the correct block width.  Be sure to check this at different probe orientations as the effective diameter will change as the spindle is rotated and it's important to get a good average value.

For the Tormach passive probe with a 50mm long stylus with a 3mm diameter tip, I generally measure this value to be around 2.85mm


Fusion 360 ETS operations

To use the Fusion 360 integrated ETS funcitons, you must set WCS 6 (G59) to have its xy origin located at centre of the ETS and the z origin located at the ETS trigger point.  The xy origin can be set by eye, but to set the z accurately, position a tool of known length above the ETS and type M201 P2 into the DRO.  The machine will probe downward until it finds the contact and adjusts the WCS z-offset to define that location as z = 0.

If your z-axis is referenced using simple microswitches, you will have to repeat this process every time you reference the machine in order to get accurate results from the ETS.

Fusion 360 Probing operations

Apart from filling in the values noted above for ProbeIt, there's no additional setup required for Fusion360.  If you can use the basic xy probing functions in ProbeIt, then the FUsion360 ones should just work.

M200 Probing functions

The functions supported by the M200 macro file require a number of parameters to be passed via g-code variables #1000 through #1017.  as a result, the M200 functions are too complicated to use via any other route.

M201 ETS functions

Unlike the M200 functions, the M201 functions that support the ETS ops are very simple and can be used from the MDI command line.

Command Operation
M201 P1 Perform 2 stage probe vertically down (max distance governed by DRO 1823 (ProbeIt parameter Max probe distance).  Display the result in the status line.  If you have voice output enabled in your Mach 3 settings, then the result will be read.
M201 P2 Similar to M201 P1 except that the current WCS z-offset will be modified so that the probe result point becomes z=0.
M201 P3 Again similar to M201 P1, but this time the tool length is adjusted so the point found by the probe is z=0.
M201 P4 Qtol Runs M201 P1 but then aborts the running program if the result was outside the range -tol <= z <= tol


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This site was last updated 07/09/20