GRBL Multi-Axis Post Processor

[tsmarks]

I am piecing together a post processor script for multi-axis GRBL machines.  (i.e. Arduino Mega with a 6 Axis)  I have successfully tested the 4th axis function.  With my limited experience, I think it works flawlessly.  

I would like to give back to the community by sharing the script. (attached below) And, I would like some feedback/testing.  If you have a multi-axis GRBL machine, give it a try and let me know what works or doesn't.

[tsmarks]

I guess I should give a little details on the multi-axis setup.

if you want to add the 5th axis you need to add follow this the B/C axis definition:  How to set up a 4/5 axis machine configuration in Fusion 360 and HSM CAM Post Processors 

In order to get the new Multi-Axis Rotary to work you need to set a High Feedrate: How to change the High Feedrate Mode in Fusion 360 CAM / HSM 

And make sure your machine setup has the same Axis configuration as you put in the post.  So if you add a B Axis in the Machine config oriented in the Y axis, make the line in the post match.  

[Anonymous]

Thank you for this. As I put my Mega/Ramps 1.4 together it dawned on me that the grbl post I use now probably wasn't going to work. Luckily I found your post. 

[ethier.jeanpierre]

Hi there!

I have just downloaded  the multi axis cps and looking forward to try it out!, i will  give you feedback on this  cause i am also using mega5x with a ramps board and i want to get into   rotary  milling for machining Wood for now!

Anyway  Thank you for sharing this!

Cheers!

[joch4VULR]

Works well, using 4 axis (b)

thank you

[Anonymous]

tsmarks thank you very much for your effort!

I have recently completed my 5axis machine with a mach3 controller and was able to write good g-code with Fusion 360.

My next step will be to test ramps 1.4 with GRBL mega 5x and your post processor. (I think it needs some tuning from a first look at function onOpen() similar to what I did in mach3mill.cps)

Please check my instructable here: https://www.instructables.com/id/DIY-Desktop-5-axis-CNC-Mill/

and let me know your thoughts.

Great job! Thank you!

[Anonymous]

i am test 3+2，look good!

thank you

[pmorenod]

Hi, im just making a new project of 5th axis MPCNC (PocketNC) style (images link below). So i will use ramps 1.4 with mega, im wondering about the changes i should make to this post processor that you make for grbl to set it up for my CNC. Also for the people that you could use it on a 3+2 cnc or 4th axis what toolpath could you do?

If someone is interested on the entire design of my cnc, tell me.

[Anonymous]

hi,

did you just upgrade your machine to ramps1.4 + arduino? .. i just have an machine on this setup with the same build style like yours.. but need an postprocessor für my grbl-mega-5x software to run my 5.axis build =/ 

[tsmarks]

I use a grbl compiled to work with my board by The Eccentric Workshop. But
any grbl complaint firmware should work with this postprocessor. I have
used it on different firmwares testing the bCNC update for 6 axis support.

[Anonymous]

i just tried a simple 4-axis toolpath and got this message:

Information: Configuration: Grbl 6 Axis

Information: Vendor: grbl

Information: Posting intermediate data to '/Users/Andy/Fusion 360 CAM/nc/1001.nc'

Error: Failed to post process. See below for details.

...

Loading locale from '/Users/Andy/Library/Application Support/Autodesk/webdeploy/production/380d70885f263236bcd663557495fe325106a36d/Autodesk Fusion 360.app/Contents/Libraries/Applications/CAM360/Data/Translations/german_de.xml'

Start time: Thu Dec 17 09:10:26 2020

Post processor engine: 4.5729.0

Configuration path: /Users/Andy/Library/Application Support/Autodesk/Autodesk Fusion 360/Y7ECKJPG6XA2/W.login/M/D20181030157539156/CAMPosts/grbl6axis.cps

Include paths: /Users/Andy/Library/Application Support/Autodesk/Autodesk Fusion 360/Y7ECKJPG6XA2/W.login/M/D20181030157539156/CAMPosts

Configuration modification date: Wed Dec 16 23:05:33 2020

Output path: /Users/Andy/Fusion 360 CAM/nc/1001.nc

Checksum of intermediate NC data: e3dd9446ed578822cce942b123aae895

Checksum of configuration: 4193eb8cb13ea73def20d16ea08909d3

Vendor url: https://github.com/grbl/grbl/wiki

Legal: Copyright (C) 2012-2019 by Autodesk, Inc.

Generiert von: Fusion 360 CAM 2.0.9512

...

Fehler: Failed to invoke function 'onOpen'.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Fehler: Failed to invoke 'onOpen' in the post configuration.

Fehler: Failed to execute configuration.

Stop time: Thu Dec 17 09:10:26 2020

Post processing failed.

[sa_sa_go]

Hello!

I am trying to use your postprocessor but I am getting an error when using rotary operation.

###############################################################################

Error: Feedrate is less than or equal to 0.

Error at line: 737

Error in operation: 'Rotary1'

Failed while processing onRapid5D() for record 361.

###############################################################################

Have you got any issue like this? Any solution?

[tsmarks]

I have had that error too.  The fix is: On the 'Linking' tab of the Rotary change the 'High Feedrate Mode' to 'Always use high feedrate'.  I am assuming lots of math and code could fix the problem correctly, but this works. 🙂

[sa_sa_go]

Thanks, that did the job!

[sa_sa_go]

Hello! I suspended my work for a few months and I am starting again, I remember the postprocessor working fine last time I used it, now I am getting this message:

Error: Error: Direction is not supported for machine configuration.

Error at line: 1

Do you happened to have the same issue?

[ethier.jeanpierre]

I have not used the multi axis post processor lately! sorry!
jp

[engineguy]

@sa_sa_go 

It is likely that your Post Processor has been updated automatically if you have not turned that facility off within your Preferences so any edits that may have been made to your original PP will have been overwritten, a tip, always keep your Post Processor in your Local/Personal or Cloud Libraries. You should also keep a copy of any good working Post Processor in a Folder somewhere away from Fusion on your computer !!

Meanwhile you can try the attached Grbl 6axis Post Processor, it is currently set for A and B axis but can be easily changed if needed, it is an older one from Dec 2020 so hope it helps 🙂

Usual Caveat applies, use carefully and at your own risk 🙂 🙂

[sa_sa_go]

Thanks! Managed to find the problem, I had A axis aligned with Y axis, when changing my WCS the problem got solved, now I have another problem. Is there a way to deactivate C axis from postprocessor? My GRBL reader is 5 axis only and it does not recognize C command

[engineguy]

@sa_sa_go 

Below is an image of the Grbl PP showing the way it is set up for 5 axis in a XYZ-AB configuration, if the C axis is showing the same as the A and B then just put the two // at the beginning and it should go Green and then change the line that says what the axis configuration is to (aAxis, bAxis) as in the image.

[sa_sa_go]

Awesome! Thank you!