GRBL Post processor for Sheetcam

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CBoy
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GRBL Post processor for Sheetcam

Post by CBoy » Thu Nov 23, 2017 11:08 am

Hey blokes,

I have been building a CNC plasma table for the last few months now, I had it running as a Router table first just to learn more about CNC machines first before I dived straight into Plasma. (I have had no CNC experience what so ever and I'm just an electrician so had to take baby steps to learn).


My machine is running an GRBL based Arduino platform based controller called a CNC Xpro V3 controller board which is basically just an arduino with everything packaged up neatly to use for a CNC machine.

So I have a relay off the spindle control circuit off that board which closes the switch on my plasma trigger.

I have got a few basic things cut out with it, using Fusion 360 and its inbuilt CAM software, but it only has basic plasma features no nesting or anything like that. So I downloaded sheetcam to see what its like and seems to have all the features that I need once I learn how to use it.

My question is, does any one know if there is a post processor for sheetcam that will support my GRBL based controller, or is it easier for me to convert my controller to mach3 so that I can also implement a THC?

Just a newby after some guidance please...

Thanks
C-Boy
Attachments
CNCMACHINE_n.jpg
CNCMACHINE_n.jpg (147.03 KiB) Viewed 421 times

moose4621
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Post by moose4621 » Wed Dec 06, 2017 8:44 pm

Nice build. :D
I am at the same stage as you and thought I would add weight to your question in the hope that someone has already written a post processor for GRBL.

I have used a CNC shield on an arduino uno controlled from a headless Raspberry Pi which seems to work well.

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Les Newell
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Post by Les Newell » Thu Dec 07, 2017 5:48 pm

Here are a couple of grbl posts I have. One uses a touch-off switch and the other not.
Attachments
GRBL plasma.scpost
(2.79 KiB) Downloaded 34 times
GRBL THC with scriber.scpost
(7.84 KiB) Downloaded 27 times

moose4621
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Post by moose4621 » Sat Dec 09, 2017 9:00 pm

Les Newell wrote:Here are a couple of grbl posts I have. One uses a touch-off switch and the other not.
Awesome, thanks Les. Very much appreciated.
:D

moose4621
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Post by moose4621 » Sat Dec 09, 2017 10:07 pm

Trying to run the post without the touch and I get this error.

Code: Select all

This post has thrown an error:
...home/chris/.SheetCamTNG-dev/posts/GRBL plasma.scpost:84: attempt to perform arithmetic on global 'firstPierce' (a nil value)
Do you want to edit the post?
Line 84 reads,

Code: Select all

 if (pierceDelay + firstPierce > 0.001) then
I am not sure where the problem is.

Any help appreciated.

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Les Newell
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Post by Les Newell » Sun Dec 10, 2017 12:27 pm

It looks like somehow you are missing a chunk of the post code. That should be line 204. Try downloading and installing it again.

moose4621
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Post by moose4621 » Sun Dec 10, 2017 1:11 pm

Les Newell wrote:It looks like somehow you are missing a chunk of the post code. That should be line 204. Try downloading and installing it again.
Thanks for your response Les.

It is line 204 in the GRBL THC with scriber.scpost but it shows up as line 84 in the plain GRBL plasma.scpost

Using the same tool and operation I can post process the GRBL THC with scriber config but not the GRBL plasma config.

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Les Newell
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Post by Les Newell » Sun Dec 10, 2017 1:32 pm

Oops, I didn't realize that post had an extended first pierce. Look for:
function OnInit()
Afet that add this line:
firstPierce = firstPierceTime

That should fix it.

moose4621
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Post by moose4621 » Sun Dec 10, 2017 8:04 pm

That did the trick, thank you Les.

Much appreciated. :D

travishamilton
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Re: GRBL Post processor for Sheetcam

Post by travishamilton » Mon Jan 29, 2018 11:00 pm

I am having the same trouble with my grbl plasma setup i tryed to down load the 2 post processors from this thread but it says i can't anymore?? Can someone post a post processor that i can use with grbl please? I would make one but i have no idea what to do. Thanks

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Les Newell
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Re: GRBL Post processor for Sheetcam

Post by Les Newell » Tue Jan 30, 2018 10:41 am

It looks like attachments were lost when I upgraded the forum. Here are fresh copies of the posts. Alternatively the development verison of Sheetcam comes with them.
Attachments
GRBL THC with scriber.scpost
(7.84 KiB) Downloaded 10 times
GRBL plasma.scpost
(2.82 KiB) Downloaded 9 times

travishamilton
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Re: GRBL Post processor for Sheetcam

Post by travishamilton » Tue Jan 30, 2018 3:47 pm

Thanks Les this is going save me alot of headaches. so the scriber one I can use a touch off with my "z" is this correct?

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Les Newell
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Re: GRBL Post processor for Sheetcam

Post by Les Newell » Tue Jan 30, 2018 4:52 pm

Yes, that is correct. If you go to Options->machine->post processor and click on the 'Edit post' button you will find a number of settings at the start of the file. These need to be configured to suit your machine. You can ignore the scriber stuff.

travishamilton
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Re: GRBL Post processor for Sheetcam

Post by travishamilton » Wed Jan 31, 2018 8:13 am

Ok easy enough one more question the switch for my floating head to find material do i just connect to the z limit or to some other input on the arduino? Like i think there is a probe input also

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Les Newell
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Re: GRBL Post processor for Sheetcam

Post by Les Newell » Wed Jan 31, 2018 10:23 am

Connect the switch to the probe input.

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