Octoprint for Laser & CNC - UPDATE

Bill Arnold

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During my trials and tribulations with bCNC and CNCjs, I came across an Octoprint Add-In called 'Better Grbl Support'. I've done some testing with it on my laser engraver and it seems to do the job just fine. I'm setting up an SD card to swap into my CNC for further testing. More on this as it develops, but so far I'm liking it!

Octoprint-Laser 2019-09-09 17.28.53.jpg

Does anyone else have any information about this add-in?
 
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Brent Dowell

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During my trials and tribulations with bCNC and CNCjs, I came across an Octoprint Add-In called 'Better Grbl Support'. I've done some testing with it on my laser engraver and it seems to do the job just fine. I'm setting up an SD card to swap into my CNC for further testing. More on this as it develops, but so far I'm liking it!

View attachment 107822

Does anyone else have any information about this add-in?


Nice, Not bad at all. I do like octoprint a lot.
 

Bill Arnold

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As I continued to play with this plug-in, I ran into an issue. I posted it to the Octoprint and github forums. Here's the content of my posts:

"I've used Octoprint on my 3D printer for a couple of years and was interested to see a laser plugin for it. I added the Laser plugin to Octoprint on my laser engraver and like what I see - with an exception. I was seeing artifacts in a photo I was test-printing, then saw more definite lines when printing a gradient image. I went through steps of eliminating different parts of the communication path to determine the item causing the issue.

My system consists of an RPi3 feeding an Arduino/BOB unit to drive the steppers and a laser driver module to operate the laser itself. I bypassed the RPi to start with and got smooth prints. Then, I set up two SD cards - one with Octoprint Laser and one with bCNC to further drill into the cause. It turns out that the print discrepancy only occurs when using Octoprint Laser to feed the gcode to the system. Attached is a photo showing the result using Octoprint Laser on the left and bCNC on the right.
Suggestions?"

Grad20190827a.jpg

So, the ball is in the plug-in writer's hands now. More as it develops.
 

Brent Dowell

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That is interesting. Is the machine moving smoothly the whole time, or does it primarily have to do with how the laser is being controlled?

You'd think the same gcode would print the same, no matter what was sending it.
 

Bill Arnold

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That is interesting. Is the machine moving smoothly the whole time, or does it primarily have to do with how the laser is being controlled?

You'd think the same gcode would print the same, no matter what was sending it.

The machine moves smoothly when I do it manually. I ran the same gcode file with Octoprint/Laser and bCNC with results as shown. When I run the image directly from LightBurn, it's smooth. It appears to be a problem with the way Octoprint/Laser sends the code. I've never noticed a vibration on my 3D printer, so it sure looks like the plug-in is affecting the machine in some way.
 

Brent Dowell

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Not that this is directly related, but I know when I was playing around with using smoothie versus grbl firmware on my controller, that grbl had better handling of the communications. The laser gcode really loads up a lot of spindle/laser control messages and smoothie had a hard time keeping up, so I'd really have to slow the travel speed down to keep up.

I'm wondering if the octopring plugin just doesn't handle the comms as well, but then I'd think you would see some sort of stuttering on the x/y movement.

I'm still pretty happy with CNCjs though.
 

Bill Arnold

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... I'm still pretty happy with CNCjs though.

I'm thinking about going back to CNCjs. I did some testing with it a few months ago, but had trouble getting it set up to run on RPi. I know it should run on RPi, so I'll have to take a new, more patient look at it. In the meantime, I can use LightBurn to feed my laser directly.
 

Brent Dowell

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I'm thinking about going back to CNCjs. I did some testing with it a few months ago, but had trouble getting it set up to run on RPi. I know it should run on RPi, so I'll have to take a new, more patient look at it. In the meantime, I can use LightBurn to feed my laser directly.

I do love lightburn that is for sure.
 

Nelli Balzer

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Ashburn, Virginia, USA
Hi...I've seen endeavors at terraforming the OctoPrint interface with a total redesign which wound up so appalling that no one could chip away at it. Getting a few switches into OctoPrint itself would be favored for this situation, I'd recommend. In any case, on the other hand, I'm not the one doing PRs so foosel would be the individual who ought to say something here.

pcb assembly online quote
 
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