I’m trying to use lightburn for my plasma cutter but I’m having a hard time making it pierce/cut through and KEEPING the arc on.
I tried manually editing the gcode and found out that lightburn adds
G1 S0 , G0 and M5
just to run M3 right after
So in my case the dwell I add in “start pause time” doesnt matter because the arc is turned off right after again . Maybe thats ok if its a laser but a plasma cannot be started that quickly.
Unfortunately for plasma process, I seem to recall the gcode gen that you are experiencing as being normal for LB under the circumstance of ‘cut-through’ with dwell, and for device profile of GRBL-M3. I don’t recall the rationale but I suspect certain laser machines required that behavior.
I’ve been using LB for my plasma table for over 2 years now and I recall that toolpath code gen as being one of the conditions that drove me to post process the LB gcode at first in the early days of my plasma table use, but other conditions inhibiting a smooth and error free work flow and final toolpath gen drove me to simply build the plasma toolpath with SheetCAM after importing the LB .svg file. The LB/SC workflow has proven to be an excellent combination in all respects.
All that said, LB is addressing this and other issues with ‘other than laser’ toolpaths with a ‘Generic GCode’ device profile that is currently in beta v1.5. You basically write your own custom gcode blocks for CNC process and operation events, such as ‘Pierce’ or ‘OnPenDown’. Send LB Support an email to inquire.
Send me a PM for more information if you choose the LB/SC approach, I’d be happy to assist you.
Hi @bLouChip thanks for the quick respons. Glad to hear that I am not alone . I’ve heard alot positive about sheetcam but for now I would very much prefer not paying for their license just for my little hobby (and yes I know you can use it free up to 180lines of gcode)
Anywhere I can read about the ‘other than laser’ toolpaths? have you tried it?
re. LB beta 1.5 with “Generic GCode” device profile. Yes I’ve tried it briefly from a very early build back in Oct. I liked what I saw but it had a bug (has since been fixed I’m told) that prevented me from trying the gcode on my plasma table. I plan to jump into it again in a few weeks, letting it mature for now.
Lately I’ve been fairly heads down on adding general purpose usage and rotary support to my custom grbl SheetCAM post processor as it gets shared/picked up with a broader set of users.
The LB 1.5 beta was announced during the LBX conference 10/28/23. Its all very new info and most of what is in process of being written is in development and limited to the beta community I believe. Publicly there are videos of the conference speakers and announcements, with some demo. I’m cross linking to this post with those videos and timelines within. Router-based software similar to Lightburn? - #11 by JohnJohn
Beyond that info, If you want to join the beta, send LB (LightBurn Software support@lightburnsoftware.com) an email to inquire.
I should have added that in the absence of either entering the LB beta 1.5 or using SheetCAM, you are welcome to check out the Vim editor script I was using to post process LB’s laser gcode, transforming it to plasma capable with THC, over a year ago. That was very successful and served its purpose during my plasma table startup. The issues that drove me to SheetCAM had to do with LB UI as it concerned needing to first verify and then manually adjust as needed the leadin placement (and start point), cut direction, and from a workflow basis having to redo many of those with seemingly simple changes to the LB drawing. See this post for the script. Update on plasma use case success, albeit post processing gcode
Yes. My machine has swappable milling, plasma, and laser cutting heads. In the case of laser rotary, I’ve been using LB for gcode and control/sender for about a year now. In the case of simple pocket and vbit milling (2.5D I suppose), I use SC for toolpath; and as mentioned for plasma also, and UGS for control/sender.
I’m adding rotary toolpath support for milling and plasma; round pipe/tubing is done and ready to test, now working on including code for rectangular tubing. SC already handles 95% of the toolpath math for correct motion, the task in the user exit points of the post processor is to invoke the right APIs and reference the right SC global variables to produce grbl dialect specific to a machine controller, and still allow for runtime options specific to a CNC machine implementation with such things as THC, per-cut torch zeroing, tool changer, air supply recovery, etc. It’s interesting and fun
