Thanks in advance for any tips or answers. Photos attached for references.
Problem I am running into is hot spots within my vector lines that result from laser power remaining steady while the laser speed slows down to turn corners. I have not run into the problem before but I have recently torn down and rebuilt my machine (with addition of a stepper motor for automated z axis). As far as I recall, I don’t believe any machine settings were altered other than the inclusion of Z Axis.
Most common cause of this issue seems to be PWM settings but these appear to be correct. Laser mode is enabled. Cut settings for a line (not fill) appear to be logical and basic with no odd settings (like constant power mode).
I thought perhaps the 3 pin/wire laser cable could have bad continuity, but multimeter tested good from each endpoint.
I thought maybe the laser driver on the module could be bad but swapping it out with another gave the same results.
Physically/hardware I think everything is set up properly. I have photo of cable at the board and at the laser.
Software wise looks to be set up correct.
I’ve included my $ settings at bottom.
My layer settings are generally between 1200-2200 speed and up to 50% max power. Min power is usually set to 1 or 0 when doing raster.
Min PWM is set to 1, $35. (I have also tried 0 with no success)
Current lasers I’ve used during issue are 2.5w diode.
My board is an eleksmaker 3 axis with Tim Rothman’s black and blue nano. Eleks-extra expansion for the limit switches. Nema17 steppers (4 total YY, X, Z)
Check that your device type is in fact “GRBL”. Push “Devices” button in Laser window. Then click on the name of your laser. On the bottom of that window it will show you the device type. If it’s set to GRBL-M3 or other device type then Edit the device and change to GRBL.
If that’s not it can you provide the following:
Can you confirm if power can be modulated using the Fire button in Move window?
Confirm that S Value Max is set to 1000 in Edit->Device Settings
With a simple design loaded do File->Save gcode and save the file with a .txt extension and upload here
@jkwilborn It’s a Frankenstein to a degree… Original purchase was an Eleksmaker Mega which is the 2x2 foot area engraver.
From there I did the recommended upgrades to nema17 steppers, 16 tooth pulleys, the 32bit ‘black and blue’ nano by Tim Rothman. I believe the original nano is/was 8 bit for eleksmaker boards.
Upped to the eleksmaker 3axis board from the original 2 axis mana board. New stepper motor drivers (tmc2208s), original were the A4988, I think. Added the Eleks-extra expansion panel which just gives you some plug and play limit switch connections. (and a few other connects that I’ve never used)
From there I installed 2 switches to control 2 different 12v fans. One is attached to the back of the laser mount to trail around the surface and blow any residual smoke and debris out of the way. The other is mounted into the board case to cool down stepper drivers.
The last upgrade was the auto-Z axis which I just picked up off ebay for about 70 bucks. The unit is more heavy duty than I expected… I believe it’s tolerance is to actually hold a CNC router head/dremel or something. To save some weight and space I removed the two front mounting plates and 3d printed a specific mount that is easy enough to swap out for different sized lasers. (my 2.5w, 3.5w, 5.5w 15w, 10w, all have slightly different size of heatsinks.
So I did what I could to retrofit it onto the x axis and balance the weight around as best I could. It seems to function well enough so far.
I also swapped out the assembly of the bottom wheels for each axis to try to maintain better tension. The original set up was simply two sets of 2 spacers a wheel and a nut. The new set up is a 3d printed frame that holds the wheels in their respective place with an independent tension m4 nut in the middle. This is then locked in place when mounted to the axis acrylic plates.
Kind of just running through this all off top of head but if you want better explanations or pics of anything just let me know and I’ll try to get that when I have a moment.
Here’s what I found so far. You may be onto something with the Device being incorrect. It seems it is set to Grbl M-3. (have not changed it yet to troubleshoot as suggested. I will in a bit)
Oops… Yes you are correct… Here is the line from the grbl setup in the Lightburn documentation…
You might need to adjust your spindle max RPM value ($30) to match the LightBurn default (1000) or vice versa. The value in LightBurn is called “S-Value Max”, in the Device Settings.
You might need to enable “Laser Mode” if you have GRBL 1.1f or later ($32=1)
