Laser engraving - not really getting great results

Confirmed for the 5V, using the 12V fan port the signal is not as sharp (?) the peaks are rounded over slightly.

David the bad picture you got from the mini was a 5V signal laser or 12V?

Hmmm, adaptive step smoothing, or S Curve Acceleration would be my first guesses.

Heath is having the same issue with a RAMPS board, but the latest firmware.

I would be suspect of that theory. Kelly’s not here to say how long he has had his mini Rambo that Ryan flashed. But I was under the impression that he has had it for a while. If that is so then I would have assumed he was on an earlier version of the firmware. I could be 100% wrong. I am making a guess. But even I can help to test that. My laser was cutting fine with Marlin 1.1.5 the other day. I was going to upgrade to 2.0 soon anyway. I’ll flash 2.0 Firmware and see how Garfield looks. I will use Ryan’s 2.0 firmware for the MiniRambo and just change the Motherboard to match my MKS. Not an ideal apples to apples test but close.

1 Like

But it’s not a true RAMPS. It’s the MKS GEN L which is a RAMPS and Mega on a single board. But it uses RAMPS firmware. I wonder if the “single board” controllers have something to do with it?

Mine is an MKS Base v1.2. Older than your Gen L I think but same concept. Arduino and Ramps built into the same board. Since mine was working I’ll gladly try to break it. I can always reflash back to my trusty 1.1.5 version if I need.

1 Like

It may be worth going back to the real RAMPS for testing. I just have to power the Mega from USB, but that’s doable long enough to test.

I am plugging in my laser right now, I suspect S curve accel doing it, it makes the most sense to me. Compounding accels trowing off the trigger point.

Well crud. I popped my laser It just will not focus anymore.

So Junction deviation, or S curve. If you guys can try turning that off in the firmware, I am willing to bet it is one of those.

M3…no good for lasers it has to be M106. So on the mini just change fan pin to 10 and use Z min as your port.



[attachment file=88214]

I’m running Garfield right now – the miniRAMBO board hooked up exactly as before (I never dismantled it…) – and the image is sharp and crisp, just like the RAMPS runs I did before. What changed?

I reflashed the miniRAMBO board with the same MPCNC813-GLCD firmware as on the RAMPS boards… changing only the board name, remapping the FAN pin to pin 10 (Z-MIN), and cutting all the steps/mm settings to accommodate the 1/16 microstepping.

That’s all I changed.

I’m stoked! I need to go pour a glass of wine and wait for this engraving to finish. I post the results in a bit…

– David



I ran a series of tests with just about every combination of discussed firmware settings. The only ones of note were 7, 8, and 9.

7 was with Junction Deviation disabled.

8 was with S Curve disanled.

9 was with both disabled.

All 3 with Spindle-Laser disabled and using M106 commands with the fan pin remapped to pin 44.

I guess this is improvement? This was a different material so I need to test with the same material I was using before.

This was all with the Marlin 2.0 firmware.[attachment file=“IMG_08022019_191906_(1080_x_525_pixel).jpg”]
[attachment file=“IMG_08022019_191917_(1080_x_525_pixel).jpg”]


I am trying to wire up my other laser now, strap it on with a few zip ties. It has to be one of those two settings. I will be following along in a few minutes again.

David, can you post a zip of the two versions? Working and non working?

miniRAMBO reflashed with the MPCNC813_GLCD firmware downloaded from this site… probably a year ago.

[attachment file=88226]

[attachment file=88227]

I changed only the board name, remapped the FAN pin to pin 10 (Z-MIN), and cut the steps/mm in half to accommodate the 1/16 microstepping.

– David



1 Like

Where can I download the MPCNC813_GLCD firmware?

Here’s the good one…

[attachment file=88231]

The other is too big to attach… but it was downloaded from Github… (759 KB)


Well, I have every “new” marlin 2.0 setting off, matched accels/jerk between firmwares. Mine is not perfect but not as bad as some that I have seen.

What settings are you using for imagetogcode? Or are you using the same file from early in this thread?


What really gets me is all the accelerations that are happening, fan speed changes should not induce an acceleration change in motion.

I’ve not changed the Garfield gcode file at all… it has been the same exact file for all the testing I’ve done. And it’s the same one I shared earlier…

Okay using that file in this version of 2.0 I am getting a good burn (I think, hard to see in these glasses). I will turn each setting back on one at a time and see where it breaks.