Bought a brand new Gweike G2 20W 150mm x 150mm laser, my first laser. Setup information is pretty sparse for this thing, so I assume I’m just missing something “obvious.”
Using a Windows 10 PC with a freshly started demo download of Lightburn.
Steps taken:
Installed device drivers from included USB thumbdrive
Followed the PDF setup guide here, which is pretty close (though not identical numbers) to the parameters screenshots included on the thumbdrive.
Tried following the advice in a similar thread on these forums here but have zero evidence of the fiber laser firing.
Double and triple checked wiring to make sure everything was fully seated and properly oriented.
Lightburn doesn’t auto-detect the laser when installing a new device, but that seems to be normal for these from what I can find. Added it manually. Framing works fine with the red laser. When I hit start, the path is traced out by the red laser for however many passes I specify, I just don’t seem to have any output from the fiber laser.
It seems my power was just set too low. Is it typical for these machines to not fire if the power is turned down? I was trying to run 35% power and had no perceivable output. I tried running at 100% and it came to life. Seems a silly issue to have, but this is how you learn!
I assume you tried to focus it? … if the focus is off, it won’t appear to lase. Seems indicative that it will lase at higher power, the focus being off enough for this to appear the problem.
It’s a solid state pumped fiber laser, so it should work at very low power levels, theoretically at 1% if need be. I know I’ve run mine below 5% power with no issues.
You didn’t include how fast you are moving, power setting or what your q-pulse and frequency settings are. There might be more of a clue here.
Added: I have large pieces of metal, and I move them around +/- the area you think it should be focused by hand. You can do it fast and make a quick determination of focus although a bit rough by sound.
I did try to focus, that was the first suggested fix I found searching around. I ran a filled square for 10 passes and both moved the head up and down, and lifted/lowered a piece of plastic and didn’t notice any changes. After it came to life I did a quick engrave on one of the coated aluminum business cards and decided to pause any further adventures while I 3d print some bits to put together an exhaust vent, which I haven’t found the time to finish yet. Anyway, I do wonder if attempting to see results on 3d printed PLA instead of something like one of the aluminum business cards maybe sort of hid things from me.
For these tests I was running 1000 mm/s, 35% power, and I believe 30 kHz. Have to admit I don’t even know what q-pulse is, and I don’t immediately see a box for it, so that would’ve been whatever Lightburn thought was best
The one successful engrave I did on the aluminum card was done with the same settings, but turned up to 100%. Once I have time to get some ventilation set up, my first thought is to dial in focus with one of the business cards. From there I figure I’ll adjust delays and start running power/freq sample arrays on things to start building some intuition for how each setting impacts things.
At this point, I don’t know if I can really help you. I have nothing that I can measure the output with or know exactly how to tell if the controller is sending the correct information to the laser source.
You will probably have to go back to your vendor and let them know you’re having issues.
Fiber lasers are generally used as pulse lasers. The advantage of a Master Oscillator Power Amplifier (MOPA) is it allows the operator to modify the pulse output waveform of the laser better than other fiber lasers. Frequency changes pulses/mm and q-pulse relates to how long the fiber is open to drain.
Gweike G2 is a solid little unit, but yeah, the setup docs suck. Don’t sweat it, you’re not doing anything wrong—this is just the usual grind when jumping into fiber.
So if the red laser’s tracing the path but the fiber’s not burning anything, it’s probably one of two things: either your focus is way off, or your power/frequency combo just isn’t enough to touch the material—especially if you’re testing on PLA or light plastic. Fiber lasers just don’t do squat on that stuff unless it’s dialed in just right.
You said it marked on the aluminum card when you cranked it to 100%—that’s your proof the laser’s working. So here’s what I’d do: forget PLA for now. Use one of those anodized business cards, set the speed to 1000 mm/s, power to 100%, frequency around 30 kHz, and do a quick 10mm filled square.
Now run a focus ramp—move the Z-axis in small steps as it runs and watch where the line gets darkest and sharpest. That’s your focus point. You gotta lock that in before anything else.
Also, don’t worry about q-pulse yet. You won’t need that unless you’re deep into color marking or doing stainless etching. For now, you just want consistent, visible burns so you can build a baseline.
Once you’ve got focus nailed, everything else (delays, power/freq combos, etc.) will start making a hell of a lot more sense.
