I’ve done some lurking on this forum and others related to this issue but can’t figure out the cause of this. Over the course of using my Comgrow Z1 Pro 20W (ordered from amazon) for 6-7 months I started to notice a double or even triple engraving where I only expected one. I started with the belts and screws as others on here recommended before narrowing it down to the laser head itself. I tested with the air assist nozzle off since some had suggested it could be blocking the beam partially or causing reflections, but this did not change things. I ended up inspecting the pattern with and without the lens to see if something looked off and I’ve attached those images down below. This is me aiming it at a nearby wall from a distance. I’ve also included the way a small engraving of a square is coming out as well and some pictures of the lens. To me it looks like the beams are not combining into a single beam as expected. What could cause this to happen? The lens looks fine to me from examining it by eye.
If the image projected in the wall is from the laser head without the lens I would say something moved inside laser module and misaligned the laser beam. If it has the lens attached, remove them and do the same test to see if the patterns maintains.
I was leaning towards this but I didn’t want it to be true. Is there any way to adjust the mirrors? I’m not seeing any obvious way to access the mirrors. I’m finding some resources about it for a CO2 laser but much less for a diode.
To better specify the images: the image with three dots is without the lens, and the one with 3-4 rectangle shapes is with the lens. Any extra noise in those images should be from reflections.
The beam without lens should be a unique spot, blured on the sides because is not focused.
The image with the lens mounted is blured because the various beams hit various points of the lens projecting various defocused beams.
You will probably have to take the chance at your own risk, disassemble the laser module and check if anything is out of place. However, it must be something so imperceptible that it will not be easy to put it back in place.
But… good luck!
In the first multidiode lasers, the mirrors were glued in a “stair -shaped” holder. In my opinion, there is no possibility of fixing “loose mirrors” in this type of laser.
You can try to ask for warranty/compensation, if the dealer/manufacturer is reasonably serious, they will avoid having customers with bad lasers from their factory.
If this applies to your case, it would be my first option.
Only if it is not under warranty or it is not necessary to return it would I opt for the more invasive intervention that I mentioned.
@bernd.dk I never disassemble one so I don’t know how laser modules are assembled. If I had a defective laser module that it safe to disassemble I would do it.
But it’s like you said. If it is possible to return or get a refund, that is the best option.
I do not think even the new ones are perfectly collimated (I think that is the right word). I had a conversation about this with @misken. He is the Guru for my machines, and it appears this is pretty much normal. It does explain why the dot size gets bigger with more diodes.
If you look at the lower right image, you can see 4 lines, due to 4 diodes in a 20w laser head. That pattern looks very much like the pattern from my brand new SF-A9 in the 20w mode. Maybe you noticed it now because you are doing a better job with the focus?
In my opinion, you are trying to fix what ain’t broke. You did not show us a picture of the " double or even triple engraving". What were you engraving?
I’d say either the mirrors are loose, as you already diagnosed, or even two of the diodes have died. A proper spot of a 20W (4 diodes) head should look similar to this:
Thank you to you and @bernd.dk both for your input on this. It unfortunately confirms what I was worried about. I’ve been trying to reach out to comgrow first via email, but it took me multiple tries to even find an email that went through, so I’m not super optimistic about the support I’m going to receive on that front. I’ll keep this thread updated if I hear anything or if I end up having to open the laser module up.
I’m definitely learning more about focusing and the inner workings of a diode laser through this! But I do think something is broken in this case unfortunately. I’ve attached two images showing some of the double (or even triple) results that I started getting after some time. The one with the squares shows a few months ago near the top compared to more recently where the vertical edge of the square is split into 3 lines.
Thank you for this, I wasn’t sure exactly how the spot should have looked and it’s good to see what it should look like. My image without the lens only shows 3 spots, while the image with the lens shows 4 rectangle spots, just not in a perfect line for some reason. Hopefully not dead diodes as you suggested but it could be.
On another note, I happened to spot this tonight after I fogged up the lens trying to blow off some dust. It looks very similar to the spot pattern I’m seeing too. Any idea where I could pick up a new lens like this one or how I could go about searching for one? I’d be thrilled if my problem was this simple.
Oh nice, I wouldn’t have thought to look on etsy. My fault for the bad angles on that piece but I think it is the lens not the protective part. In the images I’ve attached below the piece on the left is the one with the marking I just spotted, and the one on the right which is bigger is the outermost lens, which appears to be fine by eye.
I’ve tried to do some searching for things like “diode laser lens” but am not having much luck so far.
Now that the images were posted, I had a good pause regarding the laser module having problems.
What I see in the images could very well be a mechanical problem. In one of the images you can see a point (which may have been used for focusing, I don’t know) that point seems reasonable to me for a good laser beam.
The image with the supposed lens may also just be glass and not the lens itself. My laser has a protective glass that I’ve had to change more than once. But in my case the beam was blurred but uniformly not as divided as in your case.
If it is a protective glass it as to be perfectly flat. If it is a lens as to be concave.
Discoloring could be result of fumes, that you can try to clean with alcool and a swab. If it is “old” fumes it already burn the glass/lens it self and you can’t clean it.
So evaluate the situation very well before make unnecessary expenses.
