Laser focus issue?

Hi, I’ve had the moai for a couple of years and have had some great prints from it. Recently I had to replace the galvo as the original mirrors had become marked. What I’ve found since installing the new galvo is that there seems to be a focus issue with the laser.
I’ve trawled the forum for similar scenarios and have found the photo of the test ring on this thread best represents what I’m getting -
Like in the image of the test ring, I am using peopoly blue resin and there is a small “skirt” on the initial layer and sometimes I get ragging/fins on my print. I have tried changing laser power etc. monitor the temperature (it’s about 25c with the heater installed) checked the laser path for obstruction (even using a new dust shield) and I have been using a new pdms vat.
Any advice would be greatly appreciated.

the diode was reported back and fix quite a while ago. The “skirts” you see now are usually from overcured layer by the new profile. the “fins” however, usually comes from the slicer or leveling, checking those 2 should give us some informations.

Hi, Thanks for getting back to me. I’ve checked the levelling multiple times and have found that to be ok. I’ve tried using both the easy level and the original build plates.
I’m not sure if the new galvo is causing issues as the reason I replaced the original one was because I couldn’t even get a print in any form. Now I am getting it to print consistently it’s just that the quality is not great and I’m getting the over curing you mention and visible layer lines.
With regard slicer I use asura exclusively for the moai.
What do I need to be looking at to solve these issues?
I really appreciate any advice.

visible layer lines can be either caused by peel force or the heater, without any pictures i can’t tell you which
try switching to Cura or any other SLA slicer, users usually do that and it doesn’t have anything to do with the galvo. A bad galvo is something we almost never have to mention

Most often loss of detail is dirt on the Galvo. There is the possibility that your FEP or PDMS vat has started to turn opaque too from heavy use. I have seen FEP films tear and leak resin slowly onto the acrylic, which is much more obvious on the PDMS.

After a proper cleaning you should see layer lines on certain surfaces printed <45 degrees at 50um. Though, what is pictured seems to be a loss of focus from dirt or fogging. I have experienced a laser go bad (loss of focus) and prints would still print, I just lost any detail <1mm at first. Then prints would turn wavy, especially flat mechanical prints. Finally, the print would lose detail and would print like a bunchy of plates stacked on top of each other.

I designed this file and would suggest you use it to test. It’s hollowed and ready to go, and results on my machine after a laser replacement keep detail and is a good point of comparison.

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That’s great. Thank you for the advice and the model, I will run some test pieces to see what happens. As mentioned I have cleaned everything in the laser path to the plate or it is new (I have been using a new PDMS Vat). I have now started using Cura to slice the components which has helped but not totally eliminated the problems. I’ve found that I have needed to turn the laser power down (53 for peopoly blue resin) along with the print speed.
How would I know if it’s an issue with the laser? are there any tell tale signs that I should be looking for?

Thanks again for all the advice

If you can’t see the words included on the sides of the print, if you can’t print the 1mm lattuce, if it looks like there were flakes cured resin that somehow wound up in your resin. The attached picture is of my failing laser. After replacing it worked great. The clue before this was the tiny detail on the flat side, lettering, that did not show up. I thought it was the new resin but after switching back to Peopoly resin it was obvious that it wasn’t.