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Printing channels. It work but now it is clogged using new resin

We are printing a tube with integrated channels, we’ve been using the Clear Resin V4 and it’s worked successfully in the past, but we just started using a new tank of resin (Lot 20210916) and now the channels are clogging solid. We tried changing the print orientation (didn’t help). Any thoughts on why this is happening or suggestions to fix the clogs? Could it be from mixing an old and new tank together?

Need to clean the bottom of the tray or the lens?? Thanks

Trays wear out. Mirrors get dirty. In both cases, the beam becomes “fuzzier” and the resulting prints lose fine detail, they get “blurry”.

If you’ve had this Form2 for a while and you’ve never cleaned the mirrors, you are probably due for this. There are instructions in the support part of this forum, read them and follow them exactly or you risk damaging the printer’s mirrors.

If the Form2 is fairly new, then probably your resin tray is wearing out. If you go to the Dashboard and select the tray from the list, you should be able to display a “heat map” that shows where the resin tray is most heavily worn (darkest color). If there are a lot of really dark areas, then you need a new tray.

Regardless of the printers age, I think Randy is right in that the mirrors are suspect. The 2’s often came from the factory with dirty mirrors, and one fine day the dust is too much. I’ve also noticed that some resins outgas, and the mirrors fog up over time.

Also, take a look through the resin tray after draining out the resin. It’s an alternative to looking at the heat map. If it’s at all cloudy, replace it. (You can get a quick read just by scraping the resin off to one side and shining a flashlight onto the tray bottom).

If the mirrors look clean, I’d just replace the tray regardless; they’re not that expensive, and it’s a more likely culprit than a bad batch of resin.

On reflection, I’d replace the tank as a first go; dust on the mirrors would more likely cause a print failure, rather than goop. And the mirrors are a pain in the ass to clean. Worse case you can always put the old tray back into service if that wasn’t the cause.

One other thought; make sure there aren’t any floating particles of hardened resin in the tray; they can cause the resin to develop a higher viscosity, and flare, hardening areas that shouldn’t, while still letting you finish the print.

Good luck!

The “laser deck” of the Form2 is closed, in stark contrast to the Form1’s totally exposed mirrors. But it’s not hermetically sealed so environmental organics get in, and, I suspect, the materials inside like lubricants and PCBAs may outgas as well. The resins could well contribute - if you can smell them they’re outgassing - but the mirrors will haze with time no matter what.

Thank you, Randy and Rob for the helpful advice. We now have better directions to troubleshoot. Happy New Year!


Hi, I have the same issue and after cleaning the optical window and changing a new tray, the test printing is shown as attachment. Could anyone suggest what should I do next to fix the issue?
Thank you very much for any help.

You need to clean the mirrors inside the printer next. Though, the Form2 tests laser power at the start of each print and that data is reported back to Formlabs. So you could ask them to check your printer to let you know if the laser is having problems before you go to the effort to taking the machine apart to clean the insides. If the laser is failing, no amount of cleaning will help.

I cleaned the lens, glass, and mirror today and it did not help one bit. I really don’t understand why the print quality all of a sudden can drop so much after perfect runs. This current printer is a replacement (reconditioned) unit sent by Formlab after my relative new Formlab2 had the exact same problem prior to the expiration of the one-year warranty.

I also used new resin and the tray is almost new so I don’t think they are the cause of my problem. Maybe the laser power can drop drastically and maybe I can call Formlab to let them check it.