Crust in Resin Tank

can anyone tell me why in the Resin Tank forms a crust? Does it depend on the temperature?
What can I do to prevent?
The tank is 15 hours old, clean and transparent. the White Resin new
Thanks for your help

It doesn’t form a crust. I’ve been using FormLabs printers for almost 2 years now and I have never seen this happen. There’s something wrong. Either the resin is bad, or UV light from somewhere is exposing the resin.

I’m inclined to say it’s UV and not bad resin. Given the “crust” is dead center in the middle of the tank, I have to wonder if the Laser is shutting off completely. Powered down, the galvos probably end up pointed at the center of the resin tray.

I suggest an experiment… scoop that crust out of the tank, let the printer sit overnight and see if it reforms a crust. If it does, scoop out the new crust and unplug the printer and let it sit over night (both cases, with the cover closed). Still get a crust, it’s something to do with the resin itself. If you don’t get a crust, there’s a problem with your printer and you need to open a ticket with FL to get it fixed.

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Hi, Randy
many thanks for your answer. The printer is in the cellar in the dark what excludes any source of light.
Anyway, last night the printer was off and no scab has formed. I printed a copy this morning. Without problems !!!
I keep a diary. So I’ve found that between 40 to 60 hours the crust forms.
Yesterday I printed in 82 min. a small piece. Right after I wanted to print a copy. And it was there that the crust is formed. I noticed when start printing, the resin was already hot, above 30 ° exactly 34.2 ° it’s normal? After how many hour you change the Resin Tank?

I am not sure I understand. You printed one object in 82 minutes and when you went to print another copy the crust had formed? But if it takes 40-60 hours to form, I don’t see how the crust formed between the first and second print.

If the crust doesn’t form if the printer is turned off, and it does form after 40+ hours of time if the printer is powered, then I would say the problem is that the laser driver circuit isn’t shutting off completely, the laser is always on, just not very brightly so you don’t notice. But over a long period of time even at low intensity the laser light is enough to cure the resin and create the scab you’re getting.

Yes, the resin is supposed to heat up. Printing starts at 30ºC but the resin continues to heat to 34 or 35ºC.

I’m about to replace my first resin tank on my Form2. I’ve printed about 2L of Tough 01 resin with this tray. I would say about 24 prints in total ranging in size from single large objects to many smaller objects. The tray still seems to be printing fine, but I’m switching to a Tough 02 resin and will begin again with a new tray when I make that switch.

hi Randy,
I apologize for my precarious English.
the Tank was 17 hours old when I printed the first piece. (82min)
Immediately after that I started to print a copy. After 82 min. I found a crust but not a copy.
I turned off the printer overnight. In the morning I turned on again the printer and have successfully printed the copy. I have not changed anything I just cleaned the tank from the crust the night before.
Thank you for your patience. Gianni

Ahhh. That is much clearer!

When you checked in the morning and found the crust, was there anything stuck to the build plate or was all the cured resin floating in the resin tank? How big was the chunk of crust? Was it the full depth of the resin tank or only floating on the surface of the resin?

You should see if you can replicate the behavior by attempting to print your object twice in a row again. If the printer has a thermal “sensitivity”, that might explain your problem. It works fine until it gets hot enough, so a single print doesn’t screw it up, but two in a row does. Looks to me about how I’d expect if the build plate was never engaged during the print, like it just stayed in the elevated “parked” position and the laser just cured whatever resin it managed to hit.

You probably want to open a ticket with FL support.

Thank you. i open a ticket with FL support. By by Gianni

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