Resin prints keep failing, even pre-supported. (Solved)

[The Voivod]

I've had my printer (mars 3)  for a while now, but haven't touched for some time.

In the summer I decided to get some simple prints done and then on to some models, but it's been a nightmare all of a sudden.

I first tried some pre-supported models for my kids, one of them quite big. One piece of 3 came out fine. It was somewhat on the side of the build plate, if that matters.
The rest where misprints. I checked the files and I really don't see how they would've failed this badly.

Later I just printed some bases. My computer has had a fatal crash so I needed to re-do some files I'd allready done before, but I am familiar with these kind of print jobs. I know the angle and how to support them. They came out, well flat. The prints didn't fail completely, but the bases where thinner that they where supposed to and the flat surfaces lacked detail, as if several layers where skipped.

Today I did another print, same as the first as I had promised my kids thoses models. Same results.

I've had succesfull prints earlier this year. Come to think of it, I needed to re-install chitubox, due to my pc-crash, but I never made huge changes in the settings. I'm considering I may need need to put some more space between the fep and the screen, I think I might have used to thin a piece of paper for setting the 0? Could be the fep doesn't release enough from the screen when it raises, leaving the print against the new layer?

Anyone ellse have any thoughts.

[Kelly_]

I'm considering I may need need to put some more space between the fep and the screen, I think I might have used to thin a piece of paper for setting the 0? Could be the fep doesn't release enough from the screen when it raises, leaving the print against the new layer?

Resetting the zero level would only affect the thickness of the first layer as all of the subsequent layers are relative to each other.  If it looks like you have layers combining, it could be a separation issue with the FEP not fully releasing from the printed layers… if the FEP has seen a lot of use and is stretched out, it can adhere to portions of the print during raises, not allowing resin to flow back in for the next layer or two.  Short of replacing that FEP with a newer, tighter film, you could try reslicing the stls with either a mm higher retraction height between layers or a longer time between layers to allow the FEP to fully separate from all sections of the previous layer so resin has the chance to refill the entire bottom surface of the vat.

Also, if your slicer has a preview function I would definitely watch the layer run-through before starting a print, I have had a few inexplicable errors of entirely blank layers that cleared up after deleting, then slicing a new file.

I first tried some pre-supported models for my kids, one of them quite big. One piece of 3 came out fine. It was somewhat on the side of the build plate, if that matters.
The rest where misprints. I checked the files and I really don't see how they would've failed this badly.

For the presupported stls, I would try adding additional supports and see if that clears up the issue.  The location on the plate could cause unbalancing and print failures but it is most likely lack of supports or the prior supports not having a robust enough connection point.

[The Voivod]

Thanks, I'll keep it in mind. I have it humming again just now.
I think/hope I found the problem. The screws holding the fep, especially the screws that are used to set the resin-container in position, where not all that tight. I've corrected that.
My guess is this may have caused to fep to be at an angle or not as tight as it needed to be.
Dumb mistake, but not one I had thought of.

Hadn't had the time to play around with it for a while. Hope this works.

Edit: Yep. It was something so stupid. That's probably the reason it took me so long to find someone on youtube to mention it.
Happily printing now. Struggling with supports on fine detail and hoping my new resin arrives tomorrow