Prints have stopped adhering to print bed

[richvoid794]

Hi Everyone,

So since i got my printer ive been printing successfully, ive gone through around a half a litre of resin printing.

Yesterday i found all my prints stuck to the fep, i thought it must be to do with how i positioned the the stls.

Ive tried the following:

Releveling the print head, hasnt seemed to work.
Cleaned everything with IPA
Tried a test run, with no head or vat, everything seems to move and be lit up as i would expect.

im using elegoo black resin, i dont think my settings are wrong used half a bottle already.

Does the FEP only last a certain amount of prints?

Thanks
Rich

[zemerick]

Yes, FEP only lasts so long. Over time, it gets cloudier and has more and more scratches, dents, etc. How long it lasts varies immensely, just like the LCD itself.

If the FEP doesn't look pretty bad, and has no rips/holes, that probably isn't it though.

Almost always, adhesion comes down to bottom layer exposure. This goes 10x for black, which is probably the second worst color to use in general. ( It has its use, but its limited and requires a lot of effort. )

For straight black, I never recommend using .05mm layer height, that's just asking for trouble. I also would use nothing under 150s bottom layer exposure. Normal exposure is the difficult one to get dialed in: Anything a little too high and you are ruining the detail that is the only real point of using black. Just a touch too low though, and it won't cure through the layer causing problems.

Note: You could easily have settings that work for awhile, then a small change you didn't consider causes it to start to fail because you were already pushing against the edge without realizing it. Things like the FEP, but also temperature and humidity for example.

Really though, your life will be a lot better if you drop straight black. It's not a total loss though: What I personally do is mix white in to bring it down. At 50/50 black and white, you get a nice dark grey that is far easier to work with. .04mm layer height, 10.5s normal exposure, 120s bottom exposure does great for me. You could also mix grey at something like 2 parts grey, 1 part black or something similar.

[sujitvasanth]

I had the same problem after changin to a differnt colour (esun yellow biobased PLA from transparent green/grass green esun biobased PLA). I tried everthing - zaxis calibration, lubricating the fep film. Eventually solved the problem - differentg colour needed vastly longer exposure (I doubled it) ...now sticks to the build plate every time....
So whern you have dialled in your settings ( i had printed very well with 3l) dont assume the sae brand will have same exposure times...

[zemerick]

I had the same problem after changin to a differnt colour (esun yellow biobased PLA from transparent green/grass green esun biobased PLA). I tried everthing - zaxis calibration, lubricating the fep film. Eventually solved the problem - differentg colour needed vastly longer exposure (I doubled it) ...now sticks to the build plate every time....
So whern you have dialled in your settings ( i had printed very well with 3l) dont assume the sae brand will have same exposure times...

Yup: We print using light, and color is how a material interacts with light. So the color is absolutely critical. This is an extremely common "noob trap", that most of us have fallen for. Color should be chosen based on performance desired, not its appearance...and resin manufacturers should really label this more clearly.