All the prints get stuck to FEP

[swordman]

Hello everybody!

I got a couple of days ago an Elegoo Mars from Amazon (I don't know if that makes any difference, but mine doesn't have a batch number, in case helps
in identifying the model in any way.)

I'm seeing the same issue as xcyx: no print ever succeeded, not even the test print (two towers rooks) that came with the machine.
All the prints ends up stuck to the FEP layer (which got a couple of rinkcles after the first failed print).

I'm using two strips of masking tape on the short edges of the LCD as suggested to void suction on LCD itself.
Currently I'm thinking to change the FEP, in case the problem could be the damage from the first failed print.
Is it possible that the FEP is not tight enough? (this is how it came from the producer.) Before changing it I
wanted to be resolve the issue with adhesion though...

Things I tried:
- bed leveling as per manual, with a sheet of paper (Nothing stuck to build plate, rooks stuck on FET)
- bed leveling on the empty vat (Nothing stuck to build plate, rooks stuck on FET)
- bed leveling on vat on top of sheet of paper (Nothing stuck to build plate, rooks stuck on FET)

Now, in the last days I have done some testing  and found out this:
- Prints seems to adhere decently fine along the long sides of the build platform, but not in the middle!
I printed 9 small squares 10x10x5 and the 6 on the lines come out fine. The three in the middle row got stuck on the FEP (no support used).
- Same conditions as the test above, but with the squares 'empty' (made a square hole in each of them, leaving a 1mm thick wall), this *should* reduce
vacuum on FEP (right?) because of smaller contact surface. No support. Analogous result as the previous test, just one more piece got stuck on FEP.
- The holding nuts for the build platform must be tighten really a lot to hod firmly the build plate itself (I?m not sure if this is normal, but
seems too aggressive to be correct)

Any ideas to try more?

Best regards

NOTE: attached the test files I used

[MistaBreed]

Hello everybody!

I got a couple of days ago an Elegoo Mars from Amazon (I don't know if that makes any difference, but mine doesn't have a batch number, in case helps
in identifying the model in any way.)

I'm seeing the same issue as xcyx: no print ever succeeded, not even the test print (two towers rooks) that came with the machine.
All the prints ends up stuck to the FEP layer (which got a couple of rinkcles after the first failed print).

I'm using two strips of masking tape on the short edges of the LCD as suggested to void suction on LCD itself.
Currently I'm thinking to change the FEP, in case the problem could be the damage from the first failed print.
Is it possible that the FEP is not tight enough? (this is how it came from the producer.) Before changing it I
wanted to be resolve the issue with adhesion though...

Things I tried:
- bed leveling as per manual, with a sheet of paper (Nothing stuck to build plate, rooks stuck on FET)
- bed leveling on the empty vat (Nothing stuck to build plate, rooks stuck on FET)
- bed leveling on vat on top of sheet of paper (Nothing stuck to build plate, rooks stuck on FET)

Now, in the last days I have done some testing  and found out this:
- Prints seems to adhere decently fine along the long sides of the build platform, but not in the middle!
I printed 9 small squares 10x10x5 and the 6 on the lines come out fine. The three in the middle row got stuck on the FEP (no support used).
- Same conditions as the test above, but with the squares 'empty' (made a square hole in each of them, leaving a 1mm thick wall), this *should* reduce
vacuum on FEP (right?) because of smaller contact surface. No support. Analogous result as the previous test, just one more piece got stuck on FEP.
- The holding nuts for the build platform must be tighten really a lot to hod firmly the build plate itself (I?m not sure if this is normal, but
seems too aggressive to be correct)

Any ideas to try more?

Best regards

NOTE: attached the test files I used

Had the same issues in the beginning, so let me ask some questions:
What resin do you use?
What temperature has the room you are printing in?
Have you used any stuff on the print plate, maybe for cleaning? Do you have scratches on that surface of that plate?

Me got a lot of failed prints because I was using translucent resin and using the slicing options for default (Black or grey resin). You may need to increase (maybe double) the lighting time.
And I got some really bad prints because I tried printing in my garage because of the smell. The Problem with printing in your garage is the temperature. 4°C is just too less... So nothing sticked on my plate.
And a colleague of mine had used some sort of cleaner that prevented his prints from sticking in the right place.

Maybe your plate is not perfectly calibrated? here is the official way to do that.

Now I use the right lighting times, the right temperature (ok, nearly, it's about 18 or 19°C in my room) and never use sth. else than the plastic spatula on the plate. OK, IPA is the only cleaning detergent I use.
So maybe you can change sth. and test it.
Sorry, I did all the Try and Error myself.

[swordman]

Thank you for the info MistaBreed!

To be honest, I'm doing a lot of testing on my own too.

Let me start answering your questions:
- Resin : I'm using Elegoo black resin
- I have not used any substance for cleaning the printer or the build plate. I only Ethilic alcohol 99% (I can't find IPA...)

Now, the new results:
I have been able to print my test squares: stiking them everywheren even in the center.
The adhesio in the center is still kind tricky, but worked 2 over 2 times after my last test yesterday.

Before entering into how I calibrated my build plate, let me tell that I changed the FEP on the vat because myne was tearing near the corner where the frame is pushed into the vat. (I don't know if this has any impact on my rrent results)

For levelling, I followed the guide for another resing printer (not mentioning here since I don't know if it is allowed) but is called the "flint read method"
(requires to have enabled the Set Z=0 button though)
- put in the empty vat
- thighten it
- release the screw to allow the build plate to rotate (release all, tighten until start to grip, release the bare minimum to free it)
- manualy go to zero the build platform
- pull the holding nuts to stop the build platform from moving
- try to move the vat slowly and carefully to not scratch it, should be stuck
- manually rise the build plate untill the vat starts to move (in my case it took 1 full milimiter, maybe more...)
- when the vat is moving, I lowered the built platform and checked that the vad is stil moving, but a littloe bit than berely (thi si tricky, personal feedback here)
- set that as zero with the SetZ=0 button

After that, I have been able to print the tests
now I'm trying to print a couple fo tilted rooks but not sure... I will see

[DarkDust]

I had the problem that the very first print (test tower and some custom test objects) came out perfect but then the next about 10 prints failed. I then had one print in between succeed only to have them fail again, this time only on the left side of the build plate (this means: objects right side came out perfect but objects on the left stuck to the FEP).

Now my last five or six prints succeeded, so it seems I found the recipe to success at least for my machine. I'm using Elegoo black and white resins.

I slightly sanded the build plate with a coarse sandpaper to make it a bit less smooth. For this, I placed the sandpaper flat on a table and then placed the build plate onto the sandpaper with some circular motions. This way I can also be sure that the build plate is really flush/flat. I also added a bit of masking tape to the sides of the UV LCD, like many are doing. Don't know if that makes any difference, though; it's supposed to help prevent a vacuum between the FEP and the LCD.

I'm now doing this before every print (might be overkill; don't know yet):

• I zero level the build plate. I did this one wrong before! After removing the vat, I place a piece of paper on the Mars, loosen the two screws of the build plate, then press the button to lower build platform. After it has reached the bottom I tighten the screws while holding the build plate down. I've seen a video where it was explained that you should then switch to the 0.01mm setting and increase the height until you can pull out the paper while still getting some resistance. For me, that's raising the build plate by 0.02mm. Then I tap the Z=0 button. I missed this last step before! Ever since I do that my prints succeed.
  
• I also apply some teflon lube to the FEP. I spray it onto a soft paper towel and apply it to the FEP until no droplets can be seen. This is meant to help preventing the resin from sticking to the FEP. How much that is helping I don't know, I still get to hear the typical "clicking" sounds of the resin coming lose of the FEP when the build plate is raising after each layer.
  

After each print I pour the remaining resin back into its bottle (through a funnel and paint sieve to filter out cured bits of resin), then clean the vat with 99% IPA. I only skip this if I'm immediately doing another print with the same resin and the print came out perfect.

Between the all-prints-fail and all-prints-succeed periods I did experiment with the light settings but actually ended up with the values I was using from the very beginning: 50s for the first layers, 6 layers, 7s per normal layer. So I can least say the these are not factor in my case.