Print does not detatch from the FEP film  

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fooforge
(@fooforge)
New Member

Hello everyone,

I have received a Prusa SL1 last week and had little trouble assembling it. My first two test prints, however, have failed, and I'm a bit at a loss what to try next. The raft and the first few layers have printed just fine, but when the printer gets to the actual model, it seems to attach too strongly to the FEP film resulting in the model getting ripped apart eventually.

I have tried printing the model twice by now and did a quick test of a 60x60 first layer square that was proposed to try by @chocki in this thread in between the two prints. The square has turned out OK. If I hold it against the light, I can see some bubbling, but otherwise the print is fine.

Layer height is 0.05mm, exposure times are 35 / 7.5 / 1s. Worth noting is that the same model prints on my Formlabs Form 3 just fine.

[gallery ids="38638,38626,38629,38623,38635,38632"]

If the above gallery link does not work, here's a link to the same content on Imgur: https://imgur.com/a/OTDgxNk.

A few questions:

  1. What could be the reason for the model sticking to the FEP film so strongly?
  2. How can I prevent that from happening?
  3. Any good tips for removing the leftover resin from the FEP film without damaging it?

 

Thanks in advance!

Regards,
Mike

This topic was modified 8 months ago 2 times by fooforge
Posted : 06/07/2020 1:18 pm
JoanTabb
(@joantabb)
Moderator

Hi Mike,
Do you use a Pad, under the supports? (to increase the surface contact with the build plate)

try increasing the duration of the first layer  exposure to about 50 seconds to give a better bond to the build plate, 

for removing the patch off the Fep film, (it's safest to empty the resin reservoir first)

I then take a clean microfibre cloth and rub it gently across the underside of the Fep film, pressing gently up, 

you should be able to feel the  stiffness of the solidified resin as you press against the film, work the cloth across edge of the stiff resin, and it should part from the FEP film, once this occurs you can east the edge of the plastic spatula under the edge of the hardened resin, and lift it out

(I have to admit, I usually do this with the resin in the tank... but that is a risk you have to evaluate. )

regards Joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 06/07/2020 2:05 pm
fooforge
(@fooforge)
New Member
Posted by: @joantabb
Do you use a Pad, under the supports? (to increase the surface contact with the build plate)

try increasing the duration of the first layer  exposure to about 50 seconds to give a better bond to the build plate, 

for removing the patch off the Fep film, (it's safest to empty the resin reservoir first)

I then take a clean microfibre cloth and rub it gently across the underside of the Fep film, pressing gently up, 

you should be able to feel the  stiffness of the solidified resin as you press against the film, work the cloth across edge of the stiff resin, and it should part from the FEP film, once this occurs you can east the edge of the plastic spatula under the edge of the hardened resin, and lift it out

Hi Joan,

Thanks for the swift reply! 🙂 

I was able to remove the object from the FEP film relatively easy with your suggestions. Thank you!

And yes, I'm using a pad. The pad itself and the first layers of support also print fine and attach to the build plate nicely. The problem starts when it gets to the first few layers of the actual object. Not sure if increasing the first layer exposure time from 35s to 50s would make much of a difference in this case? Could it be that it's just not enough supports to hold the object in place?

This is what it looks like in PrusaSlicer after slicing:

Regards,
Mike

Posted : 06/07/2020 2:49 pm
Bioluminous
(@bioluminous)
Trusted Member

@fooforge

I am a new SL1 user also. I have found that when I have this problem, it is sometimes solved by: in PrusaSlicer, in the 3D editor view (default view), right click on the object after importing it and select "Optimize orientation". It seems to place it at such an angle to reduce the stress on the supports. So far, this has worked well. Also, I am careful not to clean the FEP film with alcohol, using just some windex glass cleaner instead. I think this helps with making sure the FEP does not stick too strongly to the print (usually just where the supports meet the print). Let us know if this helps.

Posted : 07/07/2020 1:52 am
fooforge
(@fooforge)
New Member
Posted by: @oem

@fooforge

I am a new SL1 user also. I have found that when I have this problem, it is sometimes solved by: in PrusaSlicer, in the 3D editor view (default view), right click on the object after importing it and select "Optimize orientation". It seems to place it at such an angle to reduce the stress on the supports. So far, this has worked well. Also, I am careful not to clean the FEP film with alcohol, using just some windex glass cleaner instead. I think this helps with making sure the FEP does not stick too strongly to the print (usually just where the supports meet the print). Let us know if this helps.

This is extremely great advice, thank you!

Since my last post, I have printed another object, the calibration one from Prusa which also comes with a pad and support structures, and that has printed just fine. I'm not near my printers today, but will try out your suggestion tomorrow and report back once more. I am fairly confident though that this is the issue, so thanks again! 🙂

 

Regards,
Mike

Posted : 07/07/2020 6:04 pm
JoanTabb
(@joantabb)
Moderator

@fooforge

Hi Mike,

I didn't notice that you were getting parting. with the pad remaining on the build plate with the rest of the model sticking to the FEP, 

In this case, it might be too few supports or inadequate curing time on the main print layers Is your printer in a cold environment? this can affect curing time. 

try adding a little extra time to the exposure time...   and /or more supports

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 07/07/2020 9:44 pm
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