Sticking resin on the FEP film (flexvat)

[Hellenicopter]

Dear Support,

I have a problem with the FEP film (brand new) of my flexvat.

Even the first layer is getting stuck to it but it is well developed when I inspect it on the FEP.
When the plate is at the home position it is in contact with the FEP, no initial gap. Would that be an issue?

I tried to increase the exposure time for the first layers but the problem remains.
It happens with MJ SF and FTD IB resins that I tested. I tried aluminum building plates as well as custom acrylic ones, no difference.
My exposure time for the first 3 layers is 6s-10s but I can have the resin well developed in less than 2s (50 micron vertical and 80 micron in-plane resolutions).
Would a fast reaction of the resin create a problem with sticking on the FEP?

The peel move is relatively slow (0.5mm/s).

I am out of ideas. The FEP has been cleaned with a glass cleaner containing ammonia (standard glass cleaner).
Is there any risk of functionalization of its surface with such a treatment (I would file a patent in that case... :p) ? FEP is notorious for being chemically inert though.
Does the FEP that you sell have a "right" side (anti-sticking) and a "wrong" side?

The FEP I use I purchased directly from you.

Thanks in advance for the help.

Best regards

[mUVe 3D Admin]

Based on your description, it sounds like the resin isn't actually sticking to the build plate. The FEP material is really really non-stick and nothing should really cause it to degrade chemically either. So your ammonia based cleaner is fine for the FEP, though it's really bad for the acrylic. So avoid using it there. And no, there isn't a good side and a bad side or anything. Both sides are created equal as it's the same material all the way through.

I would try increasing your first layer cure time to something ridiculous like 30-40 seconds. Because you are using FEP there's no risk of burning or degradation. So any initial overcure will just help cement the part to the build plate. Your peel seems fine or could even be considered slow. Once you overcome this issue I would try increasing a slight amount depending on how large the part you're printing is. Personally I use about 1-2mm/s for the first 30-80 layers, then I switch to 12mm/s and it cuts printing time way down.

On my home lab machine and MakerJuice SubSF Red, I have 10 second layers, and a 60 second initial 2 layers. It's a huge number but the parts are always stuck to the build plate!

mUVe 3D Support

[Hellenicopter]

Hi,

Thank you for your quick answer.
Indeed the first layer doesn't stick to the plate (whether the plate is out of aluminum or acrylic).

My projector is customized to cure the resin very fast by letting 90% of the light around 400nm to pass.
For a 50-μm thick layer I have seen that exposure time of 1.5-2s is enough.

I suspect that maybe the reaction happens too fast for the resin to build strong bonds with the plate.
Nevertheless, I will try longer times as you suggested hoping that the problem will be solved.

Thanks again for your help.

Cheers

[Sebastiano lo sauro]

Hellenicopter,
use 45 seconds for the first 4 layers problem solved.
projector uses and which changes you made to have about 400 nm?
Thank you.

[Hellenicopter]

Hi Sebastiano,

Thanks for the tip. It doesn't seem to work for me so far. With Sylgard 184 on the glass vat I could get it stuck on the plate in less than 10s (maybe 6-7s if I remember well - I don't keep a detail log, not a good practice when experimenting).

Regarding the modification of my projector: this is experimental and if you have a Viewsonic PJD7820HD you don't really need it. My projector is a different model and filters better the shorter wavelengths and I needed to boost it a bit. The key component that needed to be changed was the lamps hot mirror. You can see more details in this thread.

Cheers