Solidator Vat Release Patent

[AndersonTa]

The FEP is pulled taught and sandwiched in place. There is constant air flow, in and out, so there is no pressure build up for inflating or deflating of the FEP surface. As for why there are no air bubbles, its very little air passing through, just enough to negate a vacuum. That's also why you don't see resin leaking out. I had wondered the same but after talking with folks that have seen/used the Solidator, that's how it is apparently. SCIENCE!

The gap is also very small, apparently 1mm.

As for the liquid pump and inflating method, wouldn't you get optical distortion when the light tries to pass through?

[AndersonTa]

Also read section [00022] in the patent I linked. That explains the release method...though its in patent/legalese language.

[Helmi]

Interesting method. Though i don't have any experiences with printing yet (first printer still to build) from the description in the patent i could imagine that they just use something like a silent membrane air pump to keep the atmospheric pressure within this cavity between the film and the bottom of the vat just a little bit higher. That shouldn't bee too hard and to expensive.

Whatever liquid you use in this space it could be crictical to the UV light, right?

[erenaud]

I believe that there is glycerin underneath the teflon fep film.
the glycerin can pass through the fep film when the cured layer is lifted with the build platform,
and flow back underneath the teflon (because it is heavier than the resin) once the freshly cured layer is released.

does that make sense ?

[keyanzhao]

"To facilitate release of the cured material of the film, it is advantageous if the receiving means comprises a semipermeable
film, which is stretched over the receiving surface, between the receiving surface and the semi-permeable
film, a cavity is provided, which is connected to a feeder , which is used to supply liquid or gas-like material in the
cavity. The semi-permeable film is impermeable to the photo-curing material but permeable to the supplied liquid or
gaseous substances. The semi-permeable film may be formed for example as transparent FEP (Fluorinated
Ethylene Propylene) film. These substances act as inhibitors for the polymerization in order to prevent
polymerisation of the contact surface of the film. In the preferred embodiment is when the inhibitors in acrylic-based
resins to oxygen or atmospheric air. In this case, there is no direct contact between the material to be consolidated
and the receiving surface. The liquid or gaseous material is pumped at atmospheric pressure or with a slight excess
pressure in the cavity, preferably continuously. To ensure that no created too much pressure a relief for the
respective medium is provided."