Build Your Own SLA/SLS

Technology: Continous Liquid Interface Production (CLIP)
Company: Carbon3D.com
Speed: 300 mm per hour compared to 60 mm for fast silicone release machines
Video: https://www.youtube.com/watch?v=23at9QglAm8
Scientific Article: http://www.sciencemag.org/content/early ... ce.aaa2397
Abstract :
Additive manufacturing processes such as 3D printing use time-consuming, stepwise layer-by-layer approaches to object fabrication. We demonstrate the continuous generation of monolithic polymeric parts up to tens of centimeters in size with feature resolution below 100 micrometers. Continuous liquid interface production is achieved with an oxygen-permeable window below the ultraviolet image projection plane, which creates a “dead zone” (persistent liquid interface) where photopolymerization is inhibited between the window and the polymerizing part. We delineate critical control parameters and show that complex solid parts can be drawn out of the resin at rates of hundreds of millimeters per hour. These print speeds allow parts to be produced in minutes instead of hours.
Patent: https://www.google.nl/patents/WO2014126 ... CCAQ6AEwAA
Financiers: Sequoia Capital, Silver Lake Kraftwerk, Baillie Gifford (Scotland), Fidelity Management & Research Company (U.S.), ARCHINA Capital (HK); Hydra Ventures (the corporate venturing arm of adidas), GE Ventures, JSR Corporation, Emerson Elemental (the environmental practice of Emerson Collective) and Reinet Investments
Money: $200 million to date


Opinions anyone!? Advantages, disadvantages!?

hahahaha, you posted as i was typing my post ^^

seems like the holy grail, and as i recall we discussed the oxygen layer here long time ago. Thoughts on the printer?
I think the claim about controlling exactly how much oxygen gets through and when is bs, it's simply a permeable platform exposed to normal air.
Or do you guys think the oxygen has to be forced through?

Cheers!

Continuous printing would be the final upgrade. LCDs and flexvat for size, and CLIP for speed and material toughness, that would really be something.

It might be that they're over complicating their explanations, and it's "just" an oxygen permeable floor. I would go even further and say it's a flexvat. You can clearly see two silver clamping knobs on left and right sides that could be used to raise the tensioning mechanism, and sheet layers of vat construction that would clamp the stretched floor material. Unless the knobs are used for leveling.

Here, something like this. UV transparent down to 300nm, 25 microns thick, 90 cents per sheet:
http://www.usascientific.com/breathe-easy-film.aspx

Of course, with 40 million raised in funding, they could go to any chemical manufacturer and have them make something specific to their needs.

I think that one of the most important part of the Carbon3d is the software for projecting that piece in 3d to images, probably uses a slighly morph or blending between images/slices, instead our traditional 2d projection slice.For starting to investigate we need probably a simmilar way to project it,(We need your help PacManFan!!!!) and when is ready, start to test new techniques and materials with a new compound for the VAT, I think that the flexvat or teflon is not good idea, because the force effect suction doesnt permit to fill the small build space between vat and build plate with more resin.To be possible that technique, the curing area zone needs to be clearly separated from the VAT.

Oh no, I didn't think FEP/teflon or any kind of already used flexvat. It has to be oxygen permeable for 100% force free release, that's the key to continuous printing.
That's why I put a link to the gas permeable sheet above.

As a non sticking layer they use a fluorpolymer, e.g. Teflon AF 1600 or AF 2400.
The AF 1600 and AF 2400 have a high oxygen permeability and cost 1800 dollars per 25 gram.
The speed of the object's formation depend on the viscosity of the resin η, atmospheric pressure , the height of the gap between the object and the bottom of the chamber h, and the linear dimension L of the object's bottom surface. In the patent, simple calculations are performed to estimate the speed using the theory of viscous flow between two parallel plates. The time τ which is required to fill the gap shown on FIG 7 is given by the equation:
theta ~ (L/h)² * eta / Pressure

For silicone, the oxygen permeable layer is in the order of microns, so h= 2.5 micron (source: Dendukuri, D., Pregibon, D. C., Collins, J., Hatton, T. A., and Doyle, P. S. (2006). “Continuous-flow
lithography for high-throughput microparticle synthesis”. Nature Mater., Vol. 5, pp. 365–369)
They state they can increase the oxygen inhibiting layer to 100 micrometer, so h = 100 micrometer.
For the other parameters, they use the values:
Pressure is atmospheric so Pressure is 1 Bar
L is object length, e.g. 100 mm
eta is resin viscosity is 100 cPoise

Using the equation mentioned above and the larger h, they claim they can significantly increase the build speed. An alternative to increase the build speed, would be to use an oxygen rich environment and a large pressure in the build chamber, they mention 10 bar for an embodiment see figure 8 in the patent.


Discussion:
I guess, if you buy this fluorpolymer film, and simply use this film instead of the other films most DIYers have been using, you should be able to significantly increase the build speed.
Are there any cheap alternatives to Teflon AF 1600 or AF 2400!? So cheap highly permeable layers of silicon or porous glass?!

The software needs to project every image without blank frame intersections, and needs to be moving in z at very very low speed at constant velocity without stops, that is possible with creation workshop? any expert in mathematics to know the average measure movement in z??(for example,60 microns/minute)...... any ideas?

From the patent text:

"A drop of ultraviolet (UV) curable adhesive was placed on a metal plate and covered with 10 mm thick plate of TEFLON® AF fluoropolymer (a amorphous, glassy polymer) as shown in Figure 5a, UV radiation was supplied to the adhesive from the side of Teflon AF as shown in Figure 5b. After UV exposure the two plates were separated. It was found that no force was required to separate the two plates."

That's the key right there. No force for separation. There wouldn't be any need for continuous image projection. Our long cycles come from having to move 200 layers up (and at a very slow rate to not brake the part or the vat) and then move 199 layers down. If you could just move 1 layer up, and project an image that alone would be a huge time saver. Bring in UV transmissive grayscale lcds for projection, and you have yourself a "continuous" 3d printer.

Another revealing part:

"The chemical phenomenon which describes the observed behavior is oxygen inhibition of the radical polymerization reaction. In particular, Teflon AF has a very high oxygen permeability coefficient. Constant supply of oxygen through 10mm think Teflon AF is sufficient to prevent a thin layer of acrylate adhesive from polymerization. The thickness of uncured adhesive layer in the above experiment was on the order of 10 microns and it can be increased or decreased by varying the amount of photo initiator present in the adhesive. "

Ha! There you go. Tensioned or what we call FlexVat, using Teflon AF 63,5 micron sheets:

"a build plate comprised of 0.0025 inch thick Teflon AF 2400 film from Biogeneral clamped in a window and tensioned to substantial rigidity with a tensioning ring"

Looks like someone might have been reading the forums?

Anyway I don't know how these patents could hold up legally. Isn't the B9 creator the first one to use oxygen permeable vat floor? And it's open source so that's public domain. Doesn't really matter to us anyway as you're allowed to make anything patented, for personal usage. The tensioned vat designs is also published here so that's public domain too.

Someone better call them to get a quote. I would be so in for a larger, 300x200mm sheet:
http://www.biogeneral.com/film.html