Reviews - Carbon3D demos revolutionary 3D printing technology (video)

[HEXUS]

"Game-changing" 3D printing process is said to have been inspired by Terminator 2.

Read more.

[Biscuit]

WOW!!!!!
That's just.... wow....

[TheAnimus]

So what is the difference between this, and normal sterolithography?

[Biscuit]

So what is the difference between this, and normal sterolithography?

It gives you a rough summary in the article:

"It works by projecting beams of light through an oxygen-permeable window into a liquid resin. Working in tandem, light and oxygen control the solidification of the resin, creating commercially viable objects that can have feature sizes below 20 microns, or less than one-quarter of the width of a piece of paper," Phys.org explains. By allowing the formed photosensitive resin to cure in the process, this allows the printing to occur in three dimensions at once.

... stating that his method could potentially be up to 1,000 times faster. DeSimone added that most objects created by 'traditional' 3D printing methods are mechanically weak because of the layer-upon-layer structure.

[TheAnimus]

It gives you a rough summary in the article:

"It works by projecting beams of light through an oxygen-permeable window into a liquid resin. Working in tandem, light and oxygen control the solidification of the resin, creating commercially viable objects that can have feature sizes below 20 microns, or less than one-quarter of the width of a piece of paper," Phys.org explains. By allowing the formed photosensitive resin to cure in the process, this allows the printing to occur in three dimensions at once.

... stating that his method could potentially be up to 1,000 times faster. DeSimone added that most objects created by 'traditional' 3D printing methods are mechanically weak because of the layer-upon-layer structure.

That sounds exactly like sterolithography?

Things like the Form-1



However, yes, this does appear to be more accurate, and faster, but it still strikes me as just a refined sterolithographic process.

[shaithis]

It gives you a rough summary in the article:

"It works by projecting beams of light through an oxygen-permeable window into a liquid resin. Working in tandem, light and oxygen control the solidification of the resin, creating commercially viable objects that can have feature sizes below 20 microns, or less than one-quarter of the width of a piece of paper," Phys.org explains. By allowing the formed photosensitive resin to cure in the process, this allows the printing to occur in three dimensions at once.

Wow...I saw this tech on "Tomorrows World"......now considering how long ago that was taken off air, I am surprised it's only coming to retail now.

I am sure the one I saw 15-20 years ago wasn't as good but still they managed to make a ball inside a sphere.

[Biscuit]

I think the difference from typical Stereolithography would be that it uses a concentrated single moving beam of light, this uses a light projector to draw the whole layer at once.

The video you linked does look like very similar technology to this rather than the typical 3D printing tech thats about on the market.

[TheAnimus]

Do you have more information about that projector? I mean, technically an emitter with a reflector being moved IS a projector. I can't imagine that a putting some liquid crystal over the top as a mask would deliver the accuracy required for the precision they quote.

It's also nothing that stereography is a fairly typical technique. The MakerBot and the like extrusion printers have always been a poor mans version when it comes to it, because it adds layers, rather than a continuous body, they are typical only because of cost at the low end.

Thing is, the speeds quoted are still impressive, I'd just wish they told us what was revolutionary, and cut out this terminator bull****.

[Biscuit]

Do you have more information about that projector? I mean, technically an emitter with a reflector being moved IS a projector. I can't imagine that a putting some liquid crystal over the top as a mask would deliver the accuracy required for the precision they quote.

It's also nothing that stereography is a fairly typical technique. The MakerBot and the like extrusion printers have always been a poor mans version when it comes to it, because it adds layers, rather than a continuous body, they are typical only because of cost at the low end.

Thing is, the speeds quoted are still impressive, I'd just wish they told us what was revolutionary, and cut out this terminator bull****.

I have nothing more than what in the article and I'm not expert by any means, I was just very impressed by how quickly it made such an accurate product compared to other 3D tech that I have seen.

Perhaps this article on RT gives a better description?

[TheAnimus]

Ah sorry figured you knew more about it by your enthusiasm, I'm not that impressed tbh, mostly because this is marketer speak, which I hate.

For instance, the ember 3d, which has landed in the hands of a chosen few, and is for pre-order today, has an accuracy that is 10 microns, to this 20 microns.

The only thing so far, that I've not seen on every sterolithographic printer out there today, is this 'oxygen permeable window' at the bottom. However, I gather resin trays are kind of consumable items, so I don't know what this means long term, but I doubt it would be an exclusive thing. I am left, just to purely guess, as someone who's ill informed on these matters (don't own one, can't begin to justify buying one...) that they can speed up the hardening process, because their window allows more oxygen to be there at the 'forming face'. If so that's really cool, but they should actually talk about that. Not make some references to movies, which it' can't begin to manage.

[edzieba]

As far as I can tell, it's standard stereo Lithography (a bunch of other 3D printers have used DLP projectors before, including DIY versions), with the addition of a vaguely described process somehow involving Oxygen that allows for much faster print speed. And a whole lot of marketing guff about not printing in layers (It also prints in layers. And depending on the process used layered printing does not necessaruly have any detrimental effects).

[Whiternoise]

So what is the difference between this, and normal sterolithography?

http://3dprint.com/51566/carbon3d-clip-3d-printing/ has a better description. They've pretty much done away with conventional layers, which is a massive breakthrough. Just look at the microscope images.

I'm very impressed with the lack of support structures on that ball. If you tried to print that on a Form 1+ (we have one at work) without supports you'd get a mangled mess in the tank. It's a bit of a con really given how much hype there is around it, the resolution is great, but you have to be very careful about the orientation you print in so that you don't get support points in obvious areas. These must then be filed/oiled down otherwise the part looks crap.

This looks a lot better.

[Whiternoise]

Ah sorry figured you knew more about it by your enthusiasm, I'm not that impressed tbh, mostly because this is marketer speak, which I hate.

Ok, having actually read the paper now..

Essentially if you let oxygen reach the resin, it can't cure properly (it disrupts polymerisation). So they have this big contact lens membrane thing at the bottom of the tank which lets a small amount of oxygen through. They can combine this with the light intensity and resin properties to vary the thickness of the 'dead zone'. This is the crux of their innovation. In most other respects, this is the same as any old stereolithography printer.

They use a DLP chip to generate the pattern, I guess one of TI's rather expensive digital mirror devices. Lateral resolution of <0.1mm is claimed.

Although they haven't exactly gotten rid of layering, clearly the part must still be sliced, what they have gotten rid of is the repetitive 'dip, remove, dip, remove' process. In traditional UV printing, when you expose the resin in an oxygen-free environment, it sticks to the build platform. For the Form 1+ (I don't know about others) this is why you need a peel stage after each exposure. The bottom of the Form resin tank is optically clear silicone. The resin gets cured onto this silicone and then the part gets ripped off, basically. And of course you have problems with surface tension; if your part isn't well designed or oriented, you get immense amounts of suction and the part breaks (think trying to remove a wet coaster from a table). Another problem with this is that once you've cured the layer, you need to lift the part to let the new resin get in under it. As they point out, the peel stage takes a few seconds and if you're printing in 25µm layers, with a few thousand slices, most of your time is spent peeling.

If you can stop this hardening at the window, you don't need to keep refreshing the resin, it gets sucked in via surface tension automatically as the part is lifted continually. Again they haven't removed layers as such, but their method allows them to have simply whack up the refresh rate of the projector in order to get very smooth finishes on the parts. This, then is the fundamental difference, CLIP allows you to print without a specific resin refresh stage.

The membrane itself is made of Teflon AF 2400 (no idea either!). The researchers found that the dead zone depends on three factors, the photon flux (how bright the lamp is), an absorption coefficient and the resin curing dosage (how reactive the resin is). If you bump up the flux or the absorption coefficient, you get more free radicals in the resin. Oxygen + free radicals = peroxides, this means no curing. If you add oxygen into the mix, through the membrane, then the oxygen gets rid of free radicals for a short distance into the resin - the dead zone.

Then there's a bit of discussion about how they can vary the dead zone size and how it affects resolution. It depends on a few things, e.g. how absorptive the resin is. If it's low, then you have to wait longer for each slice as otherwise you'll start double exposing layers. They managed to get the zone thickness down to 20-30µm before parts began to stick to the window. They also admit that build speed starts to get more complicated with bigger parts as you start to depend on things like suction (how fast you can refresh the resin), resin viscosity and optical depth.

What concerns me is the same as with the Form - the tank is a consumable and the Form is already quite expensive for this ($50 replacement!) especially when resin isn't exactly cheap either. Not so much of a problem for a business and it's still cheaper than prototyping in metal, but for consumers it's a problem if you have to buy a new membrane tank every time you change resins.

DOI: 10.1126/science.aaa2397

[Biscuit]

Thanks for taking the time to explain that, much appreciated!

[TheAnimus]

Thanks for doing that Whiternoise, Hexus should pay you to write for them (DR if your reading ).

The press release mentioned so little of this.

So basically the membrane on the bottom of the tank, allows oxygen to get to the resin as it's been exposed to UV, meaning it cures faster, because then, it doesn't have to retract the forming resin and re-dip, it's not only faster, but still continuous, much like a concrete slip-form structure is?

I kind of gathered that window was the breakthrough, but didn't realise it meant that they didn't have to extract the form out of the resin tank, to let it harden.

That is rather neat, and I definitely can see the speed improvements being enough of a reason alone to consider this for business applications.

Out of interest, what do you use the 3d printer for?

[Whiternoise]

Thanks for doing that Whiternoise, Hexus should pay you to write for them (DR if your reading ).

The press release mentioned so little of this.

So basically the membrane on the bottom of the tank, allows oxygen to get to the resin as it's been exposed to UV, meaning it cures faster, because then, it doesn't have to retract the forming resin and re-dip, it's not only faster, but still continuous, much like a concrete slip-form structure is?

I kind of gathered that window was the breakthrough, but didn't realise it meant that they didn't have to extract the form out of the resin tank, to let it harden.

That is rather neat, and I definitely can see the speed improvements being enough of a reason alone to consider this for business applications.

Out of interest, what do you use the 3d printer for?

Not quite, maybe I explained badly (don't hire me yet!)

Normally you'd have:

Laser ======> | Window | Silicone | Curing zone | n-1th layer

The curing zone height is equal to the layer thickness. The nth layer gets stuck to the silicone and has to be peeled off each time. The peel process unsticks it and replenishes the resin.

You don't want oxygen if you're designing a resin printer, it slows the curing process*. So the oxygen inhibits the layer in contact with the membrane from curing. The dead zone is always liquid. When you shine the laser through, you're curing the layer of resin just above it without worrying that you'll cure the resin at the membrane. With CLIP you have:

Laser ======> | Membrane | Dead zone | Curing zone | n-1th layer

Then as you draw the structure up, the dead zone gets replenished and provides fresh resin to be cured. The dead zone is a few tens of microns and as you get further into it, the oxygen level depletes and you can cure it (the nth layer).

* It occurred to me that in the paper they tried with Nitrogen and that doesn't have any inhibition effect, so you don't get this problem with normal 70% N 'air'. I think the membrane only allows oxygen through (though maybe I'm misinterpreting).

We use ours for prototyping, small enclosures, mounts, stuff that we'd normally get made in metal. We get most stuff done from 3dprintuk who use laser sintering, but they're a bit pricier - you pay for the bounding box so you need to be a bit clever about how you arrange your prints (printing a non flat-packed box is an expensive mistake). Laser sintered parts are pretty great, you can tap holes in them for screws and they're quite strong. Weird texture, like an extra strong mint and the advice to clean the unsintered dust off is "put them in a dishwasher". I complain that it's expensive as a consumer, but as a business £40 is dirt cheap when the CNC shop wants to charge you £1000 (true story).

The Form 1 is cool, it looks good in the lab, but really the technology just isn't there yet. When it works, the results are excellent, but you have to have patience. We wouldn't trust it for an urgent project, put it that way. It's a shame because it really is lovely hardware.