Super Fast ‘Membrane Based’ 3D

General discussion of topics that don't seem to fit anywhere else.
anthony.julu
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Re: Super Fast ‘Membrane Based’ 3D

Postby anthony.julu » Sat Apr 04, 2015 3:45 am

Sid, i bet you're getting more enthusiastic about LCD printer after seeing the prismlabs' machines. I know I am... :D

Hugues
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Re: Super Fast ‘Membrane Based’ 3D

Postby Hugues » Sat Apr 04, 2015 3:48 am

Sid, where did you get the connection with the titanium dioxide ? Maybe it has potential.

Re: PDMS, the Titan1 I'm using has a PDMS base with a FEP film on top. People have tried printing on PDMS directly, it works but become cloudy quickly.
Last edited by Hugues on Sat Apr 04, 2015 7:12 am, edited 1 time in total.

anthony.julu
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Re: Super Fast ‘Membrane Based’ 3D

Postby anthony.julu » Sat Apr 04, 2015 4:36 am

It is a well known unfortunate fact that PDMS gets cloudy rather quickly when bombarder with long exposure time. The B9Creator's forum is full of such reports. But it could be different when each exposure is as short as 500 ms, and if a typical print is done within under 20 minutes instead of 4 hours plus.

This will allow for more print cycles than before. I don't know, it just seems feasible to me..

Hugues
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Re: Super Fast ‘Membrane Based’ 3D

Postby Hugues » Sat Apr 04, 2015 7:11 am

To try

But it's the total UV radiation that generates the cloudiness. So if you manage to print faster because less up and down motion, the total exposure time of your part should not change dramatically, so the total UV that your PDMS sees is about the same, I think.

Edit: not sure anymore what i'm saying. If the cloudiness comes from the UV, then why the Titan1 vat does not become cloudy just because there is a FEP film above. The cloudiness must be coming because of the resin, or the cured resin in contact with PDMS, so then you're right, less time spent on up and down would make less cloudiness. I guess.

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sgraber
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Re: Super Fast ‘Membrane Based’ 3D

Postby sgraber » Sat Apr 04, 2015 9:38 am

Hugues wrote:But it's the total UV radiation that generates the cloudiness. So if you manage to print faster because less up and down motion, the total exposure time of your part should not change dramatically, so the total UV that your PDMS sees is about the same, I think.

Edit: not sure anymore what i'm saying. If the cloudiness comes from the UV, then why the Titan1 vat does not become cloudy just because there is a FEP film above. The cloudiness must be coming because of the resin, or the cured resin in contact with PDMS, so then you're right, less time spent on up and down would make less cloudiness. I guess.


The cloudiness does not come from the UV; it's a combination of resins "soaking" into the outer surface of the PDMS and causing micro-cracking/micro-tearing. See: http://www.instructables.com/id/Window- ... r-printer/
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anthony.julu
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Re: Super Fast ‘Membrane Based’ 3D

Postby anthony.julu » Sat Apr 04, 2015 9:39 am

I think cloudiness is the result of the resin's curing process, whereas longer curing time per layer instigates cloudiness more quickly.
With the elimination of any unnecessary movements, one can use thinner layers, say 20 microns, without sacrificing total printing time. The benefit is, for the curing of each layer, the chemical reaction may be less "violent" compared to thicker layers.
Of course this may not be true for slow resins like the B9 red/cherry. But knowing that you use FTD resin, which is a very fast one, I guess you can give it a shot.
Also i wonder, why use FEP film on top of PDMS?

Phife
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Re: Super Fast ‘Membrane Based’ 3D

Postby Phife » Sat Apr 04, 2015 10:46 am

anthony.julu wrote:Sid, i bet you're getting more enthusiastic about LCD printer after seeing the prismlabs' machines. I know I am... :D



Where did you see that the Prismlab machine is LCD based? Not 100% but im pretty sure Its a top down printer with a projector, not an LCD mask. The LCD they are referring to on their website is talking about the built in LCD at the top of the printer to display print information.

anthony.julu
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Re: Super Fast ‘Membrane Based’ 3D

Postby anthony.julu » Sat Apr 04, 2015 11:17 am

If you go to their site, and click on "template" button, you'll find "curing principle: LCD on top". So yes, it is a top down unit, with an LCD as a mask device.

And if you look at their claimed build area and XY resolution, you'll see that they're using 4K resolution for the 300, 400, and 600 series. Considering that a 4K projector costs way above $10,000, such a resolution would only be made possible (cost wise) by LCD approach.

I could be wrong, but I'm pretty convinced that it's LCD

Edit: even the Rapid200 uses 4K resolution. While the rapid600 puzzles me, the mask resolution seems to be 1.5 x 4K, which is unusual. I don't think there's any commercially available device with such a resolution

Phife
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Re: Super Fast ‘Membrane Based’ 3D

Postby Phife » Sat Apr 04, 2015 11:46 am

LCD on top means that there is an LCD screen at the top of the machine.. have a look at the pictures.

While I could be wrong, I cant see how you could project the image from a large 4k LCD onto a top down based machine. Light scatters very quickly after it passes through the LCD. Also, have you looked at the cost of 4K monochrome LCD's?! Also above $10,000

Anyways, I guess time will tell, but just from my experience with working with LCD 3d Printers, I really dont think this is one, unless theyve come up with some fancy new tech using special optics and custom LCD's.

anthony.julu
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Re: Super Fast ‘Membrane Based’ 3D

Postby anthony.julu » Sat Apr 04, 2015 12:25 pm

I did see the LCD in front of the machine. We both know it's the user interface of the printer. I don't think they would refer to that when they say "curing principle: LCD"

I'm not aware of any monochrome LCD with 3840x2160 resolution. So, unless they've ordered some custom made LCD, it's quite possible that they utilize RGB 15.6" LCD from 4K laptops