Sorry to dig up such an old project.  Elegoo recently started putting Fresnel lenses into their MSLA printers to collimate the UV.  It had been the first I'd heard of a Fresnel lens used this way in an MSLA LCD printer, but here they are in the "setup" illustrations you posted six years ago.  Are those your illustrations?  Did you actually install a Fresnel in the uTopia Printer?  (I didn't see one in the component list, couldn't confirm either way from the photos.)  An often-ignored weak point for so many of the budget printers on the market these days seems to be the quality of the UV source; I'm curious about the types of solutions out there for structuring the UV, and how well they work in practice.  My understanding of Fresnels is that they don't typically give great precision for imaging applications; but I wonder if that applies in this case, or if it does then to what degree it depends on the quality of the lens and how cost-efficient it may or may not be to use higher-quality lenses.

If you have thoughts or any resources on the topic, I'd be very curious to see them!

Hello All,

could you please tell me how can you provide uniform light?I mean, if we print full table for same model, can we get same weight for all(like are the weight of print in the corners is same weight of print in the middle?)

In laboratory we use a diffuser but it's to small for 3d printers you can try stencil-film:
https://www.youtube.com/watch?v=rRaZd_OxKVU

Hi, which firmware is used in Arduino ? is it Marlin or Soomthie 

Hello,
I am new in this domain and i have a curiosity, how is sticks the part on the table?
Sorry for bother you.

may i ask how did you make the UV pass through the Lcd Panel, 

From what i know lcd panels don't pass UV 

Sebastian already tried, Display 7 ...At070tn92 -

TFT 800,480.

PS: Yesterday I called my 100w uv led almost went blind .rsrs 

Sebastian, you know if this works with screen ipad 3? I have here led uv 400nm 100w.

I do not know ... We have to try.

How exactly do I need to connect UV LED driver ?

Driver out to LED input or driver in to LED output ?

Hi @newbie,
From the LED driver output to "LED input" and the LED wires to "LED output".

Hello

 
Sébastien stopped the project?
Just get some parts for my printer.
retina display ipad 3, led 100w 400nm, LED driver.

I am following your project and would like your support and possible!
my email is msilvagibin@gmail.com

Hi msilvagibin,

The project is not stopped, but I have not much time to work on it now. I try to open a FabLab in my city and work on several other Open-Source projects at the same time...

Nice project .

Thinking about the screen why not use an old android phone that you can display and control remotly (need to open the phone in half for correct usage but can be a cheap alternative to a LCD + Driver (and regarding for LG G3 with broken digitizer for <50€ for an ~500DPI would be a great deal) i am going to look into my old nexus 4 for see if i can do something

Great job, nice to read and to get informations for my project! 

Which Resin do you use for this? 

Only one thing in the last project you use a fresnel lens but where you buy it? and under the lcd that you use you remove only the backlight or all the films?

I removed all (amovible) filters on the LCD. 

The fresnel lens can be found on ebay. Try to find fresnel with a focal the closest to the distance between the LCD and the LED.

Hi Sebastien,

Would you please let us know how could you remove LCD filetres,
There is one aluminyum filtre back of LCD.
In order to get full visible LCD screen
We must remove but it is well stick on lcd !!

Is there any solution

Hi,

thanks for reply, yes we can collaborate together for best result! :) Give me your contact so we can speak for new project! This is my email geometra.gaspari@live.it

I'm not sure I understand. Why complicate things by adding a mobile element? In addition, the exposure time will be longer.

Hi to all,

i'm working on my 3d sla printer, i see this project and i'm entusiastic for your:
LED's array setup (medium/big screen)
I want to use an ipad 3 display retina for my printer..
Is possible to know where i can buy the components please?
- correct fresnel lens
- correct diffuser
- correct leds array

- correct head sink

I need to remove only the backlight panel or also the films under the lcd after remove the backlight?

best regards

Sorry I do not have all information at this time, you have to test by yourself. I have made only one prototype. The next (with LED array and 5.6"LCD) is coming soon with the rest of the instructions and more details. 

Be patient (or do it yourself), I do this in my spare time. 

P.S: Contributors welcome :)

The OLO is a gadget at ~600$ (99$ + ~500$ for the phone) powered by AA batteries and working with visible light resin... the curing time is long and your phone must  be in airplane mode with wifi and alerts turned off ! Definitely not for professionals... and BTW not Open-Source.

You're being a bit dramatic! A used smartphone is only $100-$200 for a last gen high end Android. You can get a perfectly  usable  mid tier last gen for under  $100. 

I am amazed at their dedication , was seeing a material using retina iPad screen using UV 400nm to 420nm with 5% absorviçao it would be a little more per layer cure time .

Hello why not use ipad screen?

That because I have several old LCD I want to use [https://goo.gl/photos/CBWuzQbK6VCCLjp67]. But you can use whatever you want. This project is more a concept than a finished product, a bit like the RepRap project, anyone can make improvements.

Do you have any pictures of cleaned (but not otherwise post processed) parts? I'm curious what the results look like!

Also, what was the motivation behind making your own slicer? Have you looked into NanoDLP? it uses a raspi, and can take care of all the slicing, motion, and projection. All you need to do is add the motor controller. (I've had a lot of luck using it with a projector, and it's convenient to not tie up a computer, or accidentally interrupt a build when printing)

Sorry I do not have many pictures of finished parts, some one in the gallery : https://hackaday.io/project/12791/gallery#019e9a1922dcc0d8d0d3e338b3948e11 (but more will come soon).

Three reasons for the slicer : First to learn; Second for the fun; Third I contribute to the SmoothieBoard project (http://smoothieware.org/) an Open Source Hardware CNC controller board with an embedded web server, so no need to rpi or anything else, just upload SLAcer.js (js + html) on the server and you have a standalone machine that is accessible through a web interface.

P.s: I apologize for my bad English.

Maybe I'm an old fart.  normal desktop displays used to come out to around .25mm per pixel.  I'm not used to the displays for phones that have high res and small size. .1 mm sounds like it might be almost enough. What layer-height are you using right now? Could you slice more layers and go to a more continuous process? at 10 FPS you'd get 70 times higher Z-resolution than what you have now....
For the resolution... I did the math and got... 5.6*25.4/sqrt(1280*1280+800*800) = .09423381153256540211 the same answer as you. 

If you strip the RGB filters, you should be able to get 3840x800 resolution by the way. Awkward to have non-symmetrical resolution., but better than .1x.1.. 
Have you checked that the polarisers, and the lenses work at UV wavelengths? I guess you have: "it works"... :-) 
(But if the lens absorbs 80% of the UV, you can get a 5x print time improvement.... )

For now just tested at 0.1mm, but the Z axis resolution is 0.00125 mm/step with 1/16 microstepping. 

To be honest, I have not tested the proportion of uv captured by the lens. But I'll will test soon without the condenser to see if it makes a difference.

To be sure: I don't THINK that it absorbs 80% of the UV, but it COULD be. We humans are more or less used to "something is opaque" or "something is transparent" and that we have a good idea about which is which. But we have absolutely no intuition for wavelengths "outside our sensory bandwidth". For example I know that glass is opaque for 10 micrometer infrared. 

Haha! ~10 FPS nicely translates to 1 microstep per frame... The amount of data that your slicer needs to produce however is enormous! (If my estimate is good, about 9 FPS results in the same exposure time as now). 

See 4:30 for an example of a counter-intuitive IR transparency. (the title and the woman in the preview frame are clickbait. No naughty parts are seen in the video :-) ). 

@r.e.wolff Just tested without the condenser lens and the result is not great... apparently the lens does not filter UV.