Hello World (skip the first two pages to go directly to the build)

I have to admit that I have not been active on Instructables for quite a while now, this because we (yes it is we now :D) have been busy developing a 3D printer. A 3D dlp printer to be exact, an open source high resolution 3D DLP printer to be even more exact.
We have now finished version 1.0 and now it is time to share our learnings with the rest of the world.

Why did we work on a 3D printer?
Well as you all know the world needs more 3D printers, more platforms for creation, more freedom. More possible ways to show your epic awesomeness in creation. And most of all the freedom to design and fabricate exactly what you need, when you need it without any barriers. In short 3D printers are awesome, you can never have enough 3D printers.

Why did we work on a 3D Direct Light Processing printer (DLP)?
3D printers come in many shapes, sizes and varieties. There is Fused Deposition Modelling, FDM for short this is the category the RepRap community largely falls in to. Your Makerbots and Ultimakers that use a heated nozzle through which a filament is heated and deposited on the desired location. There are various powder bed 3D print techniques, where the powder particles are selectively fused together with a laser or glued together with a printed adhesive. And there is a variety of photo lithography 3D printing methods.
In lithography light is used to cure a resin to become a solid, the nice thing with this process is that where the light does not shine on the resin it stays liquid.

We found that there are two main DIY 3D printer routes out there that are easily accessible, FDM and photo lithography.
When googleing the WWW we found that there are absolute tons and tons of FDM 3D printers out there all working on roughly the same principles all producing roughly the same results.

Next to that stereo photo lithography has until now only been made really accessible to the community only by one guy, Michael Joyce from the B9 Creator. This is an awesome achievement! For us this also means that the world needs more and different kinds of these projects to become really open source. Photo lithography is an very precise method of manufacturing, in the past feature sizes of 100nm where obtained. No idea how big this is in inches (sorry people from the USA) but I estimate that if you squeeze your fingers together the space between your fingers is slightly less than 100nm.
In other words amazingly small feature size. We would love to make very accurate 3d prints.
So we based our choice of what kind of printer to explore on the possible feature size, accessibility of materials, ease of manufacture and the fact that a relative few have walked this path before us.

Step 1: Basic design properties

Here are a few things to consider in the 3D printer:
I find that making lists like this before every new build really helps me and the people I am working with (it is "we" now) to come up with an effective design that really meets our expectations. This printer will be a prototype, we plan to build a cooler, better more advanced version in a later future. Hopefully to be completed at the end of 2013. And if all works out maybe we can even get to a kickstarter. (Dreaming freely here)

The printer must be,not in any specific order:
  1. Affordable.
  2. Open source
  3. Compact.
  4. High resolution.
  5. Compatible with a wide range of materials.
  6. Easy to use.
  7. Fast

The basic operating procedure:
This is how a Photo Lithographic 3D printer works. Photo Lithography is very simple, light illuminates the resin and the resin hardens.
To be more exact a quantity of light falls/shines onto the resin, if the energy quanta of that light is high enough it will induce photo polymerization of the resin.

First thing is to decide on a light source:
The key part in this is quantity of light energy or Dose, a therm that comes from the world of radiology.
The dose is divided in to three vectors as you will, namely photon energy, light intensity and duration of illumination, together giving the total energy dose. Usually in the UV curing of materials the dose is only measured for a specific part of the spectrum. The rest of the light will usually be reflected or absorbed and converted in to heat.
Only photons with a high enough energy will take part in the photo polymerization. This means that the resin that you will be using is the determining factor in the part of the light (electromagnetic) spectrum that we are interested in. Most photo curing resins will cure under the influence of UV light. Light with a wavelength of between 365nm and 420nm. 
Some resins also allow for curing with longer wavelengths but these are usually rare and expensive.

1) One of the things to consider is that in order to be able to print with a wide range of resins we would like as much UV in our light as possible. I will explain this in depth when designing the basin, mirror and anti stick coating. 

The other part is time of illumination and illumination intensity. The illumination intensity, or luminous flux is the amount of Photons per unit of time that is emitted by the light source.  The longer you illuminate the resin the deeper the light penetrates and the harder and thicker your printed layer gets. This is a very unique feature of stereo lithography where the illumination time is another factor to consider as this determines the build layer thickness.

2) The light source must be of high intensity so the illumination time can be as short as possible allowing for a faster build.
3) An other thing to consider is that the light source needs to be very controllable in switching from illuminating the resin to not illuminating the resin.

In the principle of photo lithography, what gets illuminated polymerizes and what does not get illuminated stays liquid. This means that our resolution or minimum feature size is determined by the minimum spot size.

3) The third parameter for our light source is that it must have the possibility to illuminate a spot that is as small as possible.

Googleing we found that there are two viable light sources/systems that will meet these demands. A blue/UV laser with nice optics to produce a small spot size and a Galvo Head or A DLP projector. A  Lasers are cool but to achieve a small accurate spot with a galvo system felt to us as going way over our heads. Since non of us has any experience in setting up a laser, laser optics and a galvo system. And having the guys from Form 1 as an example (patent issues), maybe one day we would like to offer the world a kit too. We decided to go for the DLP projector option.

There is a whole world of DLP projectors out there. 
A light source passes through a rotating colour wheel and falls on a surface with actuated micro mirrors. These mirrors in synchronization with the colour wheel decide when to either reflect light through the lens or deflect it to somewhere else. Together many micro mirrors form the image.
As from our considerations in the above we can easily state what properties we want our projector to have:
  1. high UV content (determines if the projector works to cure the resin)
  2. high light intensity (shorter cure time)
  3. high contrast ratio (gives a higher resolution with less light contamination)
  4. high resolution (results in a smaller feature size)

Last but not least we only have 1000euro's to spend on a beamer. So there is a financial limit too. I realize this is not a small budget for a decent projector, but if the project fails I can always watch a movie on it.  
In the end we decided to use an Acer 7077365 Acer H6510BD DLP FHD 1080p, with 1920x1080pixels. Which we ordered at a local store.

Having the light source sorted we can now decide how to use our light source in our 3d printer:

Wait who ho ho stop, yes I know we are just designing a 3D printer but lets do a quick google on resins (photo curing resins). We found that these materials aint cheap. So this cancels the top down approach option. In common stereo lithography the light source illuminates a pool of resin from above. As consecutive layers form the build platform sinks down in to the vat of resin. This means your work piece can only be as high as your basin is deep. This also means that no matter what the size of your build, you must always have a full vat of resin. Meaning that if you want your largest object that you can print to be the size of a shoe, you will need a constant volume of about 3L of resin in your tank. At 80 Euros per litre, there are always 240euros sitting in the tank.
To us this is a bit much. So bottom up it will be.

There are two reasonable configurations when considering a bottom up 3D DLP printer. We can either project directly onto our build area or we can use a mirror to have our projector at an angle in respect to our build area.

We chose to put our projector at a 90 deg angle and use a single surface mirror to project a crisp image on to our build surface.
This because we are aiming for a true desktop machine, something that really fits on our desktop and is as compact as possible.

<p>It shows that the youtube video is private. Please someone upload a video if anyone has already made one of this.</p><p>Regards Hemang Joshi.</p>
<p>Would be very helpful if you can provide a comparison and step by step guide for vertically attaching the projector.</p><p>Regards sudarahan</p>
<p>Hi I like your instructable. I'd like to know if there are any updates, since this one has been published a couple of years ago, already. </p><p>I'd like to point you to another project, of a 4k projector, wich uses a 4k lcd screen to form the image to be projected andan high power 200W led lamp.</p><p>(<a href="https://www.instructables.com/id/World-First-DIY-Real-4k-UHD-Beam-Projector/" rel="nofollow">https://www.instructables.com/id/World-First-DIY-Re...</a>)</p><p>What do you think about using this solution in a sla printer? Because, this would eliminate the need for a special mirror and the expensive projector.</p><p>Regards!</p><p>Angelo</p>
For the basin someone tried to liquefy acetil silicone using trieline, then apply a very thin layer on glass?I m pretty sure resin will not stick the silicone..what do you think?Could be work?
<p>I think you want a somewhat thick layer of Silicone so that it will be able to absorb some oxygen and create a better oxygen inhibited layer in the acrylate that contacts it.</p>
True...infact this work pretty well...the problem is the low duration...anyway i made a very thin film by simple silicone between 2 non stick films and some weight on it...pretty perfect result.
<p>I think that should work, as long as the silicone is flat and transparant enough</p>
<p>The software from Envision Labs is now $495. <a href="https://datatree3d.com" rel="nofollow">https://datatree3d.com</a></p><p>Still looking for the firmware update? Please post new location.</p>
<p>hello !please tell me <a href="https://www.instructables.com/files/orig/FR7/Q6ZJ/IGMLV7R8/FR7Q6ZJIGMLV7R8.zip" rel="nofollow">250mm_ball_spindle.zip</a> 安裝到Arduino的兆2560? </p><p>Help me ! thanks </p>
<p>may i know your timelapse how long time is that ?</p>
<p>Hello, i have some doubts about buying my dlp projector. I'd like to use it to manufacture jewelry rings, using castable resin. Is it possible with this DIY 3D printer? And if so, i was thinking to buy a benq Ms524b (Native Resolution: 800x600, 3200 lumens and Contrast: 13.000:1). Is it worh it?</p>
<p>Could you use aluminum for the sides of the resin tank and glass for the bottom?</p>
<p>I am having troubles with my printer. The sylgard lining has been tearing up or has been deformed by the prints. Running exposure time at 3.5 seconds and exposure time on the bottom layers is 5 seconds. Lift speed at 70. Anybody have any recommendations?</p>
<p>where do we enter the pitch information(for the z axis leadscrew)</p><p>in the arduino code(firmware) or in the software(creation workshop)?</p>
<p>Is there any alternative for sylgard 184? It is really expensive in Germany ...</p>
<p>Check <a href="http://www.ebay.de/itm/DOW-CORNING-Sylgard-184-Solar-Cell-Panel-Silicone-Encapsulation-Encapsulant-Kit-/271784460875?hash=item3f479dc24b:g:hw4AAMXQAx9RMRU2" rel="nofollow">ebay.de</a>, I got mine from eBay in America for a reasonable price.</p>
<p>Love this project! My friend and I are considering making the attempt to build one. </p><p>Would using large borosilicate or soda-lime glass petri dishes work instead of having to make a basin? Seems like you could just pour in a puddle of PDMS to coat the bottom. I've seen them up to 200mm in diameter and 50mm deep.</p><p>Thanks for sharing your project!</p>
<p>Just to follow up, fused Quartz/silica is the best. It has great optical transmission down to 150nm. You can get a 150x150x3mm <a href="http://www.aliexpress.com/item/Clear-quartz-glass-plate-150-150-3mm/32345401251.html?spm=2114.01020208.3.58.xboESt&ws_ab_test=searchweb201556_4_79_78_77_80,searchweb201644_0,searchweb201560_2" rel="nofollow">here </a>for much less than you can anywhere else. However you will be getting 4 extras, so put them up on eBay?</p>
<p>Soda-lime and Borosilicate are both &quot;okay&quot;, ideally you'd have a glass that can transmit UV down to about 250nm wavelength and doesn't have any attenuation around 300nm since most UV resins work best around 300-350nm. To make it your first time, don't worry it will work. Just keep in mind your limitation when buying the resin.</p><p> Here's the optical transmission data:</p><p><a href="http://www.sinclairmfg.com/datasheets/optical3.html" rel="nofollow">http://www.sinclairmfg.com/datasheets/optical3.htm...</a></p>
<p>Bloody amazing. You should be selling those.</p>
How important is the 0.7mm thickness on the b-silicate window? I am having a problem finding one.
<p>I hate to say this but it seems like none of the software links are working. Is there anyone who could help me get a link to the required software for DLP printing? None of the Github stuff exists.</p>
Hi, just made an other attempt to fix the links. <br>Unsuccessful for now, I will try to ad the files
<p>It's okay, I was able to get everything but the firmware for the arduino. I'll hunt around Pacmanfan's files for the firmware. </p>
You are awesome man. Im dying to do this experiment as ive built a One-Up, Two-Up, and a Prusa i3. This instructable is what ive been looking for haha.
<p>I can't seem to find the software for this. Do these links still work for github? </p>
<p>i need a workshop to buld this :) really want one</p>
Be creative you will manage
Hi, is it possible to use http://www.mrwatt.eu/en/encapsulation-kits/164-eva-film-encapsulant-1m-.html instead of using the sylgard 184?
<p>hello everyone!</p><p>I am having concerns about purchasing the sylgard 184.</p><p>As you can see, in the description of this item on ebay</p><p>(here is the link for it:</p><p>http://www.ebay.ca/itm/Sylgard-184-Solar-Cell-Pane...</p><p>says that it is actually water resistant.</p><p>If anyone has any ideas what should I do please let me konw.</p><p>Thank you so much!</p>
<p>so what if i got a high intensity uv laser pointer, not even a high end laser because if a dlp is doing it a high intensity uv laser pointer should do it. then made a 1000 mm x 1000 mm tub, and did a cheaper 3d printer xy axis under it, then just attached the laser pointer to that. then used the same z axies option. i would imagine you could make pretty large items fairly quickly depending on how quickly that laser could move, but that could all be set up in marlin software pretty easily? this would not preform as accurate and detailed but it would be very reliable and possibly very quick?</p>
<p>Thank you so much for your instructables!!</p><p>I would like to ask you some questions about the resin basin.</p><p>I am trying to pruchase some sylgard 184 on ebay.ca,</p><p>and the description for this product says that it is uv resistance.</p><p>here is the link for it:</p><p>http://www.ebay.ca/itm/Sylgard-184-Solar-Cell-Panel-SILICONE-Encapsulation-Kit-/130429284542?hash=item1e5e30f0be</p><p>Please do let me know if this is the right item to purchase or not, </p><p>and thank you so much again for your wonderful work!</p>
<p>Thanks a lot! It's very useful for me to learn 3D-printting!I wish that I can do it following your teching.What's more,I need also have own idea.That will be great.</p>
<p>Im just curious If i was to build say a cube would it have to be a solid cause if you did it with say 0% infill wouldnt the inside of that box be liquid resin would having it as a bottom up or top down change this any other peoples thought on this topic?</p>
No, it would print each solid layer just like if you were printing 0% (solid) inlay on a regular 3d printer in say pla plastic. It would still be completely solid.
<p>I think he's asking about a hollow cube. Would it be filled with resin if you built a bottom up printer as opposed to the top down one you have? after all, a bottom up one would drop the cube slightly, build the walls, drop, repeat, and finally build the top, leaving a cube full of resin in the basin.</p>
<p>Sorry I may have mixed up the terms. I believe smatt444 was asking about making a hollow cube using a printer that lowers the object into the basin to make the next layer.</p>
<p>Great project and in my opinion SLA printing is the future. Do you think that something like Acer X110P could work (2700 ANSI/800x600)? How the lower resolution will effect the printing process? Lower resolution = lower details + lower quality? Thanks in advance</p>
<p>I think the Acer X110P is a viable option, the lower resolution will result in a smaller build area. So if you set up your printer at 100microns x,y you will have a build area of 80x60mm, at 50 microns this will be 40x30mm x,y. </p>
<p>How were you able to get your projector to focus? Unless it is a short throw projector, most cannot project a clear image from that short of distance?</p>
<p>I am using a Mitsubishi XD221U, and in order for it to focus on a wall, it must be about three feet away from the wall.</p>
<p>I have seen a few people already trying (I am going to try it as well hopefully soon) a top down design when resin layer flows on top of salted water. Most of the resins are non-polar fluids, so they don't mix with highly polar salty water. Probably other polar - and non reacting with resins - fluids would do as well. <br>That way the only major flaw of top town design (huge amount of resin needed) is eliminated. And I don't really see any major pluses of bottom up - go for simplicity!</p>
Awesome!<br><br>Ok, I'm not putting you off here. Top down printing is awesome. But just for your consideration:<br><br>Well not only, I found top down printing over all a bit more difficult. Not every resin accepts the saltwater float method. But our main problem was the surface of the resin. Most resins are quite viscous, so every time you move you need to wait quit long for the resin surface to level out. Also your layer thickness is dependent on how well you control your liquid surface. <br>On top of that the large container does make a large mess every time you want to change resin or clean out the solids that can be created during printing. <br><br>Bottom up printing does have the VAT complexity. But we managed to fully overcome this. <br><br>All in all, just sharing my learnings, I hope this helps and helps you anticipate any future difficulty. If you have any questions regarding top down or bottom up printing please feel free to message me.
<p>Thanks for pointing out other issues of top-down projection!</p><p>I plan to overcome the top surface leveling with these means:</p><p>- warm up the resin slightly to lower its viscosity,</p><p>- aim for continuous printing (similar to what <a href="http://www.gizmo3dprinters.com.au/" rel="nofollow">http://www.gizmo3dprinters.com.au/ </a> does) and with top down it is a bit easier than with bottom up, as you don't need an Oxygen permeable bottom of the VAT. When printing in continuous mode you don't go down-up-down with platform, so you don't disturb the top surface that much - and you go much faster ;-)</p><p>- if needed use a wiper of some kind. I also think about either an acoustic wave or a side edge air blower to clear the surface.</p><p>Of course this is just a conceptual analysis, that needs to be verified in practice - which I hope will happen soon!</p>
<p>Very inspiring Tristram! Because of your post to Instructables, I am well on my way with my version. Just want to say thanks for the inspiration! I've been at it since last June. I'll add a picture when done. I probably have 1 or 2 more weekends.</p>
<p>If you are in the Netherlands, you have missed FunToDo resins. We have no VOC's in our resins. We have various blends: Castable, Industrial and Standard. starts at &euro;45,- p/kg. We have distributors all over the world where you can order at local shipping costs and no import duties. www.funtodo.net</p>
<p>is it needed to replace lamp of projector with uv lamp? Or that Acer projector has the uv lamp in it? </p>

About This Instructable




Bio: Live to build
More by TristramBudel: 3D DLP printer kit assembly and calibration Impresora 3D DLP de alta resolución !CASERA¡ (impresora estereolitográfica 3D) DIY high resolution 3D DLP printer (3D SLA printer) 
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