I have been on a hunt for the past several years to find a cheap and simple, yet moderately high resolution 3D printer. I had 3 different 3D printers partially constructed when I heard about the amazing technology of DLP Stereo lithography (SLA) printers. I have finally found enough parts at the right price to construct a fully functional printer capable of amazing quality with spending less than $100. Top down DLP printers in their simplest form have only one axis of motion, a video projector, and minimal electronics. They do not require a heated or perfectly level bed, there is never a clogged or wrong temperature in the extruder as it does not use an extruder. And the resin used has a comparable price to FDM printers.

I Started this project to show that you don't need a lot of money or special equipment to start experimenting with 3D Printing. While this printer was not meant to give the same quality as an expensive printer such as the form 1, the results I got exceeded my expectations. There are still a few bugs to work out but, it definitely is usable. If you would like to see a video of it printing, the video is in Step 12.

The chimera (ky-meer-a) is a mythological creature that is made up of 3 different animals, this printer is made using the recycled/modified parts of 3 different categories (projector, toys, and old computer stuff), hence the name.

I am always looking for constructive criticism, let me know of any ways I can improve on the project, or the instructable!

Before continuing I would like to apologize for the not-up-to-current-standards pictures and video quality, I am working with almost or over a decade old equipment in bad lighting. I will try to update the photos once I get a better quality camera and/or find a better location for pictures.

Update 7/14/15 This project won one of the enthusiast grand prizes in the 2015 3D printing contest. Thank you everyone for their votes, and thank you instructables for continuing to be the best online DIY community! I am glad I could contribute to this site and hope my next project will spark as much interest as this one did.

Step 1: What is a dlp printer?

Let’s start out with the basics, in 1986 Charles W. Hull created stereo-lithography as a form of fabrication that uses ultraviolet light to cure a polymer resin to create solid objects. Since then, projection technology has opened up a highly accurate, fairly cheap, and easily accessible form of ultraviolet emission. A DLP printer is different from the "normal" FDM (fused deposition molding) 3d printers that have been dominating the community, an FDM machine uses an extrusion system similar to an advanced hot glue gun that is attached to an apparatus that can move the extruder in an X, Y, and Z direction. The extruder must follow a path made by a computer to print objects. A DLP printer uses the stationary projector to display the entire X and Y portions at once onto a resin that turn from a solid into a liquid from the light emitted by the projector in the shape of the projected image, and uses one axis for the Z motion.

Top Down vs. bottom up

  • Resin tank vs. resin vat - The biggest difference in the abilities of top down vs. bottom up printing comes from the limits of the container that holds the resin. In a top down system the platform and object slowly gets submerged deeper into the resin and is limited by how deep the tank is. This is not a problem if you only want to make small detailed prints as I designed this printer to do. Bottom up printers use a shallow tank and the object rises up out of the resin and is not limited by the vat size.
  • Viscosity - Top down system require a low viscosity resin in order to work properly, as it relies on the resin to flow on its own over the platform, and level properly when the object is lifted to skim just below the surface. Without a wiper apparatus you have to wait for resin to settle before you are able to print with your desired layer thickness. Luckily, MakerJuice's SubG+ has a low viscosity and works very well for top down systems. Bottom up printers squish the resin to the desired layer thickness.
  • Warping - Warping effects both types of printers, but effects each printer differently. In a bottom up printer, each layer of the object is created pressed between the bottom of the vat and the previous layers, that combined with the ability to use low viscosity liquids provides very little warping per layer. However with top down systems the object is free to curl and warp if it does not stick properly to the build platform. And low viscosity resins tend to have a slightly higher shrinkage per volume unit.
  • Object stress - Bottom up printed objects suffer from numerous forces acting on it throughout the build process. Every layer has a suction force trying to pull the object off of the build platform, and tilt/slide mechanisms are applying forces in many directions at once, along with gravity pulling down on the entire object. In a top down printer, the printed object has almost the same density as the liquid resin so gravity it not a problem. And the only forces acting upon the object is shrinkage.
  • The ultimate advantage to top down over bottom up is its simplicity, where bottom up printers require tilt/slide mechanisms and expensive/messy vat coatings, top down printers only move up and down and can use almost any container for the tank.

Even though bottom up printers are capable of printing larger and higher quality objects with less resin, I decided to build a Top down printer for its simplicity and ease of construction.


<p>Thanks Mastermind, need some more calibration.. but, it's working!</p>
About the projector, I've ended up switching the uv filter by a regular glass, the first fitted by size but snapped to two pieces because of the hit, the second glass i had didn't fit exactly, it left 2 mm of space, right now I'm working with the &quot;low lamp mode&quot; at the projector manu. I got the calibration cubes at 8 sec exposure, and 14 sec at the bottom. <br>Next thing I'm about to do when I'll have the time, is to buy a tempered glass, hopefully it won't snap with the &quot;high lamp mode&quot;
<p>The problem is temperature, so leave the glass out (remove the UV glass, don't replace the UV glass with anything) and add an extra fan where the thermostat for your projector is or at the <strong>light tunnel </strong>(<a href="http://g01.a.alicdn.com/kf/HTB1xakRLVXXXXaRXFXXq6xXFXXXN/-font-b-Projector-b-font-Light-Tunnel-Light-pipe-for-font-b-Optoma-b-font.jpg" style="">http://g01.a.alicdn.com/kf/HTB1xakRLVXXXXaRXFXXq6x...</a>). I added a fan to cool down the light tunnel, my fist projector burned due to the plastic melting around the light channel (after about 4 hours). If your projector has a sensor for the glass, short the sensor.</p><p>Also, play with the <strong>contrast </strong>and brightness, read up on how DLP chips work, if you max the brightness you might cure the resin around the part.</p><p>I hope this helps :)</p>
<p>So adding a piece of glass stopped your projector from shutting itself off? </p>
Replacing*, and yup.. It's working, but with the low lamp mode, which is good enough if your lamp is new (and probably Chinese)
<p>I tried the same thing and the machine would shut down shortly after. So if I switch to low lamp mode it will prevent the shutdown? Did you try low lamp mode with no glass at all? Where did you find the 1&quot;X1&quot; glass? I cut mine from a sheet of cheap picture from glass and was worried it may shatter under the heat. My piece of glass was also 50% too thin but I don't know if that is an issue. I was at 60/75 for exposure with the UV filter in and my cube still wasn't complete. I bought the $30 remote and turned up the brightness and tried a 30/45 last night and I was somewhat of an improvement. I don't know what the issue is and it's at times frustrating haha Thanks in advance for your help</p>
I'm using a 4 mm glass, (the uv filter is 3 mm), the glazier (the guy who cut glasses :) ) cutted it for me. As i wrote, the first glass shuttered to two pieces, the second didn't fit exactly and left 2 mm of space from one side so air could flow through.<br>I tried to use the low lamp mode without the filter but after a minut it shut down.
<p>Thanks for your reply. So the objects you printed were from the 2nd piece with 2mm of space? Were both pieces the same type and thickness of glass?</p><p>I tried the one I cut in low lamp mode and it also had some space left on the sides. It worked for about 5-10 minutes then it cracked in half and shutdown a couple minutes later. I just had it on and running to see if it would crack so I wouldn't waste any printing material.</p><p>It would be awesome if someone found out how to bypass the failsafe shutdown. Save us a lot of time and effort haha. I'm going to look up glass cutters here and see if they can do it. Also my UV filter is only measuring at 2.4 or 2.5 mm, it's weird that yours is thicker. I just want to be able to print haha It seems I've hit every bump in the road that you could hit (some were my fault). Thanks for your help!</p>
<p>same glass. 4 mm thickness , that's what the glazier had.</p><p>the thickness different might be because it looks like my lamp isn't genuine, it's probably a chinese replacement.. </p><p>i was wondering maybe a phone tempered screen protector glass would work.. though it's realy thin</p>
<p>I was thinking acrylic but I'm almost sure it will melt inside. I'd love to know the max temperature the filter area gets to be. I'm going to try to get a hold of a glass guy. And good idea, you can get iPhone and iPad replacement digitizers which may work. I actually have a replacement one here that I don't necessarily need to use. I wonder how heat resistant it is.</p>
<p>Nice work! I really like that lightbox idea. what resin are you using? I had thought that clear resin would have too much &quot;bleeding&quot; but it looks like you have well defined results.</p>
nice economic printer design, just for fun I've buy a projector and build 1 printer similar to yours! thx for give me the starting point
What model projector is that?
<p>looks great!</p>
<p>Nice work! your Eiffel tower turned out much better than mine, what resin are you using?</p>
<p>FTD black</p>
Yey! Just finished my first print. To those who started and got disillusioned with bits on working, my 2 cents. 1) I got the upload error repeatably, changed arduino and it worked a charm. 2) stepper motor just wouldn't step, changed DVD drive and it worked like a charm. The instructions for this ible are perfect so if you've done everything to the letter try changing equipment. Just need to do a little more calibration but well chuffed, I've built a 3d printer! Crazy.
<p>Thank you for the Update, I wonder if one could use an old PC Motherboard instead of an Arduino? or something like Raspberry Pi? My Ultimate goal would be to one day have a large scale High Resolution 3D printer alongside a PVD Metalizing machine, but for now I would be really glad if I could compliment your 3d printer design with my DIY Spray On Chrome(Spray On Silver really) system.. Thanks</p>
<p>Thanks for the feedback! and for sharing your build!</p>
<p>Thank you, matstermind, for the awesome project! I got the printer to work quite well! My first print of the batman bust in the pics, as well as subsequent prints where I was playing with the settings.</p><p>I followed the instructions as closely as I could, even getting the same projector and finding (by sheer luck) the same DVD drive assembly shown in the instructions. My printer does differ in the following ways though:</p><p>1. I could not remove the UV filter or the projector would failsafe and shut down. As a result, I had to up my exposure times to 30s and 45s (normal and bottom layers respectively). It seems obscenely long, but seems to work so far..</p><p>2. I had the hardest time getting the models to &quot;stick&quot; to the aluminum platform, as it would pool a few mm's worth of resin on top prior to the printing. To allow the resin to drain a bit, I drilled a series of holes in the platform and also sanded it down a bit.</p><p>I'm still having a hard time printing a model of the Eiffel Tower, and suspect it's either because the model has too much detail at the size I'm printing and/or my exposure settings are off. But, at least I have a great starting point!</p>
<p>I love it, have to build this!</p>
<p>Excellent work! I had to double the exposure settings for my machine to print the Eiffel tower because the layer points are so small, and it still didn't turn out all that great. I used a needle to scratch the surface to get my prints to stick, and have been meaning to drill holes. I'm glad to see you got it working!</p>
<p>looks like a nice little printer, but i don't think SLA is something for me, the material is way too expensive.</p>
<p>hi,</p><p>you say &quot;from a solid into a liquid&quot;, I think you mean &quot;from a liquid into a solid&quot;</p>
<p>I'm curious if I could implement a smartphone instead of a projector? I've seen a resin printer that uses a smartphone but will it work with this design?</p>
<p>After a few months of respite finally finished off my build, went from misshaped cubes to nice skulls. The shutter really helped as even black pixels slowly cured the FTD resin, salt water working well too. Still need to re-calibrate it though. Very nice guide!</p>
<p>How did you fix the misshapen cube issue? I abandoned the project a long while ago because I couldn't figure out what was going wrong.</p>
<p>Hey first of all your setup looks great! Im working on my machine, and Im struggling with the Iris wiring and control, coudl you elaborate a little on the wiring and Gcode you used for the iris actuation between layers? thank you !</p>
Currently in bits as I just moved, and I'll have to dig out the laptop to look at the Gcode commands. From memory I used the M8 and M9 coolant control codes but as my rotatory solenoid is not sprung I built an single input inverting H-Bridge to flip the rails. Wouldn't recommend it, see if I can help more after I've dug out some bits.
I completely understand, moving with electronics/machinery always sets me back! But thank you for the response!! I actually am using a pico DLP projector that I have installed a 10w UV led in, to reduce the heat I would like to use the shutter control to turn a solenoid controlling the LED on and off. I didn't even think about using coolant off and on commands but that should would pretty good! Will the pin for cool an on/off just provide + voltage when enabled?
<p>Sorry got distracted with thinking (/researching/testing) about using a dslr camera shutter instead of a solenoid and bits of card (turns out the camera shutter I bought is solenoid based anyway). I looked into using a pico projector, seemed more expensive for less resolution, although smaller and simpler. There was a laser based non DLP MEMs one that was tempting (no focusing required). Anyway if it is still useful, the pin just provides on and off, M8 on and M9 off.</p>
<p>I'm having trouble getting the build platform to move. I've gone through the instructions a couple of times but with no results. I know the motor and arduino work. I also have made sure that I am using the correct hex. file. If anyone has any helpful troubleshooting suggestions I would appreciate it!</p>
I took a chance on an experiment...I used a thin layer of wood glue to stick some fiberglass window screen to my build platform. I baked it dry to be sure it was well set. And then I used a &quot;bed of nails&quot; raft under the large flat base of my object. I let the first 5 layers of the bed of nails have a really long exposure...20 seconds is long for my setup. The support nails were 1 mm thick, and 3 mm apart and 5mm tall.<br><br>The nails stuck well and grabbed the screen. When the base started to print on the raft of nails, the raft held tight.<br><br>I did end up with holes in my print. It started about 1/3 of the way into the build. I'm floating subg+ on saline and I think I had too thin of a resin layer on top of the saline, and during the dip phase i think (the print was unattended) some saline bubbles got pulled in. Unfortunately, saline does not tend to cure very well ?. So, a point of note...start with plenty of resin if you are floating it on saline.
One more thing...the window in my door is made from Gila window film $15 for a roll at Advance Auto Parts 2 meters by .6 meters...6.5 ft x 2 ft. If I put a sheet of the film in front of the projector my cure time goes from 4 seconds to over 30 seconds. with the door closed and polarized UV work glasses on, I think my eyes are pretty safe. Also helps keep the atmospheric UV off the print vat.<br><br>
Thanks for this inspiring ible. I built mine larger using a belt drive from an old scanner. i'm using Maker juice g+.<br><br>problem...if I try printing large flat objects...at least at the base, they don't stick. if the object is small, it sticks ok...but still not well. I've tried steel, aluminum and brass all well scratched up with sand paper and hatch cut with a sharp blade.<br><br>I've floated a lot of resin and need help.<br><br>I am new to this. Any thoughts on better build platform materials. I have a really HOT projector. cures .1 mm in 2-3 seconds. full screen 1024x768 projects to 4cm x 5.5 cm.<br><br>I guess I need to learn how to properly calculate cure times, but have not yet found a good reference.<br><br>I hope someone can give some good pointers. do I need to turn down the brightness of my screen and/or projector...longer exposure at lower intensity. Would pre printing a grid on the first couple of layers help...then start in to the real build?<br><br>suggestions of any kind are most welcome.
<p>Hi, the resin is not available, what other resin we can use?</p>
<p>Great project, but the software is not open </p>
<p>Really nice job.</p>
<p>awesome work, thank you for sharing!</p>
<p>Excellent project and great instructions.</p><p>I'm a little confused about the actual resin printing process. How much resin needs to be above the platform? Does only the top surface of the resin harden - maybe the UV doesn't penetrate very far? If that's true, then is it really just a matter of being sure the platform is close enough to the first cured layer so it sticks? </p><p>And do I understand correctly (probably not) that each time a layer is printed the platform submerges to get a little fresh resin, then rises back up except not quite as far as it went down (difference being the layer height)?</p><p>Dumb question: Is top-down printing - looks like the bottom layer gets printed first. </p><p>Thanks, really a great project and explanation. </p>
<p>Is it possible to build chimera by someone who never build anything before? Is it hard?</p>
<p>do you have the blueprints and other documents in a pdf format as I don't have solidworks?</p>
<p>do you recommend any other software besides creation workshop?</p>
Amazing project, and good explanation. Fantastic!<br><br>Congratulations and thanks to share!
<p>Now knowing that the typical smart phone is a lot less bright than a DLP projector... I just saw another instructable on here about using a smartphone as a projector... womder if it might be able to be used in this design to make it even cheaper (lower resolution alternative though)</p>
<p>Awesome project! Congrats for share your project!</p>
<p>Pricing may be out in UK</p><p>I'm really keen on making one of these but eBay prices for used DLP projectors this side of the pond start at about &pound;60 which makes about $100 US. Most are a lot more. New ones tend to be more like &pound;250 to &pound;700, which is getting near $1000. I'll keep looking, but UK prices are not too good, especially now we've voted to leave the EU.</p>
<p>Would the type of photopolymer for stamp works for 3d printing? Any photopolymer works?</p><p>What should it have to be able to use for 3d printing? A specific photopolymer kind?</p>
<p>Thanks for the awesome project! I'm so happy I got to make it, and the instructions were fairly easy to understand even though I know nothing about this stuff. I'm still doing some calibration, any idea why the bottom of all my designs look &quot;smooshed&quot;? My projector is fairly strong, I'm using 8 seconds for exposure and 16 seconds for bottom layer exposure. The bottom is always looking a bit &quot;bigger&quot; than the rest of the design, however (see pics), and I'm not sure why. :/ I've tried changing the bottom exposure time by decreasing it and increasing it, but the size won't change - the bottom layers are still a bit bigger/thicker than the rest of the design. I'll just keep testing other settings for now :)</p>

About This Instructable




Bio: I am a 22-year old engineering graduate who is constantly tinkering, making, and building. I have always enjoyed disassembling old electronics and re-purposing them. I ... More »
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