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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>Can you attach a photo of the fan? Thanks.</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>Will any projector work for this? I have a mini projector i purchased from Brookstone a while back and the image is pretty clear, especially up close </p>
<p>Is there anyone still checking in on this Instructable that built a printer based on this design? If so, I'd like to ask you how you dealt with a few of the problems that people encountered doing the build.</p><p>Thanks in advance for your help.</p><p>Mike</p>
<p>Thank you Mastermind!!!! I finally made it! </p><p>I did not remove UV filter. Added +2 macrolens</p><p>Makerjuice SF resin cures in 4 sec per layer. </p><p>Makerjuice WaxCast resin cures in 20 min per layer.</p><p>Improvement 1:</p><p>I deepened 4 neodim magnets into MDF case and acrylic cover.</p><p>Improvement 2:</p><p>Aluminium base appeared to be too thick and heavy. So I </p><p>counterbalanced it.</p><p>Makerjuice SF resin</p>
<p>Hey, excellent looking build George. Just got one running myself, same projector but went with nanoDLP on a raspberrypi3 and sparkfun easy driver in lieu of the arduino and stepstick. </p><p>Just want to ask...did you mean 20 seconds per layer? or really 20 mins per layer? That would make for some terribly long builds...but it could make sense with the UV blocking filter still in. My layers are curing in ~4 seconds with white maker juice G+ </p><p>I have some maker juice wax cast in the mail, excited to try some investment casting wax as well!</p>
Makerjuice SF - 4sec. Makerjuice Waxcast -20min.
<p>Hello Mastermind and everybody!</p><p>I tried to connect endstop/limit switch to arduino UNO. I connected it in NC mode to 11 pin and GRND pin</p><p>So, it works but printer &quot;hangs&quot; after $H command. It finds limit switch and then do not respond. </p><p>To enable Limit stop switch I sent that commands to GRBL:</p><p>$20=1 (soft limits, bool)</p><p>$22=1 (homing cycle, bool)</p><p>I tried hundreds of different iterations (NC, NO mode, $23=1, $5=1 and so on) and can not solve this problem.</p><p>There is some note In GRBL website: </p><p>&quot;NOTE: Check out config.h for more homing options for advanced users.&quot;</p><p>I<br> didn't find where can I check config.h. I tried to open <br>grbl_v0_9i_atmega328p_16mhz_115200_for_SO2.hex in arduino app, but it do<br> not open this file. How can I check abd modify this firmware?</p>
<p>Sorry, I wrote wrong. </p><p>I connected limit switch in NO mode to 11 pin and GRND pin</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>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>Did the 10W UV led work for you? I have a 10W UV too and was wondering if it was worth the effort of not, thanks.</p>
<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>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>Hello! </p><p>I tried two dvd-roms. In GRBL or CW motor does not move. I tried to revese motor's 4-pin connection. </p><p>Firmware uploaded successfully &quot;28690s<br>byte uploaded&quot; </p><p>When motor is not connected to driver: pin voltage 1 | 4.13v | 2 | 3 | 4.13v | 4</p><p>When motor is connected to driver: pin voltage 1 | 0.32v | 2 | 3 | 0.32v | 4</p><p>UNO connected to COM31 (CH340)</p><p>UNO was bought here:</p><p><a href="https://www.aliexpress.com/item/UNO-R3-MEGA328P-CH340-CH340G-for-Arduino-UNO-R3-USB-CABLE/32581591378.html?spm=2114.13010608.0.0.7Aozdr" rel="nofollow">https://www.aliexpress.com/item/UNO-R3-MEGA328P-CH...</a></p><p>Driver:</p><p><a href="https://www.aliexpress.com/item/A3967-V4-4-EasyDriver-Stepper-Motor-Driver-Development-Board-for-Arduino/32541605714.html?spm=2114.13010608.0.0.7Aozdr" rel="nofollow">https://www.aliexpress.com/item/A3967-V4-4-EasyDri...</a></p><p>Maybe I need to plug in additional power to Arduino? How much power it needs? 3v or 5v?</p><p>How else can I test what is wrong?</p><p>PS: I've read all of the comments.</p><br>
<p>OK! I tried to do like in that comment and it MOVES!!!</p><p><br> <a href="https://www.instructables.com/member/mdecicco" rel="nofollow">mdecicco</a><br> <br> <br> <br> <br> <a href="https://www.instructables.com/member/ScottG12" rel="nofollow">ScottG12</a><br> <br> <br> <br></p><p><br> 2 years ago<br> </p><p>I had the same issue at first. <br>Try moving from the Vin to the +5v on the Arduino. I had to do this for <br>it to work for me. I also moved everything to the 28690 as he quoted.</p>
<p>will you make a insturtable with the upgrades as listed at the end or has this one been updated</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>it will not work with this design.</p><p>1. The resin is special daylight version, as the light from a phone disply is to low.</p><p>2. The design uses the display under, insted of top. As the light from the display isn't directed like in a projector. You need the light close to the resin, so it doesn't spread out to much.</p>
<p>I have a question, I'm builidng a larger scale printer, and I have put enough money into it that i want to stay away from ramps, and or arduino interfacing, is there a way I can run my motors from my computer directly(well run my driver boards from my computer directly)?</p>
<p>why would you want to drive the printer from your computer without an Arduino?</p><p>It is all about software, so you could. But the Arduino gives better control, and the bugs in the G code interpreter and drivers are all fixed in the GRBL software.</p><p>Look at it as a device. You dont drive the stepper motors in your printer directly, do you? And using your computer, you could easily end up in timing problems...</p>
<p>Very interesting! I have a regular 3D printer, but saw this and thought maybe I should give this a go.</p><p>I do have a question. It's not clear to me what determines the build size beyond the platform which is being submerged. Given you are using a projector, you should be able to change the focal length and set the projector further away giving you a larger exposure area? This might still give you a small foot print for exposure, though.</p>
<p>If I'm not wrong DLP printers have a small build size because of the intensity of UV light required to harden the plastic. </p>
<p>i have a problem, how is the conection betewen CWS with arduino, i used gbrl, using xloader, and then i dont have an idea whats next, greetings</p>
<p>Step 9: Electronics - OK, I'm completely lost. I have a breadboard, but it's not clear to me how I plug the items together, whether on the bottom side of the breadboard I need to make solder connections, how the shield, breadboard, and UNO board correctly connect to one another. I'm guessing I'm going to have to try to hire a local electronics person to help me. This seem like the best course for me? Thanks.</p>
<p>What exactly do you have? He made a custom board to fit everything together. You dont need to do it exactly that way. If you want, message me and I will walk you through how to set everything up with what you have. ~TruFord</p>
<p>Hey, it's been ages since you offered this help, but I have a question about this step.</p><p>I etched a board based off of matstermind's Eagle files, but I subsequently realized it's intended to be double sided?<br><br>Can I simply connect all the grounds to a ground plane and hook that to the ground pin of the UNO?</p>

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Bio: I am a 23-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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