So, I've wanted a 3D printer for as long as I knew of their existance. I saw the prices for a good printer and I decided the only way to own one was tyo build one. So, the past week has been designing and planning for the printer and yesterday I got to building the base.
This printer will use light from a projector to cure light-sensitive resin called MakerJuice. It will be held in a very small fish tank, maybe 1 or 2.5 gallons, and the printed object will be pulled out via coarse plate pulled up by a stepper motor. Here's a pic of its early stage:

I ordered an Arduino to drive the stepper motor with and it should come on tuesday! YAY! So I will keep this thread posted and updated during the build process.
Please post with suggestions and maybe about things you think may not work. Help is much appreciated Smile
This is an ambitious project! Are you designing it completely from scratch? Have you verified that the projector will have high enough intensity to cure the resin?
elfprince13 wrote:
This is an ambitious project! Are you designing it completely from scratch? Have you verified that the projector will have high enough intensity to cure the resin?

What do you mean by "from scratch?" We have not made sure that the projector will cure the resin but just in case it doesn't there are ultraviolet light bulbs that we (my dad and I) can replace the current bulb with. It is wavelength that cures it and not intensity.
All the stuff here was in our garage except the projector. Is that what you mean by "from scratch?"
By "from scratch" I meant are the plans of your own design, or were you working from pre-published plans? It sounded like the former, but I wasn't sure since there are some open-sourced printer plans.

Okay - I wasn't sure what the curing mechanism was. If you're using an incandescent bulb, which it looks like is the case, you can figure out ahead of time how well it will work with a bit of math. Are you familiar with the concepts of Planck's law and emissivity?
The plans were my idea. I thought of them one day while I had nothing to do. They somewhat resemble what you see in the picture.

I am not farmiliar with those things. Could you explain maybe?
The projector we got was for a large auditorium so it is pretty bright but I don't know if there is any UV light coming out of it. I guess we'll see! Smile
Botboy3000 wrote:
The plans were my idea. I thought of them one day while I had nothing to do. They somewhat resemble what you see in the picture.

That's really cool! I hope you share them in more detail as the project progresses!

Botboy3000 wrote:

I am not farmiliar with those things. Could you explain maybe?

Sure! Planck's Law defines a curve based on temperature and wavelength (or frequency, with a little fiddling) defining the radiant flux of an idealized "black body" at that temperature and wavelength. For a given temperature you get a fixed spectrum that defines the notion of "color temperature".
Emissivity is a measure of how much real-world materials differ from this idealization. This can vary according to all sorts of things, but can usually be decently approximated for given conditions, and for your needs you probably only need a rough approximation.

In theory, all you need to do is integrate the product of the emissivity and Planck's Law over the wavelength interval you care about*. You can do some Googling about lightbulb physics, but I'd guess you can estimate the emissivity to be in the neighborhood of 0.4 here, and Planck's law is:

That means the main trick is approximating (a) the wavelength interval you care about (material specs might help), and (b) the filament temperature of your bulb (Google might help).


Of course you can also do this experimentally, but learning more physics is never a bad thing, and it might be fun to see if your back-of-the-envelope calculations match up with your experimental results.


* Of course none of this applies if you're using an LED or a fluorescent bulb, because they emit light by a different mechanism.
Wow! That's awesome. I'll ask my dad about it. Everything I know about physics is from him. I'll see what we come up with! Smile as for now though, I'd have to wait till I can look at the projector to see exactly what it is and Google the specs about its bulb.
I completely agree. learning more physics is never a bad thing. Razz I would love to learn this and maybe use it for more than this printer. (Today I was so excited because we were learning about strike-slip plate boundaries and earthquakes and I got to explain that it's partially caused by static friction turning into dynamic friction. It was a little nerdy but that's ok Wink )
Have fun! Let me know if you have any other questions about the relevant physics! I can explain a little bit about fluorescent and LED physics as well if it turns out to be relevant, but they're quite a bit more complicated.
No, That's ok. (Unless this does have that kind of bulb) When I get home I will probably program my new arduino (if it came yet) to drive a stepper motor and then Hopefully make the thing that pulls out the model or find a way to have my computer tell the arduino when to move the motor and how far. Thanks for all your help! Smile
Ugh!! Ok, The arduino didn't come today. I can't really move forward with this project until it does. I will make a post when it comes. (probably tomorrow but maybe not.)
Keep suggesting suggestions and comments are always appreciated Smile
Yay! The arduino came today! I just unboxed it:

I hope to get to programming it today! Anyone with any tips on programming an arduino please give me a post. I will be using C++ to program it.
Oh cool; is that an Uno? Arduino programming is pretty nicely laid out; it is mostly just learning the different functions available and what they do. As long as you have a little experience with C/C++, it isn't too difficult to get started. Good luck! Smile
Thanks! I learned a little C++ but I don't think I know enough yet to do this without help from my friend. If you know of any example code or if you have tips about C++ please let me know! Smile
Botboy, the easiest thing to do is just install the Arduino IDE and start programming it in the Wiring language (ie, C++ with the Arduino Wiring library). There are many great libraries already available for things like sensors, communication, stepper motor control, and so on that you can leverage to make your development faster. This is a really exciting-looking project, and I can't wait to see your progress. Have you done any experiments yet with how thin or thick your layers can be, or is that something you will need to do after you get the proper bulb for your projector?
We won't be able to know how thick the layers will be until we know if our bulb can cure the makerjuice. (or until we get a bulb that can and not until we actually get some makerjuice)
I got the arduino IDE and it is very fun! Easy to use which is nice.
Just today we got our stepper motor going back and forth (because of how they work) and we will hopefully get it to drive later today.
My dad says I should make my own circuit and program that drives a stepper motor before I jump to a pre-made library. It's fun though! Thanks for your guys' support! Smile

EDIT: After many many many hours of trying to make a circuit we both agreed to go and buy an arduino stepper motor driver. My dad, however, thought it was "cheating." I just think it's using my resources. Wink
Should come on Wednesday. Then we can start making the moving parts for this project!
I got the stepper driver. It works perfectly. There were some coding problems at first but I worked past them and eventually got it where I can send it a certain amount of "0"s and it will step the motor what many times. I mounted the boards on a peice of wood (temporary) and found something that I can use to plug the stepper driver into a power outlet.
That's all for now! Any suggestions are greatly appreciated! Smile
Botboy3000 wrote:
We won't be able to know how thick the layers will be until we know if our bulb can cure the makerjuice. (or until we get a bulb that can and not until we actually get some makerjuice)
Yeah, that's about what I figured. Thanks for clarifying.

Quote:
EDIT: After many many many hours of trying to make a circuit we both agreed to go and buy an arduino stepper motor driver. My dad, however, thought it was "cheating." I just think it's using my resources. Wink
It's certainly silly to re-invent the wheel if you know how to make the wheel. For the sake of this project, I think it makes sense to use what's out there, but if you want to truly learn, I hope you'll go back and try again at some point.

Botboy3000 wrote:
I got the stepper driver. It works perfectly. There were some coding problems at first but I worked past them and eventually got it where I can send it a certain amount of "0"s and it will step the motor what many times. I mounted the boards on a piece of wood (temporarily) and found something that I can use to plug the stepper driver into a power outlet.
That's all for now! Any suggestions are greatly appreciated! Smile
That's great work; keep it up! I'd suggest only that you take a look through the stepper driver circuit and see if you can figure out how it works, as per my comments above.
Ah, that's a nice idea. I might try to figure out how the driver works but a lot of the board is inside a big black box.
Your "re-inventing the wheel" idea is exactly what I thought. My dad, having seen it work, is very glad that we bought one now, and the price we bought it for we couldn't have beat even with Digikey.com.
I will try to work on it more this weekend, despite the fact that we don't have four stepper motors. This weekend will probably be mostly figuring out how to sync up the video (that will play on the projector to print something out) and the stepping signal. If anyone knows how to sync a USB signal with a video, please give me a reference to a website or something that explains it (I don't just want the answer, I want to work for it Wink and as Kerm said "Nothing's fun without a bit of a challenge.")
After a lot of time spent not working on the 3D printer but instead learning Blender and trying to learn ASM, my dad and I have come up with a revolutionary idea (that after some research someone had already come up with) that would make the printer smaller while maintaining the current printing envelope. Instead of a modified projector doing the UV projection, we will use a modified monitor!!!

We researched makerjuice and found that its peak curing wavelength is 365 nm. We will replace the backlight in the monitor with either a UV bulb or a few (10 - 20) UV LEDs that put out 365 nm light. That's where we are right now with this. We obtained a monitor for $5 and it works. We will be trying to find a source of UV LEDs that aren't awfully expensive. I'll keep posting as things keep happening. Smile

Added bonus: Now we have a projector to play with! Razz
Are the black pixels in the monitor dark enough to block the light of the UV LEDs? I wouldn't be confident that the dark areas would be enough to prevent your liquid resin from curing until you test it. If it does work, is there a threshold at which it stops working? Is there any value to using gray pixels to semi-cure parts of the resin?
  
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