Build Your Own SLA/SLS

Hello everybody,
Let me start by thanking Steve for putting together such a wonderful piece of software.
I want to share my handiwork with all of you. Initially my only intention was to build a machine completely from scratch, you know, buying the steppers, gears, aluminum extrusion, etc.. but then I came up with a better idea.
I work in electronics and computers recycling and it's amazing the amount and variety of stuff that goes through my hands. I knew that eventually would get together all the parts I needed with as little expense as possible.
A couple of months ago I had been experimenting with a CNC mill and I had some leftovers that I have been able to use as well.
So, here's my list of components and the places I have gotten them from:

• First, the Z axis. This one I bought already made on eBay, I paid 249.00 bucks with free shipping. I don't know much about it but looks pretty solid and seems to have enough torque.
• The wooden box was obtained from a discarded sub-woofer enclosure. It has plenty of room for a projector. All the cabling and controllers will be placed inside for a more professional look. To prevent skewing, or tilting of the z-axis, it is reinforced with recycled aluminum plates on the bottom.
• The acrylic frame that will surround the vat was found inside a discarded LCD monitor, it is 3/8" thick and it is very strong, too bad it is not transparent so it could be used to build the vat as well.
• The build platform is made of black anodized aluminum and was the heat sink for an old computer processor
• The stepper driver was a leftover from the CNC project I mentioned above, I have another left and I'm planning on using it for the tilt mechanism.
• The piece of fused glass I bought on eBay, the seller took a bit longer than I expected to ship, but to compensate, he sent me another piece along with the most transparent pieces of glass I have ever seen. I'll probably have those etched with laser with a logo or something and place them on the finished machine.
• The arduino was bought on eBat also, it is loaded with GRBL.
• The power supply for the stepper driver came form a discarded printer.

As you can see, my expenses so far have been around 300.00. I know this means nothing if the machine turns out not to be functional, but I am taking all the possible steps to make this machine something I am really proud of.

Here's the top view.

Arduino and stepper driver.

Build platform and fused quartz plate

The Z-Axis

Wow, it's looking great! So, what's left for you to do? It looks like you're going to need a VAT with a coating. Also, a tilt mechanism or some method for releasing the model.

I still need to build a vat, which will have a tilt mechanism actuated by a stepper with an eccentric. I am still trying to decide on the coating, I know encapsulating silicone is a good option but tends to burn and lose transparency over time. PTFE is another option, combined with the tilt mechanism releasing the model will hopefully be easy. I don't want to destroy the fused quartz plate. I will be posting pictures of the vat, along with the tilt mechanism soon.

Also I need to set up the build platform, and of course the projector. I've been considering a few options besides the DLP projector, I have plenty of LCD monitors to play with and probably apply the Opaque Projector principle. Also I found a very interesting article you may want to take a look at here: http://www.das-labor.org/wiki/LaserExposer , which could be easily applied to an SLA and uses polygon mirrors instead of galvos. I am trying to reverse engineer a laser printer (which I also have aplenty) for this purpose. I think resolution would be greatly improved.

Take care,

Al

Great work so far!

"As the lenses in the polygon mirror assembly had the wrong optical properties for my application (different wavelength and different focussing distance), I removed them all. The optical system now consists only of the laser, its focussing lens, and the polygon mirror. There is one problem with this: as the beam length varies with the angle of the deflected laser beam, the focus of the laser lens would also have to be adjusted for each beam length. As this isn't done, the laser gets blurry at the ends and the middle of the scanline. But this is not a problem in practice, as the image gets sharp enough."

Good for exposing PCBs, but it would be lacking for SLA without those lenses. However, I'll bet one could transmit longer wavelengths, say around 400 nm or more.

I agree entirely. Besides, the laser is too close to the PCB. Without the lenses the laser would be constantly going in and out of focus if the assembly is too close to the bottom of the VAT, but with the right combination of laser and resin this process would work wonderfully with amazing x-y resolution even with the lenses left in the assembly. This distance should be as approximate as possible to the distance between the laser and the drum in the original configuration of the printer.

Almost there.
I've been incredibly busy and haven't been able to work much on my 3D printer.
I am almost done with the tray, which will have a passive tilt system suggested by some members of the forum. The bottom of the tray will be fused quartz with FPE release (with adhesive on one side) I don't want to place it in the tray until it is almost done since I have a terrible case of butter fingers and don't want to break it. I believe that if the Z stage has to strain a lot in order to release the part from the tray it is time to rethink everything.
For now, I will start with a Dell 3400MP, I will deconstruct it as needed to achieve right focal distance, and maximum UV generation.