Build Your Own SLA/SLS

I started a new topic to document this vat design. Regardless of success or failure, I think that there is some value in documenting it since others are also seeking the same goal. The goal being transparent, consistent, reliable, and durable vat bottom release surface.

While playing around and probably reinventing the wheel, I sort of glued some glass to the aluminum build plate with resin. There was no coating on either piece since I was testing the surface of the build plate see if the cured resin would stick to it reliably. .25" thick glass is almost impossible to remove intact and the resin stayed on the aluminum plate. This glass shelf material has been handy for a variety of things while building. Next I tried .12" window glass while it was more flexible, it was still too stiff. I tried gluing .12" glass to the build plate with resin again and it came off a lot easier but I was afraid that the glass would break. If not this time, then at some point in the future. It was enough of an improvement that I started a brief search for a material that would function in a similar fashion. I know that some are using thin, self adhesive, teflon fastened to the glass. Others are using what amounts to a teflon diaphragm. It sounds like there are some UV degradation issues but they are working to one degree or another.

The vat that I am building has a 12" x 12" x .031" piece of Gorilla Glass as the floor of the vat. It is attached to the frame on 2 sides using silicone. The other 2 sides are free to flex up to .5" . An "L" section of silicone material provides a flexible end wall to the vat and allows flex in one direction. A piece of .12" thick glass is mounted under the Gorilla Glass for support. When the build plate lifts, the Gorilla Glass will be able to lift off the glass support, flex, and peal away from the cured resin. I did one test before starting construction. It was similar to the tests above, only a much larger area. I did not take a careful measurement, but estimate that it was a 6" x 3.5" oval compared to the previous tests where the resin was no larger than a 2" diameter circle. Lifting the Gorilla Glass by two edges, it flexed and pealed off easily. No coating was used, just bare glass. The advantage that I see if this works is that the glass will remain free of wrinkles, tears, and UV damage. It is also as clear as, well, glass... ;^) It will be interesting to see if there are issues with refraction.

I also hope that this will eliminate the requirement for any tilt or slide motion. The test prints will start with only a Z axis lift and go from there.

Addition on Sunday eve.
I did two prints using a glass build plate since I didn't have time to fab another aluminum one. Both prints released from the build plate before finishing but the first one was almost done and turned out OK for a test. The print is 5.12" x 3.5" x .12". The print released from the vat fairly well at the beginning of the prints and seemed to be bonded more later in the print. The first 15 layers are solid and then the relief image is the last 15. The part has warped about .09" in 3 hours. On the first print the lift was 6mm and it was not enough to get consistant release without a little manual pressure on the vat glass. On the second print, the lift was 12mm and it was releasing from the vat on its own but popped off the build plate a bit more than half way through. The resin is MakerJuice SubG+ yellow, original pigment.

I need to try an aluminum build plate again before thinking about using a coating. I am still optimistic about being able to get a good release without coatings.

Hi,

that sounds pretty promising, i was thinking of using FEP film for this, the thickes FEP film i can find until now is 0.3mm, it might have the same effect.

i have 0.05mm and 0.1mm on order.. maybe i also need to order 0.3mm fep film just to test it.


/**EDIT**/
just found that cshyde is selling 0.5mm thick fep film.. a little to pricey for me though

Thanks for starting this thread, and keeping us informed of your progress, I am following your work.

I had a successful print tonight if you don't count snapping it in half while taking it off the build plate. A little UV laser and it was good as new. I had been having trouble with prints not staying attached to the build plate and then realized that I had switched resin to SubG which has a shrinkage of about 9%. SubG+ was used for this print and it has shrinkage closer to 3%. It was a little over exposed but turned out OK.

The print was made directly on the Gorilla Glass with no coatings.

The long side of the print was oriented 5 degrees off of the Y axis to help with pealing. The lift move was Z2F20,Z4F30,Z2F100 and then down at F200. There was a little popping/crackling noise but not very loud. Previously the lifts had been a little faster and that may have caused some of the premature release from the build plate. I had tried one using supports in SubG resin and it failed. This time with SubG+ I added a brim and printed directly on the build plate.

This is a promising start and I will be working with progressively larger prints. The build plate is 10.5" square and I am printing at 1 pixel = .01" at this time.

As another option I bought an iPad replacement screen from China for $20. eBay purchase. It is not Gorilla Glass but a similar product. The touch screen sensor is bonded to the screen with silicone and it is not inclined to peal without breaking. If you are over confidant and try hard enough you will find that not only is the sensor coming of in pieces but the screen is also broken.

The failure mode on the glass is interesting because the cracks run but don't shatter. At any rate there is another on the way and I will try a slow approach to pealing the sensor off, and only after doing some other testing to verify that it has to be removed.

Where do you get gorilla glass? I think an Ipad screen has it, but I don't think I want to rip off the screen and the sensor.

Someone asked how I work with nonstick Gorilla Glass. It is not so much that the glass is nonstick as much as it is very flexible. I would like to be able to use it without a coating but the jury is still out. My tests to date have been without any coatings but have yielded mixed results. The GG behaves like a passive tilt mechanism. If Sylgard was applied I think that it would do really well but my goal is to print without a coating so that has been the way that I'v been running prints. Not much progress since Christmas but hope to be back on it soon.

For most aspects of vat building the GG is the same as plate glass except that if the vat is large another piece of glass under it is required for support. It also needs provision for flex along one axis. I used the silicone strips that are sold at Walmart in the kitchen gadgets to form the ends of the vat. The strips are marketed to seal the gap between the counter and range top.

Just wondering how the Gorilla Glass is working for you? I'm about ready to order some and try it.

Sorry, I have been tied up and away from this for a while. Have not been working on it lately.