Vat using Gorilla Glass and no coating
Posted: Sat Dec 28, 2013 10:58 am
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.
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.