A Solar-Powered 3D Printer Prints Glass From Sand 139
Tx-0 writes in with a story in Colossal Art & Design. From the article: "Industrial designer and tinkerer Markus Kayser spent the better part of a year building and experimenting with two fantastic devices that harness the sun's power in some of the world's harshest climates. The first he calls a Sun Cutter, a low-tech light cutter that uses a large ball lens to focus the sun's rays onto a surface that's moved by a cam-guided system. ... Next, Kayser began to examine the process of 3D printing. Merging two of the deserts most abundant resources, nearly unlimited quantities of sand and sun, he created the Solar Sinter, a device that melts sand to create 3D objects out of glass."
OK, read TFA and watch TFV (Score:3, Informative)
It's sintering, and it looks like you end up with lots of little pits and stuff in the finished work. It's also probably a glass-sand aggregate of sorts. They didn't show close-ups of the objects, or any attempt to "finish" them. They might be strong when finished, but not clear.
Re:Annealing? (Score:5, Informative)
I've got a passing interest in glasswork, and one of the things I learned is that it's more complicated than "melt into mold, let it cool". Glass has to go through a carefully controlled cool-down period so that the molecular structure will set up properly. Otherwise, the resulting object is far more brittle than it should be. If not done properly you can have cracks form during the cooling phase, ruining the object.
Does the incremental deposition solve the annealing problem? Being able to make glass objects without having to carefully control the cool-down would be very nice.
I was a glassblower and glass bead artist for a while. Careful cooling is pretty essential for lime glass, which is what we mostly use. It's less important for borosilicates like Pyrex, which is why glass casserole dishes can survive being put onto 200C metal racks in the oven, and it's even less important for fused quartz that's straight silicon dioxide. You can stick a pyrex rod that's less than a centimeter in diameter straight into an oxypropane flame without it splitting or snapping, and I believe you can do the same with a 3 or 4 cm quartz rod. Obviously this stuff isn't pure silicon dioxide, but it's closer to SiO2 than it is to lime glass.
Incremental deposition probably won't solve the annealing problem, but it'll change it: instead of having strain across big areas, you'll have little bits of strain distributed between each layer of glass that's put on so you're liable to get a lot of small cracks through the porous material, rather than one big catastrophic crack. However, all those little cracks generally tend to grow, but that may be somewhat helped by it being an amorphous, impure material: it's harder for cracks to run in long straight lines in crappy heterogenous stuff.
Skip the commercial blog... (Score:5, Informative)
Original source is here: http://www.markuskayser.com/work/solarsinter/ [markuskayser.com]