3D Printing Glass

For most of us, 3D printing means printing in plastic of some sort — either filament or photo resin. However, we have all wanted to print in other materials — especially more substantial materials. Metal printers exist but they aren’t cheap. However, it is possible to print molds and cast metal parts using them. [Amos Dudley] prints molds. But instead of metal, he casts parts out of glass.

[Amos] covers several techniques. The first is creating a relief (that is a 3D shape that grows out of a base). According to the post, this prevents difficult undercuts. He then casts a mold from silica and uses a kiln to melt glass into the mold. You might expect to do that with a full-size kiln, but you can actually get an inexpensive small kiln that fits in your microwave oven.

The second technique is a lost-wax style process in which the plastic burns away in a high-temperature kiln. The final technique creates an internal void to make it appear an object is inside another object.

For small objects, this looks like it would be very accessible. Art suppliers have inexpensive kits for glass casting for which you only need a kiln or a microwave. Small kilns are reasonably cheap, or you may be able to find someone to give you or rent you kiln time.

The process isn’t much different from casting in metal. We have covered several tutorials.

26 thoughts on “3D Printing Glass

    1. I’d love to see that idea scaled up to the point where a person could print bricks. Or sidewalks. I imagine it would be possible to print bricks with internal voids that would still allow the loose sand to fall out, but have internal supports or spaces to run cables/wires/pipes. At that scale, I wonder if it ends up being more efficient to use solar panels to capture electricity, and use that to power a laser, which does the melting.

    2. Yeah, that’s a good article. I’m thinking somehow add a thermal insulation and storage buffering/equilibriation system and the capabilities of a solar furnace, kiln, and foundry system in certain climates increases significantly.

      https://www.army.mil/article/37355/solar_furnace_could_save_earth

      https://www.criticalpast.com/video/65675027977_solar-furnace_army-quartermaster-corp_heat-generation_officers-watching

      I also wonder why these designs aren’t used more for power plant operations or more commercial/industrial operations?

    3. I assume this is at least one of the options being considered for construction of buildings on the moon and Mars. The question I have is how large the collector would need to be on Mars due to the lower intensity of sunlight.

      1. To get a reasonable lens, good enough for glasses, it will have to be figured and polished by grinding techniques, at least for the moulding techniques being discussed. If you can deal with that, rough grinding a blank will be quicker that casting a blank, as it can be done by the same technique and machinery as the figuring and polishing. and allows the use of glass with better optical constancy than home cast glass blanks. So long as the lens surfaces are section of a sphere, grinding and polishing are within reach of the amateur.

        1. Saul Griffith made a very low cost lens fabricator back in 2001: http://museum.mit.edu/150/16 designed specifically to deal with this. At the time it wasn’t so useful because the bottleneck was getting a good prescription. Now, there are smartphone apps that with a little bit of hardware can do an okay job of dealing with myopia. (I believe they’re not great for astigmatism yet, though.) However, _any_ even vaguely competent job of vision correction is going to be a huge improvement for roughly 2 billion people who need glasses and don’t have them.

  1. This will be the next 3d printed gun fiasco when a meth or crackhead uses this to mould an apparatus. Lol. But more serious note, this isn’t actually 3d printing glass, I hate to be that guy but misleading click bait isn’t hackaday’s style usually, so please dont do it again. Cool project but not in the scope of why I clicked.

    1. A lot of titles are ‘creative’, and always some complaints. Some people get it, some people don’t, it’s tough to visit a site, expecting everything to be objective, literal, an accurate. Hacking isn’t work, it’s something most people do for fun, the challenge. We live all the stiff living stuff at our paid jobs. The title may be misleading, but it very accurately describes the article, which includes both 3D printing, and glass. Maybe not directly printing with glass, but you still get a 3D printed object, in glass, instead of plastic. Headlines are suppose to grab your attention, get you to read the article. An artist tries to provoke an emotional response, doesn’t matter which emotions, only their work makes you feel something strongly enough to share with others. You experienced art, and you learned about a potential use for your 3D printer, seems like it got the job done quite well.

  2. Dear Al,
    the headline of this article left me very confused and disappointed, which I think isn’t fair to the person who did the actual project. Which is really cool and interesting.

    Because a headline stating “3D Printing Glass” is very misleading (which is an understatement).
    The hackaday headlines (in many cases) have some sort of pun, punch, or joke. They contain a hint not to take it too seriously. So knowing that I should have known, I guess.
    But this headline is none of that. It clearly states, without a doubt, that the article is all about “3D printing glass”.

    If the mold was made using nothing but playdoh and a set of skilled hands, would the headline have been “molding glass with your hands”?

  3. It’s not possible to cast large glass pieces in a microwave kiln – you have to cool it very slowly for several hours or even days to prevent destruction

  4. If you want to see actual 3D printed glass, there are two approaches I am aware of. MIT recently got a lot of exposure for extrusion-type glass printing, which produces nice decorative sculptures, but is pretty far from optical quality:

    https://www.youtube.com/watch?v=IvcpbtpWpGY

    More promising for serious applications is this approach by a German team of material scientists:

    https://www.nature.com/articles/nature22061

    Basically, you 3D print with a fused silica nanocomposite, which behaves like a photo-curable resin. Then you bake the printed structure to burn out all the non-silica components, and you are left with a pure fused silica glass object. The part shrinks during that process, but if you can correct for that in the design, then the quality seems to be quite high.

    1. The second method is just sintering. The (not very) unusual thing is that the green part is 3D printed.
      As I understand, the problem with that is, you can’t ensure, there will be no voids. It’s OK for 99% of the time, and it’s great for most of the applications, but for those, cheaper methods are already used.

  5. Add me to the “I hoped this article would have been some sort of CNC glassblowing machine” camp. Traditional glasswork would already fall under the “additive manufacturing” category for a lot of operations, and I was hoping to see somebody had rigged a 3D printer to torch and heat glass rods to add it to a model. The cooling challenges with this would be non-trivial, since unequal cooling can easily shatter your workpiece.

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