Aug 19, 2016 | By Alec

Over the past few months, Russia has been making quite a few 3D printing headlines – but mostly in the context of metal 3D printing for aerospace and nuclear applications. But Russian PhDs Anuar Kulmagambetov and Vladimir Bodyakin are moving into an entirely new direction with a remarkable patent application. With an eye on the construction industry, they are working on a 3D printing setup that can build durable walls and structures from glass, using a compact glass melting furnace as an extrusion unit. The researchers are currently looking to set up a pilot, and see significant cost-saving and environmentally-friendly opportunities.

The world is only just starting to get used to the idea of 3D printed concrete houses and buildings, in part thanks to the groundbreaking work of companies like WinSun, but this remarkable patent (filed earlier this year) essentially proposes to replace that concrete with glass. That’s right: glass. While it sounds unbelievable, the Russian researchers have explained that glass could actually be a much more useful and flexible building material than the concrete we are all used to – especially when 3D printed. “Concrete 3D filling requires the addition of fiber and chemical additives to its composition to reduce the setting time which leads to a reduction of the adhesion level between the casted layers etc.,” they explain. What’s more, it can be relatively expensive.

Glass, on the other hand, is easy. While we only know it in thin sheets, it can actually be 3D printed in any shape or form. “Molten glass has a high level of viscosity, hardens fast and has good setting characteristics. The walls can be poured of different densities from low (foam glass) to high density of 4000 kg / m3. Multi-layered walls can be cast with high quality finish such as color, density, surface structure, light-reflection, thermal conductivity and other characteristics,” they say. These options have all recently come out of glass melting innovations, and present the builder and architect with plenty of construction flexibility.

Most importantly, its ‘filament’ is the most eco-friendly, natural and widespread material in the world: silica sand. Combined with with sodium bicarbonate, dolomite, lime and other additives (depending on the application), it is very cheap and adaptable. But it doesn’t end there. Glass is also very resistant to decay, mold and humidity, requires very little maintenance and is quite energy-efficient to produce.

That sounds a bit better already, but how would it be 3D printed? As Kulmagambetov and Bodyakin explain, they envision a 3D printing process in which raw stock is constantly fed into a glass furnace. The furnace itself is the extrusion unit, meaning that its power supply and heat dissipation systems constantly move with it – something they believe is not difficult to achieve. The furnace itself can be fully electric or part electric, part gas heated, with a capacity of anywhere from a few liters to several cubic meters.

With such a setup, any part of a structure could be 3D printed, including walls and floors – with a plasma torch used for a smooth exterior finish. They are even envisioning using several types of glass furnaces (with different internal structures or nozzle shapes) in a single 3D printing setup, which can be prepared beforehand for various applications, such as dense wall 3D printing, foam glass 3D printing, or even simultaneously casting several wall layers with different finishes and colors.

What’s more, this setup doesn’t deviate far from the standard 3D printing conventions and is easily modifiable to suit each and every project. For instance, a stationary glass furnace can be operated near or on the construction site, to produce stock and optimize efficiency through minimized melting times. “Unsorted or waste glass can also form the stock basis. For additional reinforcement, carbon fiber or small s-shaped pieces of metal wire can be placed into the glass melted walls,” they add.

The Russian developers are also seriously looking at high quality industries where the superior qualities of glass make it a very potent alternative to concrete. Among others, glass offers far better protection against radiation, while it is comparable to concrete in terms of flexibility, integrity and maintainability – making it a good option for nuclear power plants. 3D printing can even be used to create vacuum conditions within the glass, making it very isolating and a fantastic option for the inner walls of refrigeration units and warehouses– greatly decreasing the costs of cooling processes.

Finally, they even believe that hospitals can greatly benefit from 3D printed glass walls. “It is widely known that antibiotics-resistant viruses can settle on the walls of hospitals and it is impossible to eliminate them without removing a layer of the wall. Walls have a porous structure and standard disinfection methods do not work well,” they argue. Glass, however, can be easily treated with numerous light or gas-based solutions to sterilize any room.

Glass is thus beginning to look like a very good option, though it will doubtlessly take some time to convince the world that it is as strong as concrete. To do so, the Russian researchers are currently looking to start a pilot program with an external company. With a 30-liter furnace, they say, they can already start to build walls. Move over concrete, glass is on its way.

Posted in 3D Printing Technology

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WillieNAZ wrote at 1/22/2018 1:26:54 AM:Could even use a soldering iron to make holes in it for IR LEDs to help disinfect the walls in a hospital. For a home I'd want a 4 foot square section of wall at both ends made of adobe block just so the house can naturally breathe. Awesome work. I wish I had one of those houses.Anuar K. wrote at 8/25/2016 8:33:40 PM:This comment was left in Reddit and I saw it just now. Therefore, I transfer it to the main window for all to see. I want to thank the author for the opportunity to provide further explanations. Comment left in Reddit by tm_glass: A bit of a bogus headline imo. Two reasons, one being that glass walls are already a reality, we generally call them windows. Kind of a contrived way of solving a problem that was solved in the 1950s with the invention of the float glass process. Anuar K: Unlike windows walls must hold on weight of the entire upper part of the house. This problem is not solved as windows cannot be carrying this function. The known float technology has nothing to do with us. Translation sensitivity to English language rises some misunderstanding. We are not talking about glass, but the glass melt (substance we get between the batch and pure glass stages). Production of glass is a long process which includes 5 stages. The glass melt we get at the first stages of the glass making process. For glass production such characteristics as glass transparency, purity, homogeneity are essential. For the glass melt IT IS NOT. To get glass we need to melt the batch for a long time, depending on its composition, which makes 3D printing process by glass extremely long which is unacceptable for us. Therefore, we are not talking about the glass in its conventional meaning. But about the glass melt (glass mass). It is like we would stop a large glass furnace (here it is an old-style glass furnace), then unmolded or flawed residues would be discharged, but the solidified glass weight would be left. And in order to empty the tank you need to spend a few days to break away this solidified body. Comment (continue): Second, MIT already did this (3d glass extrusion print) in 2015. One of the problems with glass manufacturing is stress created by heating and cooling (leading to cracks.) The MIT project solves this by extruding into an annealing oven that is above the stress point but below the softening point of the glass. Sure it is possible to engineer a glass of low coe (coefficient of expansion) that wouldn't generate stress cracks but the trade off is much greater expense and higher melting point, enough to make such a process extremely expensive. (If anything the way to do it would be sortof a reverse lehr kiln with a moving annealer but it would be SLOW.) Also, it would be somewhat unlikely to batch glass on site from sand and raw materials, if anything there would likely be a feedstock of rod or cullet. Anuar K.: As we mentioned before we are working with the glass melt. But MIT works with glass. These are two different things. MIT uses a heated container, and we use a glass melting furnace. These are also two totally different objects. In the figure we show the induction furnace with batch feeding system, heat dissipation system (water) and power supply. Why do I assume that MIT does not melt the glass but heat it? Extrusion of glass requires high pressure conditions to be created inside the container, but during the glass melting process gases are generated (bubbles). On the exit the bubbles would have just grown in size and spoiled glass. So I suppose that high-quality glass is fed into the container and high-quality glass is also obtained at the output, because the goal of the 3D print head is to create small size glassware (vases, jars, etc.). Glass portions are small and single served, instead of the flow as we have. In that case all the components of melt are important - its cleanliness, play of color, reflections, melt quality, clearness and absence of defects. These do not matter to us. What important is the casting speed and the glass melt strength. I hope now it is more clear in terms of the “glass” house. Annealing and toughening of glass are known stages. Thermoelastic stress in glass is an old and solvable issue. Example: in case of line molding of glass bottles annealing is required and it is a small and quick stage. Here, when adjusting the technological regime, it is important to accurately observe the temperature regime - to conduct annealing at a temperature higher than the molding temperature. This can be done quickly, because the annealed glass melt layer is small. You are confused by float technology. We have independently heated nozzle. Comment (continue): The suggestion that such a printer would run on a mix of used bottles and waste glass is also unlikely considering that mixed glass generally not compatible due to the differing COE as well as differing viscosity at a given temp. Anuar K.: Your comments concerning the coefficient of expansion of different glass, these are important when we combine glass. For example, concerning MIT container your words are true. But we melt glass, and it is a very different kind of interaction. Given that the melting stage with abandoned gas emission is already passed in cullet it is a valuable material to us. It speeds up the cast process and allows to pour dense walls layers. Comment (continue): “I could go on, but my point is: I would love to see a glass 3d printer as much as anybody but there are fundamental engineering issues that are not addressed in this supposed "reality"-- this is a very rough clickbaity sketch at best, and obviously by someone with more 3d printing experience than glass knowledge. Anuar K.: For casting walls we cannot apply MIT technology. It is good for designers and can produce beautiful small objects. But for construction of glass melt houses we need a different technology. We have high loads, huge amounts of batch moved (not 1 liter of glass but 50 m3 of glass mass), thermal conductivity requirements, density etc. Therefore, we print dense layers as well as layers of foam glass. We have completely different objectives, methods and technology.Anuar K. wrote at 8/23/2016 2:09:20 PM:We prefer to use the term glass melt because we will apply the accelerated glass melting process. Since the vertical layers cast with different densities so several furnaces are used for molding dense layers and layers of foam glass. Certainly, the issue of removing thermoelastic stress inside the glass is resolved by taking consideration of: the thickness of the filling layer (which begins with a few millimeters), the size of the wall, the composition of the charge, the furnace operation regime, the additional heating need, residual stress control etc. The issue is resolved at the stage of adjustment of technological casting regime. It is important not to draw analogies concrete 3D printing.Ken wrote at 8/21/2016 6:23:33 PM:What about cooling the class to keep it from cracking?



