Well, we know they had sand...so why not glass? The palace-city of Samarra, capital of the former Abbasid Caliphate, was home to an advanced industry of glass production and trade, according to a study published August 22, 2018 in the open-access journal PLOS ONE by Nadine Schibille of the CNRS, France and colleagues.
Light-flooded spaces and a general airiness in buildings are no longer just a trend in the architectural world, but are increasingly state-of-the-art. This general airiness achieved through the use of transparent materials does not end with the balcony. Total vision glazing and glass balustrades can offer continuity to wide open spaces, if they are not interrupted by framing or other mechanical fixations. When it comes to connecting glass to frame materials, new solutions are coming to market every day.
Glass Performance Days, a biennial conference held in Tampere, Finland, has released an entire online book full of educational articles provided by its session presenters. The 457-page document contains 91 white papers, each connected to an educational seminar that took place at its 25th event in June last year. The papers discuss just about every imaginable topic in the architectural glass industry.
Carbon fibre composite remains too expensive and slow to process for widespread use as a building material. But trends both on the supply and demand side are perhaps bringing it closer to feasibility. The material’s strength-to-weight ratio, corrosion-resistance and low thermal conductivity make it an intriguing possibility for very high-end projects demanding low sight lines, big glass and good thermal performance.
Let’s take a look at the recent great work by our Technical Services Committee, chaired by Jeff Haberer of Trulite Glass and Aluminum Solutions.
Glass and glazing elements like most primary construction materials including concrete, masonry, metals and plastics have benefited a great deal from improvements in advanced coating technologies. The use of advanced coating techniques and materials to improve appearance and performance of glass in particular has proven to be a constant source of successful innovation over time.
Stunning unbroken views of vistas or store interiors – that’s the demand driving the production, shipment and installation of large panes of glass today – panes as much as 20 feet across and thousands of pounds. Agnora, the largest-capacity glass fabricator in North America, has seen a tenfold increase in the demand for big glass over the last five years. Vice-president of operations Jeff Wilkins says this includes both storefront and residential markets right across continent. Agnora is able to temper, machine, laminate and insulate various thickness of glass up to a maximum size of 130 by 300 inches. The company’s two main challenges of with glass (float glass availability and shipping) have been handled, says Wilkins, through creating strong partnerships with suppliers and by working collaboratively with shipping partners. “Big glass is heavy and dangerous therefore we are very serious about our maintenance and upkeep of our lifting equipment and designing our work flow to minimize the amount of manual lifting,” he explains.
Dec. 14, 2016 - With a customized inloader, sedak optimizes the handling of oversize glass. The new 23m long inloader now delivers glass units up to 16m. The steerable rear axle which allows the truck to drive through narrow curves such as roundabouts is the key feature of the mega trailer. Due to its space-saving interior concept, no escort vehicle is required.
Everywhere you look today, architects are leveraging glass for daylighting purposes to allow the right amount of light into a building. But while much of the attention centers on the façade, interior spaces leveraging glass are just as critical to the introduction of natural light into the building environment. For interior space in particular, glass railing systems for stairways and balconies play a key role in letting the light in. And that means opportunities for glaziers with glass railings.
The U.S. Naval Research Laboratory uses a hot press to make spinel into conformable optics, like this flat sheet. “Ultimately, we’re going to hand it over to industry,” says Jas Sanghera, who leads the research, “so it has to be a scalable process.” In the lab, they made pieces eight inches in diameter. “Then we licensed the technology to a company who was able then to scale that up to much larger plates, about 30-inches wide.”Imagine a glass window that’s tough like armor, a camera lens that doesn’t get scratched in a sand storm or a smart phone that doesn’t break when dropped. Except it’s not glass, it’s a special ceramic called spinel that the U.S. Naval Research Laboratory (NRL) has been researching over the last 10 years. “Spinel is actually a mineral, it’s magnesium aluminate,” says Jas Sanghera, who leads the research. “The advantage is it’s so much tougher, stronger, harder than glass. It provides better protection in more hostile environments so it can withstand sand and rain erosion.” As a more durable material, a thinner layer of spinel can give better performance than glass. “For weight-sensitive platforms – unmanned autonomous vehicles, head-mounted face shields – it’s a game-changing technology,” he says.NRL invented a new way of making transparent spinel using a hot press, called sintering. It’s a low-temperature process, and the size of the pieces is limited only by the size of the press. “Ultimately, we’re going to hand it over to industry,” Sanghera says, “so it has to be a scalable process.” In the lab, they made pieces eight inches in diameter. “Then we licensed the technology to a company who was able then to scale that up to much larger plates, about 30-inches wide.”The sintering method also allows NRL to make optics in a number of shapes, “conformal with the surface of an airplane or UAV wing,” depending on the shape of the press.In addition to being tougher, stronger and harder, Sanghera says spinel has “unique optical properties. Not only can you see through it, but it allows infrared light to go through it.” That means the military, for imaging systems, “can use spinel as the window because it allows the infrared light to come through.”NRL is also looking at spinel for the windows on lasers operating in maritime and other hostile environments. “I’ve got to worry about wave slap and saltwater and things like that, and gun blasts going off. It’s got to be resistant to all that. And so that’s where spinel comes into its own,” Sanghera says. Says Sanghera, “Everything we do, we’re trying to push the mission. It’s designed to either enable a new application, a new capability, or enhance an existing one.”Spinel can be mined as a gemstone. A famous example is the Black Prince’s Ruby, which is actually spinel with a colour dopant. NRL chemists have also synthesized their own ultra-high purity spinel powder, and other synthetic versions are commercially available. “The precursors are all earth-abundant, so it’s available for reasonably low cost,” Sanghera says. The spinel NRL makes is a polycrystalline material, which means it is made of a lot of crystal particles all pressed together. With glass, “a crack that forms on the surface will go all the way through,” Sanghera explains. Spinel might chip but it won’t crack. “It’s like navigating through the asteroid belt, you create a tortuous path. If I have all these crystals packed together, the crack gets deflected at the hard crystals and you dissipate the crack energy.When scientists first started trying to make glass-like spinel, they were using a crucible instead of a press. “A big problem with growing crystals is that you have to melt the starting powder at very high temperatures: over 2,000 C,” Sanghera says. It’s expensive to heat a material that high, and “the molten material reacts with the crucible, so if you’re trying to make very high-quality crystals, you end up with a huge amount of defects.” That’s why Sanghera and his colleagues turned to sintering. “You put the powder in a hot press then you press it under vacuum to squash the powder together. If you can do that right, then you can get rid of all the entrapped air and all of a sudden it comes out of there clear-looking.” If the press has flat plates, the spinel will come out flat. “But if I have a ball and socket joint and put the powder in there, I end up with a dome shape,” Sanghera says. “So we can make near-net-shape product that way.”NRL was not the first to try sintering. But previous attempts had yielded “a window where most of it would look cloudy and there would be an odd region here and there – about an inch or so – that was clear, and that would be core-drilled out.”So NRL deconstructed the science. They started with purer chemicals. “Lousy chemicals in, lousy material out,” Sanghera says. Then they discovered a second problem, this time with the sintering aid they were adding to the spinel powder. “It’s about one per cent of a different powder, in this case lithium fluoride,” Sanghera says. This “pixie dust” is meant to melt and “lubricate the powder particles, so there’s less friction, so they can all move together during sintering.” They were putting the powders together in shakers overnight, but “the thing is, on a scale of the powder, it’s never mixed uniformly.” Understanding the problem led to a unique solution for enabling uniform mixing. Now, “there’s only one pathway for densification,” and the spinel will come out clear across the press.To further increase the quality of the optic, “you can grind and polish this just like you would do gems,” Sanghera says. This is the most costly part of the process. “One of the things we’re looking at is, how do we reduce the finishing cost?” The surface of the press is imprinted onto the glass. “If we can improve upon that,” he says, “make that mirror finish, then – and so that’s where we get into a little bit of intellectual property – what’s the best way to do that?”For both the Department of Defense and private industry, “cost is a big driver, and so it’s important for us to make products? that can be affordable.”Unique applications for military and commercial use“There are a lot of applications,” Sanghera says. He mentions watches and consumer electronics, like the smart phone, as examples. The military in particular may want to use spinel as transparent armour for vehicles and face shields. A “bullet-proof” window today, for example, has layers of plastic and glass perhaps five inches thick. “If you replaced that with spinel, you’d reduce the weight by a factor of two or more,” Sanghera says.The military’s also interested in using spinel to better protect visible and infrared cameras on planes and other platforms. Glass doesn’t transmit infrared, so today’s optics are made of “exotic materials that are very soft and fragile,” and have multiple layers to compensate for colour distortions. “So that’s what we’ve been doing now, developing new optical materials,” Sanghera says. Spinel windows could also protect sensors on space satellites, an area Sanghera’s interested in testing. “You could leave these out there for longer periods of time, go into environments that are harsher than what they’re encountering now, and enable more capabilities,” he says.NRL is also looking at spinel (and other materials) for next-generation lasers. “Lasers can be thought of as a box comprised of optics,” he says. “There’s passive and there’s active components. Passive is just a protective window, active is where we change the colour of light coming out the other end.” For passive laser applications, like exit apertures (windows), the key is high quality. “That window, if it’s got any impurities or junk, it can absorb that laser light,” Sanghera says. “When it absorbs, things heat up,” which can cause the window to break. Sanghera and his colleagues have demonstrated, working with “ultra high purity” spinel powder they’ve synthesized in NRL clean rooms, spinel’s incredible potential. For active laser applications, they’ve demonstrated how sintering can be used with materials other than spinel to make a laser that’s “excellent optical quality.” Instead of spinel, they use, “things like yttria or lutecia and dope them with rare earth ions.” NRL has transitioned both types of laser materials and applications to industry.
View the embedded image gallery online at:Editor’s commentAlternative transparent materials in appliactions that require high impact resistance would be a welcome innovation in architectural glazing. Many designers have been looking for solutions to problems with traditional safety glass products. One example that springs to mind is balcony glass. There have been several instances in big Canadian cities of tempered balustrades in high-rise condominiums shattering and showering tempered glass “pebbles” into the street below, much to the concern of passers by and unit owners. The breakages were blamed on the expansion and contraction of nickel sulphide inclusions in the glass which are introduced as a normal byproduct of the primary float glass process. Heat soaking can ensure a lower percentage of inclusions in the glass that survives the process, but adds waste and cost without completely eliminating the problem. New standards for balcony guard construction and the use of laminated glass will probably ameliorate the issue going forward, but at the cost of some design restrictions. Sintered spinel panels would presumably be much stronger, offering increased protection to residents and pedestrians. Another area where safety glass has become not-so-safe is wired glass. Primarily used for fire resistance, wired glass has come under scrutiny lately following instances of people impacting the windows and cutting themselves on the metal wire interlayer. If spinel can take the heat of a laser without shattering, a regular fire should cause no problem. Of course, the cost of producing architectural-size sintered spinel panels is prohibitive right now. Perhaps some form of additive manufacturing process would offer a solution, as some kinds of 3D printers operate in a manner very similar to sintering. Again, technology that is some years off. So were smartphones in 1995. Sometimes it pays to keep an eye on what is coming next. Reducing costsThe U.S. Naval Research Laboratory uses a hot press to make spinel, a process called sintering. It’s much less expensive than melting, and the size of the pieces is limited only by the size of the press. Lead researcher Jas Sanghera says, “You put the powder in a hot press then you press it under vacuum to squash the powder together. If you can do that right, then you can get rid of all the entrapped air and all of a sudden it comes out of there clear-looking.” To further increase the quality of the optic, “You can grind and polish this just like you would do gems.”
Design and Integration is what you might call a pure engineering company. Located in a nondescript industrial unit in Concord, Ont., Felix Gutnik and his team are quietly coming up with elegant solutions to common problems in glass processing automation without multimillion-dollar R&D budgets or any government support. All they really have is Gutnik’s lifelong passion for building and fixing mechanical things, and experience in the glass industry that now stretches back three decades. Design and Integration will probably build anything anyone asks them to, but their specialty is glass processing automation, including lamination lines, insulating glass assembly lines and material handling automation and equipment. They have provided a liquid lamination line with specialized tables for taping, tilting for assembly, filling and curing laminated glass units. That one was done in partnership with Uvekol.Film lamination was Felix’s introduction to the glass business through work he did with Kodak at a prior company. Over the year’s he’s come up with some nifty tricks for solving the notoriously tricky problems of automating film lamination. For instance, one design uses a two-level approach to achieve high-speed lamination even of irregular shapes. The line has two feeder conveyors, one over the other. One sheet is brought in and loaded into the top conveyor. The second is brought in and a worker places and trims the interlayer film. Then the bottom piece, with the interlayer on it, feeds through. As it emerges, the top sheet is precisely fed forward so that it droops down and its edge matches up with the edge of the bottom sheet. As the two pieces feed forward, the top sheet is gently laid onto the interlayer, with its weight forcing out any air between the layers. The system works just as well with round or odd-shaped glass as it does with rectangles. Design and Integration has also made a very cool cross-cut machine for quickly automating trimming on high-speed, mass production laminating operations. A panel of glass is fed under the film roller, which dispenses the film onto the surface. When its leading edge emerges on the other side, it hits a stop. A sensor stop drops down on the infeed side as the next sheet of glass comes along. When the second sheet hits the sensor, it pushes it forward until it hits the first panel. The sensor registers distance between the two stops, then retracts out of the way, leaving the two panels a very precise distance apart on the conveyor. The panels roll forward. As the back edge of the first panel emerges, a knife cuts off the film with almost no waste. At the same time, the second panel’s interlayer is placed. As long as each piece is long enough to reach past the film roller, panels of different lengths can have interlayer applied and cut without making any adjustments. Gutnik has also come up with a novel solution to curing PVB laminate without using an autoclave. The glass panels are put in vacuum bags and stacked on a large, portable rack that can hold dozens of sheets. The entire rack is then put into a lamination oven that goes through the necessary heating and cooling cycles to cure the interlayer. It takes about three hours to cure one batch. Meanwhile, a worker can be loading another rack with freshly assembled units ready for curing. The finished ones come out, the new ones go in and the baking can start again quickly. Gutnik likes this solution because it eliminates autoclaves and can make multiple large panels quickly. The slots on the rack he designed are 10 feet wide by 20 feet deep, and there are eight of them. The system has also been applied to a heat soaking application. So coming up with innovative solutions has never been a problem for Design and Integration. Gutnik credits his company’s size and the fact that the buck stops with him when it comes to engineering design. “Major companies have mechanical engineers, electric engineers, programmers, concept engineers, all this,” he explains. “The problem is, when a group of people try to develop a horse, sometimes it becomes a camel. Because I work in programming and electrical and mechanical and hydraulics, I design from one source. That’s why I have less screw-ups. But after 22 years in business, last year I made a major screw-up.”The screw-up Gutnik refers to is his attempt to develop a new kind of horizontal laminator for PVB, EVA and Sentry glass. The concept was to make a two-level system that would pass units through a compact furnace then automatically drop them with a scissor lift to a second level, right underneath, where they would be compressed in a press and heated again to achieve final bonding without an autoclave. The system could be designed with yet another conveyor level underneath the first two levels to let new units pass from the washer to a second inline laminator, effectively doubling the capacity of the line and taking all the product that a standard washer can put through. Michael Byrne of Explore One is familiar with Gutnik’s prototype. “The goal was to build a machine that was about 1/10th the cost of traditional laminating systems that would require no vacuum bags and be installed with a footprint of as little as 1,200 square feet,” he explains. “The system would give smaller shops the capability to produce laminated glass in a very cost-effective manner. It would also allow for an unprecedented level of flexibility from a pure laminated glass production perspective.”Into every development process, some rain must fall. Gutnik’s bad weather began with an order of hydraulic relief valves. In the system, hot and cold fluid runs through a large platoon which heats and cools the glass in turn. Both the relief valves and the backup relief valves proved to be faulty and caused an overload in the system, causing 400-degree oil to explode out, destroying a significant portion of his prototype. The wrecked hulk of the first prototype now sits in his back lot, covered in a tarp. Gutnik had invested about $400,000 of his own money in the prototype. With the destruction of his parts, it became a significant challenge to continue development. One option he explored was assistance from one of the government programs that are supposedly eager to lavish money on innovative small businesses. What Gutnik and his team have found is that these programs are in fact set up to reward large, existing R&D departments with dedicated staff and budgets and labs with people in white coats. The paperwork requirements alone are impossible for a small operator to meet. According to Andrei Lagounov, one of Gutnik’s sales people, one government R&D program required paperwork justifying the expense of almost every single part they bought to build a prototype. When he saw similar paperwork from a large engine manufacturer, he saw that it was allowed to justify whole large assemblies in one document because the parts involved were already in its existing R&D inventory. “How is a small company supposed to do that?” Lagounov asks. “We buy the parts as we need them, and we rarely know ahead of time what we are going to need.”Design and Integration has weathered the storm and come out dry and smiling. At September’s GlassBuild, it will unveil the fully functioning Lami ExPress, a glass laminating system that eliminates the need for vacuum bagging or an autoclave. The system can process units of varying thicknesses and sizes with a batch area of seven by 10 feet. Design and Integration is quoting an energy cost per load of $2 and a cycle time of about 1:15, depending on the PVB used. The unit comes with touch screen controls and a Samsung tablet for mobile control. The total space required is 36 by 10 feet.So it’s one hard-won victory for Design and Integration. One hopes there are more on the way and that, some day, the agencies charged with encouraging companies like this will find some way to actually do their jobs.
View the embedded image gallery online at:Concept to reality: the LamiExpressDesign and Integration’s LamiExpress will debut at GlassBuild America in September. It has the potential to save fabricators considerable time and floor space, and to make in-house lamination affordable for smaller shops. It is also optimized for integration into larger production lines. Laminates PVB, EVA or Sentry glass Multiple thicknesses and sizes can be laminated in one batch No vacuum bags, autoclaves or tac ovens Multiple layers can be applied next to single-layer glass Seven-by-10-foot total batch area Total footprint: 36 by 10 feet Design and Integration’s machines are built at the company’s facility in Concorde, Ont. Approximate delivery lead time is four months.
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