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PCs – Taking Gla the Simple Wind Silicon. One of the Earth’s most prolific substances, yet so important in our 21st century lives – from computers to disc technology – and glass. F ar from simply being a seethrough flat sheet, these days glass is often shaped and ‘valueadded’ to suit many applications. You would know glass can be produced to block or reduce heat, glare or noise (or a combination of all three). It can be tinted, it can be one-way, it can be patterned. But these days, thanks to the humble PC, glass can be so much more. Much of the glass enhancement would be infinitely more labor-inten- sive, expensive and complex – in fact, may not even be possible to produce – without computers. Here we look at a major glass supplier’s use of computers to help manufacture some unique products. DMS Glass in Melbourne is one of the largest glass enhancement manufacturers, producing products that we often see but usually don’t appreciate the technology employed to make it. Like not being able to see the wood for the trees, glass is traditionally some- thing you look through, not at. DMS Glass’s vast plant has made glass for sites like the Olympic Games facilities at Homebush, Hong Kong Airport, Crown Casino, Rialto tower, Melbourne Entertainment Centre, Melbourne Museum and Flemington Racecourse, to name a few. Just some of the products they make include laminated (toughened) glass, ballistic (bullet-resistant) glass and Digiglass, a laminated, printed glass invented in Australia. The convention Centre at Darling Harbour, Sydney has DMS Enviroshield laminated glass in the large picture windows. This product was chosen for its excellent heat control properties and high light transmission. 10  S 10 Silicon ilicon C Chip hip siliconchip.com.au ass Way Beyond dow Pane! By Kevin Poulter Each manufacturing step (and indeed the whole plant) is controlled by ‘mid-weight’ PCs or higher-power specialty computers. This results in some huge machinery controlled by modest size computers. Toughened glass Toughened glass is manufactured by exposing ordinary annealed glass to extremely high temperatures in an oven prior to entering a chilling chamber. This process induces stresses within the glass that enhance the panel’s strength by approximately five times. A PC controls the speed, time and temperature of the glass when it is in the various phases of the toughening plant. Laminated glass Laminated glass is manufactured by inserting a Poly Vinyl Butyral (PVB) interlayer between two sheets of glass, with the clean-room environment ensuring blemish-free glass. The assembled glass is transferred to an oven and roller press (to force out any trapped air) via an automated roller system. Computer sensors detect the glass movement, with a PC controlling the production-line flow. The laminated glass is exposed to temperature and pressure in an autoclave to finalise the bond. When laminated glass has more than two glass panes, a PVB interlayer is placed between each glass layer. Stopping a bullet Ballistic glass is a laminated glass with multiple layers of glass and interlayers, designed to remain intact after attack by bullet, hammer, axe or similar weapon. This glass is also used for prison windows. Some ballistic glass is designed to maintain integrity against blast. It is manufactured in accordance with Australian/New Zealand Standards AS/NZS 2343. The thickness and quantity varies depending on the ballistic threat level. No one ballistic glass is suitable to meet all levels of ballistic threat and therefore a ballistic glass designed to protect against a 9mm pistol threat is considerably thinner than glass designed to withstand a .357 Magnum. Part of the AS/NZS 2343 compliance requirements are that the sam- ple glass panels are shot three times within a set spacing with no ‘spall’ fragments penetrating a paper backing. I attended a number of ballistic glass tests, in a discrete underground firingrange in Melbourne’s suburbs. Few neighbours would know that below a small factory, firearms are used for tests or training most of the time. The glass resisted the best efforts with all kinds of firearms, with bullets and axes not managing to open a hole. There was plenty of cracking but there was no way that anyone could enter a building protected by this glass – even when the number of shots exceeded test parameters. Blast-resistant glass is far more challenging to develop, due to the uncertainty of the size and position of the bomb, plus the associated forces. Extensive, detailed tests are carried out to design a glass capable of withstanding the worst case example. Digiglass DMS’s own printed and laminated Digiglass is an amazing product. The industry historically has never been very inventive at decorating with glass but this medium has certainly opened This is the result of a high-powered weapon shot. The glass is marked, but still intact. Ballistic glass is laminated glass or multiple layers of glass and interlayers that vary in thickness and quantity depending on the ballistic threat level. siliconchip.com.au March 2007  11 Very little glass is either cut or processed by hand these days. The human operator has been replaced by PC consoles in nearly all aspects of order entry, glass cutting, edgeworking, drilling, laminating, CNC precision notching, toughening and water jet cutting. It’s staggering to see the impact of computers within the DMS 60,000 square metre factory and the glass industry in general, in the last ten years. The internationally patented Digiglass process digitally prints images directly onto a specially formulated PVB interlayer with compatible inks which are resilient to UV fading The digitally printed interlayer is then laminated between glass panels, encapsulating the image between glass, protecting the image for the life of the panel. up whole new areas – memorials, mausoleums, decorating skylights, features in walls or entire cladding of buildings. DMS glass international Marketing Manager, Gerard McCluskey and inventor of Digiglass, said “We are continually taking the product into Toughened glass is manufactured by exposing ordinary annealed glass to extremely high temperatures in an oven prior to entering a chilling chamber. This process induces stresses within the glass that enhance the panel’s strength by approximately five times, compared to annealed glass. The PC controls the speed, time and temperature of the glass when it is in the toughening plant. 12  Silicon Chip new areas, where glass has never been before”. “Our role is creating an understanding of what its capabilities are. Historically glass has always been perceived as a product that keeps out the wind and rain. Now with the latest techniques and manufacturing processes, it can achieve a lot more.” Five years ago, screen-printing or adhesive films were used to place images on glass. The adhesive method was high maintenance and deteriorated quickly. The solution was simple in concept, if not in the development. For years, DMS has added a film lamination to the centre of glass, for strength or UV control. Then in a stroke of inspiration, Gerard McCluskey experimented with adding ink-jet print onto the interlayer. McCluskey continued: “We ran some experimental prints and got a fantastic result, so I thought ‘what are we onto here!’ There were problems with adhesion, because the inks contaminated the surface of the interlayer, so another uncontaminated interlayer was placed on top. Now with two uncontaminated interlayer surfaces against the glass, we achieved very good adhesion.” The rest, as they say, is history. The internationally-patented Disiliconchip.com.au Glass orders from perhaps many customers are loaded on a PC for ‘optimisation’, for the lowest-waste layouts. This is a vital step in efficiency and economy. The computed data is fed to the cutting table at right. A diamond-tipped wheel zips around the glass at great speed, cutting the shapes. A sheet of glass is easily moved on the table, as air is fed through a pattern of holes, making the glass ‘float’ easily on command. When in the correct position, the airflow is reversed, with the suction holding the glass firmly in place. Some tables rise to vertical, allowing vertical storage of the glass until ready for shipment. giglass process consists of digitally printing images directly onto a specially formulated PVB interlayer with compatible inks, resistant to UV fading when glazed externally. The printed interlayer, in high-resolution full colour, is then laminated between Grade-A safety glass panels, encapsulating the image and protecting it for the life of the panel. This technology is now sold around the world. McCluskey is excited with the Digiglass versatility. “The beauty of our product is we can produce a panel today and replicate it in 10 years time for whatever reason. If it needs to be replaced we can make a copy, or even change the colours or tonings to match it to the latest surroundings.” DMS established worldwide patents but not possessing the international clout to rebuff copycat interlopers, engaged DuPont to market the product outside Australia and New Zealand. Now buildings and features such as the Memorial to the Canberra Bush Fires and many in USA feature Digiglass. the data is forwarded by cable to a very large ink-jet printer deep in the factory. Even the inkwells make a home printer seem tiny! The image or pattern is printed onto the interlayer film, in a dust-free environment. Specially developed proprietary inks and interlayers are used in combination to offer the ideal adhesion, resolution, and dimensional properties needed. The printed film is then taken to the laminating-room, a clean room with a multi-million-dollar computercontrolled laminator. Being PC generated, last-minute How it’s done A graphic artist makes the image graphic file on a PC, then the file is loaded into a DMS PC for formatting. Graphic file sizes can be as large as 1GB. Once formatted for production, siliconchip.com.au Some glass is cut by a high-pressure jet of water. Water jet cutting of glass is a relatively new innovation and is extremely efficient when cutting multi-ply glass laminates or complex shapes. Again, the process is controlled by a PC. March 2007  13 changes and previews, such as four different color versions of the same image for comparison, are no problem. Applications are as varied as the imagination – even bus shelters, where Digiglass creates a feeling of openness and cleanliness, while still offering people a good view of approaching buses or people. Even vandalism seems to have been reduced – as soon as Digiglass started putting images within glass, less panels needed replacement. Perhaps it was because the glass was now telling a story, it had a theme or had a pictorial image and was no longer something simple to be destroyed. Beauty and brains. Digiglass is visually dramatic and beautiful, plus just as strong and practical as any glass. The product meets AS/ NZ 2208 Grade A Safety Glass standards. A very successful but initially unanticipated application is Digiglass images in laminated glass memorial products. The product has been recognised by DuPont in the Australian and New Zealand Innovation Awards, as a finalist in the Construction and Architecture category. The walls in the lift at the new Mercedes Benz Melbourne showroom are Digiglass, displaying their notable sports cars. Located in South Melbourne, the showroom is predominately a steel and glass structure, designed to convey the sense of quality associated with the automobiles on display. The outside of the building is DMS Enviroshield Sunergy Clear Heat Strengthened Laminate. The 12.76 mm laminated glass, which incorporates XIR 72-74 film by Southwall Technologies, created a neutral colour, energy- efficient product with exceptional solar and thermal control properties. The glass has an exceptionally high light-transmission of 72% to maximise daylight, while offering increased comfort and superior reduction in solar heat gain (0.47 solar heat gain coefficient) and minimising outside noise. Glass is a very unforgiving product. It is unlike any other building product. It’s brittle but it’s probably the most hard-working and long-term building product; one that needs very little maintenance. When processed for strength, it’s suitable for stairs and walkways, or even for armored vehicles. Computing power Until the 1980s all glass processing, including cutting and edging, was done by hand. The skills of the tradesmen had to be at a very high level but now, with advances in computers and electronics, hi-tech methods of cutting and edging glass are employed. One area where PCs now save time and money is optimisation. For best efficiency and economy, the ‘jigsaw’ shapes of a number of orders are placed into a computer program and the best use of the available sheet-glass area is plotted. This enables the biggest sheets of glass to be cut into shapes for two, five or even ten different customers. The computer optimising application can reduce the off-cut factor down to a minimum, with a waste factor of 5% regularly achieved. The fully automatic glass lamination process. In the white room environment, which ensures cleanliness and a blemish-free glass finish, glass is assembled either side of the PVB interlayer. This is then transferred to an oven and press via an automated roller system, controlled by computer sensors detecting the glass movement. 14  Silicon Chip siliconchip.com.au Most often the large sheets of glass are cut into customer-ordered oblongs but any conceivable irregular shape can also be cut. To order irregular shapes (for example a peanut-shape tabletop) designers supply a precise template in wood. The template is photographed, then goes into a CAD system. If out of square or irregular, shapes and dimensions can’t be taken, a probe is used to touch multiple points, automatically sending data back to the computer and rapidly creating the overall panel dimensions. The optimised and shape data is fed into the cutting and/or hole-cutting machines’ computers. Cutting and hole drilling is achieved either on a rapid diamond-cutter, the immensely powerful water-jet cutter or hole drill. With the latter, holes are drilled from both sides at the same time, to avoid burrs and chipping Precision drilling of glass is vital for accurate installation of fittings such as handles, hinges, etc. All processing of glass must be completed prior to the toughening process as once toughened it is considered a finished product. These computer-driven drilling, notching and routing machines offer pinpoint accuracy. (known as ‘shelling’). With the table-type glasscutter, a single operator can glide a huge sheet of glass into position with ease, thanks to a cushion of air. A multitude of holes, all about the size of drinkingstraws, are fed air under the glass. This enables the operator to ‘glide’ the heavy glass into position. Then the air is evacuated, holding the glass firmly and precisely in place. While their hole-cutting CNC machines make a complete cut, the shape ‘cutting’ tables only score the outline, so most glass-cutting tables now have automatic breakout capabilities. An air-driven foot pump activates bars that rise up underneath the scored glass, to push the cuts apart. Some tables rise to vertical, allowing glass to be stored vertically, until ready for shipment. Tracking the glass Large manufacturing plants need to track orders to ensure timely completion, schedule production, optimising and capacity planning. DMS glass has introduced a barcode system, so each step is ‘read’ on completion and automatically recorded into the server’s files. Heat treatment will dislodge the barcode, so at a number of stages, the stickers are removed and subsequently replaced with new stickers after treatment. The advantages of barcoding are many, such as quick reordering a part if it does not pass inspection and maximis‑ing the output and efficiency of production machinery. Computers are integral right through the manufacturing process and even include DMS glass The recently-finished Mercedes Melbourne Car Showroom chose delivery. As the trucks make their way to the Digiglass to depict vehicles of various eras in the showroom lift. The Digiglass mural only requires routine cleaning, as the image is clients, they are monitored on screen by a Global Positioning System! protected within the laminated glass. SC siliconchip.com.au March 2007  15