Falorni Tech Glass Melting Technology

ExactaBlend improves bonding and sealing speed for Viracon

Insulated glass manufacturer Viracon uses a two-part structural glazing sealant for insulating glass (IG) production on large and high-profile building projects around the world.

Since installing the Graco® ExactaBlend™ AGP Advanced Glazing Proportioner, Viracon has increased production by 20 percent and achieved quality, health and safety and environmental benefits. Viracon had been using an older mechanical technology that could go off-ratio with mechanical failure and had no feature to alert operators of an off-ratio situation. The company was looking to improve productivity by increasing the speed process speed.
Viracon, based in Owatonna, Minnesota, produces insulating, laminated, and monolithic glass products for large building projects. The Freedom Tower at the new World Trade Center, the Minnesota Vikings’ Stadium and many of the major Las Vegas casinos are just a few of the well-known buildings in which their glass is found – including at least 5 of the world’s 10 tallest buildings. To succeed at this level, on-time delivery and superior quality are critical.
“We don’t have the luxury of delaying projects,” said Steve DeNeui, Viracon’s senior IG manufacturing engineer. “We work on high-profile jobs and they must be delivered complete and on time. We do not want other contractors waiting on us. We carefully monitor our on-time deliveries and if they fall below 95 percent, we hold a series of meetings to get back on track.”
DeNeui said that the Freedom Tower pushed Viracon to its limits due to the sheer size of the units required – 165 inches tall by 60 inches wide. In fact, the bottom stories of the building had specifications beyond their capabilities, and they were disappointed when a foreign competitor got the bid. “As it turned out, they were unable to deliver on their commitment, so the substrate used on the bottom floors is not glass. Therefore, we are honored to be able to say we have all the glass on the Freedom Tower!” He adds, “As far as the glass for the Vikings’ new home, while it is not our biggest project, we want all the projects in our own back yard and we are proud to be supporting the home team.”
A variety of traditional mixing and proportioning technologies exist, including pneumatic, positive displacement piston, mechanically linked proportioner and passive metering proportioners.
Viracon uses robotic equipment for dispensing silicone on four production lines, but there are certain applications that must be done by hand. For example, four-sided offsets, where all four edges are bigger on one side, must be sent to the hand-fill line. With a four-sided offset unit, the width and height of one sheet of glass is larger than the sheet of glass it is glued to, with the smaller glass facing the interior of the building. In this way, the glass covers the metal extrusions placed on the outside of the building, so only glass will be seen from the exterior of the building. A great deal of craftsmanship goes into these units and the glass sealant is critical to the unit’s final quality.
For nearly 25 years, Viracon had used a severe-duty plural-component proportioning and dispensing system for their hand-filling lines. The system was robust and reliable, but had begun to show its age.
In addition to delivering an inconsistent flow, it lacked real-time mix information. There were weekly issues of having to recheck materials, resulting in downtime while waiting for ratio samples.
Production speed was too slow, and reliable and robust equipment was required. Viracon runs nearly around the clock and needs a real workhorse, since the plant rarely shuts down. “We did not want to compromise with replacing the old tried and proven equipment with cheaper-made, easily broken equipment.”
These requirements led the company to the Graco® ExactaBlend™ AGP Advanced Glazing Proportioner, a new technology specifically developed to improve real-time ratio assurance, reduce material usage and enhance tracking of key information.
The system allows operators to set up and make ratio changes with a touch of a button. Operators can make ratio changes on the fly, allowing production to continue even when material requirements vary.
With positive ratio assurance, if off-ratio conditions exist, the system automatically shuts down to prevent compromised material from being dispensed onto the curtainwall or insulating glass, which gave them confidence they were producing a high-quality product.
The technology provided Viracon with high-pressure, high-flow mixing and dispensing of plural component silicone materials. The applicators deliver variable ratios between 6:1 and 14:1, and can perform at flow rates up to 4000 grams per minute.
Material usage, error reporting and other key data can be downloaded via USB, and/or viewed easily on the system’s data screen. This information is vital to keeping material costs low, tracking production and ensuring product quality.
To avoid system downtime when adhesive materials run low, the system provides advance notification, prompting operators to replenish the material supply and keep production moving without interruption.
The system uses standard Graco components, including fluid regulators, flow meters, air motors and pumps. Standard wear components are less expensive than custom parts and can usually be shipped immediately.
Viracon is now running material at a rate that is 20 percent faster than the older equipment. Exact return on investment (ROI) calculations are difficult, since the Minnesota plant does not have a standard size or type of product that lends itself to easy before and after comparisons. In fact, DeNeui calls the company “…the world’s largest Ma and Pa shop.” He adds, “Everything here is specific to the customer and their unique demands, so one day of product running through the facility rarely, if ever, mirrors the next day.”
While this makes it a bit difficult to measure the improvements with the new ExactaBlend AGP, DeNeui is quick to point out that the efficiencies have resulted in a big improvement to the bottom line. In fact, after the initial purchase of two Graco ExactaBlend AGPs, Viracon has since purchased additional units for their Utah plant.
The Graco ExactaBlend system has also resulted in significant ergonomics savings and health improvements.
It has also resulted in quality improvements stemming from continuous monitoring of the product mix. In addition, the equipment has environmental and energy benefits. While extremely robust, it uses fewer cubic feet per minute (CFM) than the older equipment, reducing energy usage. Viracon is also benefiting from other key, positive aspects of the new equipment. Tops on the list are ease of maintenance, parts availability, training of maintenance staff and equipment operators, and the ease of operation and trouble shooting.
The Graco ExactaBlend has far fewer moving parts than their old system. “Any time we can flow sealant faster, with a higher level of confidence, and not have to shut down production to sample, we are increasing productivity. And any time you combine increased productivity with increased quality, everyone is happy. This is the first radical change Viracon has made to our hand-filling equipment in my 24 years here, so this is huge. It has been well received by everyone, from our maintenance group to our equipment operators and up,” said DeNeui.

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