In order to reduce the mass of the Ford GT, the company worked with Corning to develop a Gorilla Glass hybrid window laminate that saves about 30 percent of the weight of traditional glazing.
One of the tests used during the development of the material was firing projectiles—in this case a chunk of ice—at the glass to determine its strength.
Hau Thai-Tang, Ford group vice president, Global Purchasing, says that in addition to being responsible for sourcing some $100-billion per year in goods and services, his team also works to “identify promising new technologies.â€
One of which is the auto industry’s first-ever deployment of a material that is familiar to users of smart phones and tablets: Gorilla Glass from Corning (corning.com). The material has been used for more than 4.5-billion mobile devices from 40 brands worldwide since its introduction to the consumer electronics market in 2007.
Ford is using Gorilla Glass as part of a hybrid material for the windshield, engine cover and an acoustic separation panel in the bulkhead for the Ford GT. (The side glass isn’t the hybrid material.)
Thai-Tang explains that there are three key aspects that Ford designers, developers and engineers have concentrated on as they ready the Ford GT for this year’s Le Mans:
• Powertrain
• Aerodynamics
• Lightweighting
And it is for this third category that the hybrid glass structure comes into play, as does the carbon fiber and aluminum materials that are used for the Ford GT*.
In this case, Thai-Tang says that the weight reduction provided by the hybrid glass structure is going to be on the order of 30 percent, or 12 lb., compared with conventional annealed glass laminate.
According to Paul Linden, Ford body exterior engineer who worked on the project, the Ford GT glass is “the lightest automotive glass in production.â€
The sandwich consists of a 2.1-mm thick soda-lime glass outer, a 0.76-mm acoustic polyvinyl butyral (PVB) middle, and a 0.7-mm Gorilla Glass (an aluminum silica material) inner.
Why have the strong, scratch resistant material on the inside rather than on the outside? Linden acknowledges that this seems counterintuitive, but they discovered through projectile testing that they needed flexibility on the outside surface and the strength on the inner.
The hybrid glass is anywhere from 25 to 50 percent thinner than conventional laminate, which accounts for the weight save. According to Corning, the automotive-grade Gorilla Glass, which it worked with Ford on developing, is, pound-for-pound, five-times stronger.
Another interesting aspect of the material is that unlike conventional automotive float glass, there are no optical draw lines on the material. Not only does this facilitate making a steep windshield for the Ford GT, but the optical clarity also facilitates using the surface for a heads-up display screen.
Thai-Tang acknowledges that the Ford GT represents limited production. He points out that for volume cars like the Focus, the glass system is on the order of 80 lb. and it is about 100 lb. for an Explorer SUV. Clearly, saving some 30 percent of that mass would be exceedingly important as Ford pursues more weight-down efforts as the 2025 CAFE regulations become ever-closer.
And while Gorilla Glass may seem to be a niche material, realize that before the 2015 Ford F-150, so did aluminum.—GSV
