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July/August  2003

Off the Line
Jason Wright oem glass manufacturing news


Jason.Wright@us.pilkington.com

Design in the Future
by Jason Wright

Take a drive down any road in any city in America and I’m sure you will eventually see a recent generation sports car, truck, sports utility vehicle or minivan. I’m sure you, as I do, admire at least one of them for its sleek and flowing body design. 

As automobile manufacturers continue to impress us with new technological advancements and aesthetically pleasing designs, OE automotive glass manufacturers are tasked with the ever-evolving challenge of meeting auto glass design requirements that grow more complex every day. 

In addition, there’s the matter of applying technological advancements (glazing systems) to the glass itself. This also provides an exciting glimpse into future trends in auto glass and opportunities for manufacturing technology breakthroughs.

One of the most prevalent examples of challenges in design is the recent pushing of the limits of current windshield cross bend levels. The term “cross bend” refers to 
the amount of bending (egg-shape) applied to the glass. 

Cross bending has become increasingly common in recent years, but prior to the 1990s, cross bending mainly concerned backlites with relatively small bending radiuses. With the continual pushing for higher levels of cross bend, OE auto glass manufacturers face a number of challenges.

The Challenges
For example, among these challenges lies surface control. Wiper manufacturers have found that a 37-mm cross bend is the current limit of windshield wipeability. Another challenge lies with the optical qualities of the windshield. Simulations indicate that both transmission and secondary image optics for new high cross bend designs reach their clarity limits at approximately at 38 to 47 mm. 
Other challenges revolve around the bending of sidelites, wherein shape requirements become tough, in order to ensure that the glass slides smoothly into the doorframe slots. 

In the past, many of our techniques for producing bends have revolved around gravity and press technology. OE auto glass manufacturers have been hard at work to create new, advanced press-bending systems to meet the growing demand. This means that not only is the demand growing for complexity in glass shapes, but windshields also are becoming harder to make. Most industry experts agree that the demand for more bend level in the near future could double that of current bend limits.

Coatings
Another exciting area of current development has revolved around hydrophobic and hydrophilic self-cleaning glass coatings. Imagine never again needing windshield wipers or a defogger. It would be nice, but there are still some hurdles in these two areas of application. Hydrophobic coatings are coatings that repel water; among these are Aquacontrol™, Rain X™ and Aquapel.™

A couple of main reasons OE manufacturers have not utilized this 
technology totally is because, while the performance levels of these products are good, their durability level has usually been limited to several months at the most. In order to increase the performance and durability levels of these coatings, a certain level of roughness to the surface area is needed on the glass. The problem is that this leads to poor optical quality.

Hydrophilic self-cleaning coatings are those that are photocatalytically active. As you may recall, Pilkington unveiled Pilkington Activ™ glass, which has such a coating, in 2001. The coating allows the glass to clean itself by using ultraviolet light to break down and dissolve inorganic dirt through a photocatalytic effect. Due to its hydrophilic properties, this coating also causes the water to sheet down the glass and wash away inorganic dirt.

Many may wonder why we haven’t yet utilized these coatings on auto glass, but in auto glass applications there are some issues, such as sheeting tendencies of the water as it spreads over the glass and a subtle color tint on the glass as a result of applied 
coatings. 

Yet, while technical challenges still remain for hydrophilic and hydrophobic auto glass coatings, the future certainly looks bright for their application in the auto glass industry. They not only promise aesthetic value, but inherent traffic safety ramifications also. Our company is producing hydrophobic auto glass currently for select applications in the OE 
market.

Looking to the Future
These are but a couple of examples of the evolution of auto glass designs. You can rest assured there are other emerging trends, such as lightweight glazing that increases fuel efficiency, and multi-layer PVB for noise reduction. 

Additionally, a multitude of electronic attachments for navigation and communications are emerging continually, as are solar control advancements, solar control privacy glass advancements and the growth in laminated sidelite OE automotive designs for safety and anti-theft purposes. 

So if you ever hear the phrase, “Glass is glass and it’s all the same,” there are many reasons to disagree. The research and development levels that are employed by OE manufacturers are profound, and the burdens of safety requirements placed on glazing materials are impressive. This should be reason enough for all of us to take the time to educate consumers, selling them on the importance of quality. 


Jason Wright is the technical services manager for Pilkington North America. He is based in Columbus, Ohio.

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