You may not know that your windshield is actually there for your safety more than to keep out the bugs. That laminated glass saves countless people from death and serious injury every day during automobile accidents.
Laminated glass has many uses, but is most important to the auto industry. Drivers around the world reap the benefits of laminated glass each time an auto accident occurs. Protected behind the triple layer glass, drivers and passengers avoid dangerous debris. It also blocks all but 5% of the dangerous UV rays from the sun. The advent of laminated glass transformed the making of automobiles, ushering in an era of the auto industry being dedicated to the safety of its passengers.
Made of three layers, laminated glass is constructed from a very thin layer of substrate sandwiched between two pieces of glass. Each separate piece of glass is completely cleaned before being adhered to the substrate. This step is extremely important, as the integrity of the final piece of laminated glass can be compromised if dust particles or other debris interferes with the adhesion process. On a more practical level, dust or debris would mar the final appearance of the glass while subsequently lowering the visibility of the driver.
In the beginning, laminated glass was created using cellulose compounds to form the substrate. These were the most common in production, but were eventually abandoned due to their propensity to darken after prolonged sun exposure. This was certainly not a desired trait in the final product. Modern windshields are created using a Polyvinyl Butyral substrate, known in the industry as PVB. Polyurethan and Ethylene Vinyl (EVA) are also used, but are not as common. Due to the additional hardening processes during manufacturing involving UV protection or additional chemicals, liquid substrates have not gained popularity.
A climate controlled environment in addition to the clean, uncompromised glass surface is critical for the adhesion of laminated glass. Because the substrate is applied manually to the initial sheet of glass, it is important that humidity and temperature are closely controlled at all times during the fabrication process to maintain the quality and functionality of the final laminated glass product. Laminated glass comes in varying layers, but automobile glass requires only one layer. After the first layer of substrate is applied, the second sheet of glass is simply arranged on top, sealing the substrate layer. Excess substrate is trimmed and the process moves to the next stage.
After successfully combining the layers, all air trapped between them needs to be removed. This is done by heating and repeatedly rolling the glass, which releases any air trapped during adhesion of the substrate. The air gradually moves to the edges during the heating and rolling. This process continues until all of the trapped air is removed.
The next step requires the laminated glass to be placed in an autoclave. The autoclave heats the triple-layer glass to extremely high temperatures which further bonds the substrate and adds structural strength to the final product. It remains in the autoclave for several hours. Any excess substrate receives a final trim when it is removed from the autoclave. The last step in the process: shipping the laminated windshield to various car manufacturers around the world.
The next time you go for a drive, take a minute to appreciate your windshield and the process that made it your car's first line of defense!
Tempered Glass
Tempered glass is used far more extensively than most people realize. Did you know that every window in your car (except for the windshield) is made of tempered glass?
Tempered Glass Production
Tempered glass, used primarily in cars and buildings, is up to six times stronger than regular glass. Tempered glass is reduced to small pebbles of glass when broken, which is much safer than the breaking pattern of regular glass and which gave tempered glass it’s more popular name - Safety Glass.
The Wonder Of Laminated Glass
When normal glass breaks, it often shatters into dangerous splinters and shards. The broken glass can easily cut, maim, or even kill a human being. Laminated glass is the solution for the windshield of your vehicle. Although it may shatter, the many small pieces of the windshield we be relatively harmless.
