Posted on: October 1st, 2020
After the seat belt and the braking system, the most important part of the car to keep you safe is the windshield. It prevents you from getting hit in the eyes by any particle or small object at high speed. It also protects you from rain, snow, or any other weather changes. What are the windshields or windscreens made of? Can we rely on any material? If it breaks, how can we trust in this window to not to hurt us? What makes this kind of window different from any other? You will find those answers further in this article.
Back in the days, the first cars used normal glass to avoid the wind burst to reach the driver’s eyes. At low speeds, it was not deadly, but after some incidents, conventional glass was replaced for tempered glass (also known as toughened glass). Tempered glass reduced the injuries made from your windshield considerably, but the best choice for a good windshield is laminated glass.
Let us talk about materials, due there is not much to say about it. Most car glasses are made of the same materials which are: silica sand (SiO2), dolomite ((CaMg)(CO3)2), soda ash (Na2CO3), limestone (CaCO3) and a few parts of cullet glass (recycled glass mostly). Some glasses have a small part of potassium oxide and aluminum oxide.
In the case of laminated glass, security gives a step ahead by adding a film of polyvinyl butyral (PVB), Thermoplastic Polyurethane (TPU), or ethylene-vinyl acetate (EVA). This film helps to prevent the windscreen from letting the shattered glass to fall in your face by holding the pieces as close as possible. There you will see a chip or a hole in your windshield surrounded by some sort of spiderweb-like cracks.
More advanced technologies allow your car to have computer screens on them to let you change some features of your car, have a connection with other devices, or even have features for augmented reality. These windshields have other kinds of components like graphene or any superconductor to turn your windows into a part of your smart car.
From 3.600 BC, pieces of glass appeared in some areas of Egypt and Mesopotamia. They were made of sand and were used to decorate some temples or pharaoh houses. Later, it is said that glass was added to chariots in England about the first century A.D. But it would not be until the invention of the automobile that glass was used as the conventional windshield in 1904. Then, after some trial and error, engineers started to research and experiment to get the perfect safe windshield for the front window of any car. Materials, techniques, and shapes were proved to achieve this goal.
Depending on the kind of glass you choose to have in front of you, materials may vary. It is recommended obviously to have laminated glass, but some people still try to save a few dollars by having a windshield replacement using tempered glass. Now let us see how each one is made.
Let us talk about the laminated glass. It is made by cutting the glasses in any desired windshield size (the outside lamina and the inside lamina). After cutting, the glass is heated in order to make it easier to bend according to the model of the windscreen. Then the makers start the process of attaching one to the next one by placing a film of PVB, TPU, or EVA (plastic or vinyl films). This vinylic film is in charge of grabbing the shattered pieces in case of a break.
Laminated glass is highly resistant speaking of the car’s structure. It can hold practically the entire weight of the car in case of overturning, which helps you to be safe in the worst-case scenario. Laminated glass is so resistant that in case of a car crash it prevents the body from flying away from the cabin, which lowers the damage taken by the passengers considerably.
In the case of tempered glass, the process is simple having on consideration the machinery to make it. The glass goes through a process of heat treatment to ensure it reaches a specific temperature and then the technicians let the glass’ temperature drop. This way they make sure the glass will break into small harmless pieces, so if it breaks do not cut the passengers nor the driver. Making this kind of glass is a lot cheaper than the laminated glass, but for obvious reasons, you should not have it in the main front glass. Additionally, in most of the states across the country, according to the law, you should not have it on your windshield made of other glass than the laminated one.
Laminated glass has a quality control process where the glass is tested by wind, sand, water, pressure, and shock. The most iconic test is maybe the one where a windshield is set on a base beneath an apparatus in which a metal ball is placed 4 meters or more and then is dropped on the windshield. This test is done to figure out if the auto glass is resistant, and to see how resistant it is.
This last test cannot be passed by a windshield made of tempered or toughened glass. Hence, the general recommendation is leaving the tempered glass for doors and only laminated glass for the windshield.
Every auto glass factory has to measure strictly the main ingredients that compound the windscreen, from the silicates to the cullet. After gathering and weighing in proportions, all the ingredients go to a mixer. Everything is mixed with a small part of water to avoid the segregation of the raw materials. Later, all go to a tank where the batch goes through a process called “float glass”.
This process lets all materials in the batch reach the molten state before it goes to another tank called the “float chamber”. Here, the batch receives a bath of molten tin. As the tin does not mix with the raw materials, the early glass starts to look flat. The tin must reach the thousand Celsius degrees for this, which is one thousand eight hundred thirty-five Fahrenheit degrees. All this work rolls upon a conveyor belt, going out from the float chamber without impurities or imperfections, flat and clear.
Once the glass gets hard enough (after cooling down out of the float chamber), it is ready to transport to the next part of the process. The resultant glass goes into another chamber called “Lehr” where the glass cools down from two hundred Celsius degrees (three hundred ninety-five Fahrenheit degrees) to room temperature. In the lehr, the manufacturer can apply any solar coating if he wants, not later, not before. Now the glass is ready to be cut.
The window is cut using a diamond scribe to mark the shape of the glass, and pressure to break it on the planned spots. Some factories can cut the glass using lasers. The whole cutting process is always monitored by sensors, cameras, and other measuring electronic systems. The cut pieces go to a machine where it is heated again until the point where the window can be shaped by bending it into a mold.
The process is almost finished. Right here, the glass must be tempered using heat to make it reach more than eight hundred fifty Celsius degrees (a thousand and six hundred Fahrenheit degrees), and then the glass gets showered with bursts of cool air to cause microfractures. It is done to prevent the shattering pieces of the window from having cutting edges.
After cleaning the tempered pieces, the glass is ready to get the lamination treatment. In this stage, two layers of glass are placed on each side of a film made of plastic material. Then it goes to a special oven where the plastic gets hot while presses keep the pieces aligned. In most cases, the plastic is tinted to give the windshield some UV protection. Finally, after setting up the window in a plastic mold, the windshield is ready to transport or to install.
The main advantage of having a laminated glass is a matter of safety. But if a chip appears on the windshield, you can fix it instead of getting the whole piece replaced.
On average, the manufacturing cost of a basic windshield is under one hundred and fifty dollars. The cost tends to rise if the windshield has special features like any of the following:
Practically any new technology added on the window can raise its cost, but the value of every feat pays itself. On the other hand, let us talk about the two qualities available to find a manufactured windshield. Basically, there are two: Original Equipment Manufacturer (OEM) and Aftermarket Quality.
In the first (the OEM), quality usually exceeds the original windshield that came with the car. A window made by OEM is mostly made to fulfill a need for something beyond a mere windshield. This kind of product, therefore, has a larger warranty than others.
Now, the Aftermarket Quality windshields are average in both price and quality. In the worst-case scenario, the windscreen must just meet the minimum standards set by the Department Of Transportation (also known as DOT) of the USA. Aftermarket windshields are cheaper than the other, but it does not mean it will be a glass scam. Both kinds of windows are manufactured by serious factories and not by some John Doe in some random alley. If you want to save money, it is recommended to buy the Aftermarket windshield. The decision is yours.
A windshield properly manufactured should be able to pay the cost of machinery usage, raw material prices, real estate costs for the factory, and transportation costs. Therefore, depending on the brand, size, extra features, and the demand, the costs of making a windshield may vary.
Here, in the land of the free and the home of the brave, we have factories in many states. Throughout Michigan, Ohio, Kentucky, and Indiana, there are a lot of factories of companies like AGC Glass Company North America, PGW Glass Pilkington North America, and Guardian Industries. These companies have some headquarters in Canada and Mexico, so if you want to compare prices, you can call and compare.
But not all industries are American. China has two major companies making auto glass for American people, on American soil. Fuyao Glass America and Xinyi Glass are the two top companies making auto glass with several facilities alongside Ohio, Michigan Illinois, and South Carolina giving jobs to American people. Likewise, the Mexican company Vitro has facilities in the USA producing high-quality auto glass.
On the other hand, if you are looking for an auto glass of some European, or Asian brand, you better call the offices and dig into information. Brands like Daewoo, Mitsubishi, Audi, Ferrari, or any other foreign brand, depends on the dealer. You better be patient if your car’s windshield is not easy to find.
Other companies for you to know are Asahi Glass Co, Splintex distribution, Nippon Sheet Glass, Olimpia Auto Glass, Pittsburgh Plate Glass Company (PPG), Sekurit Saint-Gobain, Shatterprufe, Soliver, Star Glass, Tamglass, and many others. So you might never run out of places to get your auto glass made.
Now that you know how the windshield is made, you can feel safer inside your car. The auto glass has a history that can be traced back to ancient Egypt because there is the first known glass ever made. Later, used on chariots, and finally on cars. Nevertheless, the auto glass has evolved in the last hundred years to provide safety and comfort for you and your family. Remember all this next time you see the rain sliding down your window.
