The Manufacturing of Windshields
Your windshield is a rather genius invention. It is comprised of two pieces of glass, secured together by a film. Each sheet of glass is actually composed of silica, sodium oxide, and calcium oxide. These oxides are fused together during the heating process. As with all manufacturing processes, careful consideration is given to the weight and accurate composition of these oxides. Broken unusable glass, known as cullet, is also reused, to minimize waste.
Once the oxides have been measured, they are mixed with a little bit of water to prevent separation. The first batch of oxides are then fed into a tank for melting. It is moved through what is called a float chamber. There is molten tin in the float chamber, and the molten glass rests upon it, causing the glass to flatten. The heat also cleans the glass out, removing any impurities. It is slightly cooled, and moved into a furnace known as a lehr. Once it exits the lehr, being gradually cooled in the process, it is left out to drop down to room temperature.
Still in its large rectangular form, the glass needs to be cut. Diamond tools, known as scribes, are used to cut the dimensions of the glass into a windshield. Diamond is harder than glass, and this scribe is typically automated by a robot for accurate cutting. Once cut, the glass still needs to be bent. It is placed into a metal mold, and heated in another furnace until it conforms to the mold.
Once shaped, it is heated through another process called tempering. This process allows the windshield to break into many tiny pieces, reducing the likelihood of sharp edges. The glass is quickly heated to over 1500 degrees Fahrenheit, and then rapidly cooled with blasts of cold air. This process, called quenching, toughens the glass, causing the inner surface to be tense, and the outer surface to be compressed.
At this point, the glass goes through a laminating process. Two sheets of glass are bonded with a thin layer of plastic in between them in an oven that utilizes heat and pressure to prevent windshield tearing. The plastic is often UV coated, serving as a filter to ultraviolet light. If either individual glass sheet is ever broken, the pieces stick to this plastic layer, maintaining visibility and safety.
The windshield is now at its final step: assembly. Known as glass encapsulation, the windshield is assembled with plastic moldings. The glass is set in the mold, and molten plastic is injected into the mold, forming the frame around the glass. It is then shipped to car manufacturers and other distributors, so companies such as Fullerotn's Best Auto Glass Repair can affix it to the proper vehicles.
If you would like more information about the perfect windshield for your vehicle, please give us a call at 657-208-9093.