About Auto Glass:

The windshield or windscreen of an aircraft, automobile, bus, motorcycle, or tram is the front window. Modern windshields are generally made of laminated safety glass, a type of treated glass, which consists of two (typically) curved sheets of glass with a plastic layer laminated between them for safety, and are glued into the window frame.

Motorcycle windshields are often made of high-impact acrylic plastic. As the name implies, their main function is to shield the driver from the wind, though they do not do so as totally as those of a car, whereas on sports and racing motorcycles the main function is improving the drag coefficient when the rider assumes the most aerodynamic optimal configuration of his body in unison with the machine and does not shield the rider from wind when sitting upright.

First, a sheet of glass is scored by an automated plotter. Then a robotic arm completes the cut with a propane torch.

Sanding belts take off the sharp edges in an operation called seaming. In the Manufacturing Processes Reference Guide, this operation is referred to as band filing, which is “a multipoint cutting process in which a workpiece is fed into a continuously moving file, and chips are removed by cutting teeth that are arranged in succession along the file surface.” Sandpaper, used in this process, is a type of file that has an abrasive materials pasted onto primarily cloth backings.

Following the seaming, the glass is then washed in water and then sprayed with talcum powder to prevent glass sheets from sticking to each other. Next, another glass sheet is placed on top of the first sheet. A silkscreen is painted around the glass which will show where the frame for the vehicle will be relative to the windshield.

The samples are inspected visually, and then transferred to rollers to align the two glass sheets together. The glass is then put onto four pins, which recede, leaving the glass on a bending iron so it can be formed into a specific shape of windshield. A conveyor takes the sheets to a bending leer, a type of oven that heats the glass and allows the glass to fit the shape of the bending iron. Following that, the glass goes through a slow cooling process to strengthen the glass.

To laminate the glass, a sheet of milky white vinyl is placed between the two sheets of glass. The windshield then is transferred to a nipper, where rubber rollers press the pieces of glass together, pushing out any air bubbles in the vinyl. This allows the windshield to become transparent once again. The windshield is then put into a pressure cooker where the remaining air bubbles are removed. After that, the windshields are inspected by a human.

A sample windshield is taken and a 2.25kg steel ball, representing a driver’s head, is dropped from 4 meters above the windshield to test the quality of the windshield. If the ball hits the glass, but doesn’t travel through the glass, the safety test is successful.

The windshields are then examined for stress defects by viewing the windshield through polarized light. Once it has been determined that the windshield is road ready, the windshields can be put into the various vehicles that require them.