Here's how double glazing units are made in a factory

Once in place, the glass sheets are fed into the main glass processing machines ready for cutting. Glass sheets are fed through a series of conveyor belts and rollers until in place at the right cutting head. 

Depending on the design of the window panes in question, a large cutting blade, similar to a paper guillotine, runs back and forth across the surface of the glass sheet, scoring the panes in one smooth and automated process. 

Shortly after, special light sensors are shone through the glass sheets to check that their quality and optical properties meet the factory exacting standards. Once satisfied, the machine moves the scored glass sheets on to the next stage of production via a conveyor belt. 

Step 2: Making the panes

The next stage in the process takes the scored glass sheets and separates them into individual small glass sections. This is done by hand by a skilled workman who gently bends and flexes the glass sheets to split them safely and cleanly. 

The process takes a great level of care and skill, else the glass sheets completely shatter. While workers are usually very experienced, and accidents are rare, they wear appropriate safety gear just in case. 

The newly created glass panes are stacked and stored ready for the next part of the process. Where needed, the panes are secured in place using restraints to prevent them from accidentally slipping, falling, or otherwise breaking. 

Step 3: Cleaning the glass

The next step is to add features required for the final window panes as needed. In this case, a series of holes are required in the piece, so a special water-lubricated and cooled drill is used to cleanly and safely sink some holes through the glass panes. 

Once complete, the next step is to give the glass a good, deep clean. A special carwash-like machine does this job. 

Glass panes are dragged through the cleaning machine on special soft rollers, all the while cleaning the surface of the glass as it goes. 

Any human workers involved in the process wear gloves to prevent them from accidentally touching and smudging the freshly cleaned glass. After a spot of drying, the glass panes are then ready for the next stage. 

The glass panes are then fed into another machine for tinting and coloring the glass if needed. Depending on the glazing type, the color and form of this tinting will vary widely. 

Once that is done, if needed, the glass panes are then fed out of the machine and are ready to be turned into windows. 

Step 4: Finish the windows

The next step is to make the other elements needed to make a window - the frame and grilles. These start out life as extruded lengths of metal that are cut down to size using special machines as needed. 

The length and type of metal used varies depending on the final design of the window. 

Following this, another round of quality checks is performed to check that the metal lengths are up to the factory's quality standards. Once ready, the pieces are shaped, bent, and formed into the size and shape of the frames needed for each piece of glass.

With the metal frames ready, the last thing to do is combine them with the glass panes. This is done with yet another machine that takes the glass panes on a special feed conveyor. The glass panes are then inserted into the metal frames by a skilled workman. 

If grilles are required as part of the design, these are also added inside the double glazing unit prior to being sealed. 

With the first pane in place, a machine then presses a second pane to the other side of the metal frame and seals the unit as needed. A layer of a putty seal is then run around the outside edge of each unit to make sure they are completely airtight.

And with that, the double glazing units are ready for shipping out. 

If you enjoyed this industrial process behind the scenes, you might enjoy another. How about, for example, watching how clothes are made from cotton?