Here's how zippers are made from start to finish

Let's pay a visit to a zipper factory!

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Chances are you probably use a zipper at least once every day of your life. From jackets to pencil cases, zippers are absolutely everywhere in our modern world.

While you probably never give them a second thought until they break or jam, the process behind making them is actually quite interesting. To this end, let's take a little tour of one factory that makes zippers from start to finish. 

making a zipper complete
Source: Interesting Engineering

Step 1: Melt the metal

The first step is to source the right metal for the zipper. Typically zippers will be made of either aluminum, chrome, or brass or, as in this case, a special alloy of metals that is strong enough to be used for the task.

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For these particular zippers, a special alloy called ZAMAK is used. This is an alloy of a base of zinc and alloying elements of aluminummagnesium, and copper. The name itself is a portmanteau of the names of the metals that make it, i.e. Zinc, Aluminum, MAgnesium, and Copper. 

making zippers metal
Source: Interesting Engineering

Once the ingots of ZAMAC are delivered to the factory, these are unpacked and prepared to be melted down ready to make the zippers. Once molten, the ZAMAC is poured into some molds to form larger ingots ready for the next phase of manufacture. 

Step 2: The zippers are pressed

Once in this larger form, the ingots are then melted down again and fed into another special machine. This machine melts down the ingots and then feeds the melt to a special hydraulic press.

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This press compresses the metal against a mold to form the main parts of the zipper in small batches that are then fed via a series of chutes into a storage bin.

Other molds are used to press out the main zipper slider and pull parts. 

making a zipper teeth
Source: Interesting Engineering

With that done, the zipper piece sprues are then fed into a special spinning machine that breaks up the sprues into their individual parts. Other parts, like the slider and pull, are also released from their sprues using a similar process. 

Once isolated all parts of the zipper are fed along with special vibrating conveyor belts and sprayed with water to clean off any dust and debris from the molding process. When the cleaning process is complete, the parts are then fed into another storage bin ready for the next phase of manufacture. 

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Step 3: The zipper is assembled

With the main parts of the zipper now complete, the next step is to actually put all the pieces together. To this end, the parts are fed into the assembly machine in small batches. 

These are fed into a special vibrating and rotating hopper that feeds the parts into a specially designed conveyor system one at a time. 

zipper making teeth
Source: Interesting Engineering

While this is happening, another machine takes the individual sliders in a similar fashion. These sliders are fed to another pressing head that combines the main slider body with the top pull rings. 

Complete pieces are then dispensed and stored in another storage hopper. 

making zippers sliders
Source: Interesting Engineering

This process is entirely automated and is able to make a single slider in a matter of seconds. With that done, the zipper sliders are then fed into another part of the machine that takes them one at a time and attaches the zipper pull into place within the top rings of the slider. 

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As before, this is all completed automated and takes only a few seconds to complete. 

making zippers pulls
Source: Interesting Engineering

The process is fascinating to watch and happens almost too quickly for you to really see what is going on. 

With that complete, batches of zippers are bagged up ready for the next step in the process. 

Step 4: Completing the zipper

With the main zipper slides now complete, the last step is to take a series of plastic teeth strips and attach the zipper. These can either be provided to customers are premade strips of zippers, or, as in this case, can be sewn into place on some items of clothing. 

Once done, each zipper is then quality checked to ensure that it works as intended. If not, zippers are rejected and sent to be recycled by melting them down once again. 

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And with that, the process is now basically complete. 

If you enjoyed watching how zippers are made in a factory, you might be interested in watching another industrial process from start to finish? How about, for example, watching how cymbals are made by hand? 

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