Zippers can be found on clothing on bags even on foot where the zipper started out as a newfangled closure mechanism for boots and tobacco pouches. The fashion industry didn’t put them on clothing until the nineteen thirties. Some 80 years after the invention of this fabulous fastener an American alliance how was the first to patent azipper like clothing fastener in 1851 but he never ended up marketing it. It wasn’t until 1893 that another American Whitcomb Johnson designed a similar device called a class blocker he eventually hired a Canadian engineerGideon Sundback to simplify the original complex design which had never really taken off in 1917 Judson and son back patented the modern zipper.
Zipper teeth are made of either metal plastic or nylon the fabric part of the zipper is called the tape is usuallypolyester but sometimes cotton or a fireproof fabric to make metal zippers. From the factory feeds a long continuous roll of tape into what’s called the teeth machine along with a long roll of metal ribbon known as flat wire. The Machine cuts off a tiny piece of flat wire forces it through a dye that forms it into a to shape then clamps it onto the edge of one side of the tape. The Machine does all this at a rate of 45 teeth per
second. These zipper teeth are aluminum sturdier zippers are made of stronger metals such as brass and nickel depending on the model teeth can range in with from about 3 to 10 millimeters. The wider the teeth the thicker they have to be workers now feed two tapes with metal teeth into what’s called the joining machine the
teeth interlock meshing the two halves of what’s now a continuous zipper from there it’s into a cleaning machine which first washes. The zipper removing any shards of metal left behind by the tooth cutting process after drying the zipper the machine applies a coat of hot wax. This lubricates the teeth so the slider will glide over them smoothly.
Next stop is the gapping machine it removes a 4 centimeter long section of teeth at regular intervals they later cut the tape at these gaps dividing the continuous zipper into several shorter zippers there are two main types ofzippers closed and zippers of a kind whose two halves don’t separate at the bottom when opened cursed zippers for example these need a part called a bottom stop a thick piece of flat wire positioned at the case of the zipper when you unzip it stops the slider and prevents. To have some separating open and zippers are the kind who’s two halves do separate at the bottom when opened jacket zippers for instance at the bottom of these zippers a machineapplies a clear reinforcements trip this stiffens the tape so that the next machine can apply the pin and box.
The pin is that vertical piece of metal of one half of the zipper that you have to align in the Box on the other halfbefore you can pull the slider to zip up the next machine installs the slider watching slow motion as it opens each gap and hooks a slider onto the track of teeth. The next machine inserts what’s called the top stop a thick piece of flat wire that stops the slider at the top of the track when you zip up all the way the machine then slices the tape at each gap separating the finished zippers.
Plastic zippers are made quite differently than metal ones the tape is the same but the teeth are made from plastic pellets a machine melts them then injects the liquid plastic into a mold that’s the shape of a strip of zipper teeth. The mold cools almost instantly hardening the plastic. The machine then stamps the teeth on to the tape automatically gapping the desired super length at the same time the excess plastic in the middle is remelted. There’s no joining machine to mesh the two halves of plastic zippers workers do this manually so that they can inspect the plastic teeth to make sure they’re well formed an automated machines install the remaining components.