Today's
zippers comprise key components of either metal or plastic. Beyond this one
very important difference, the steps involved in producing the finished product
are essentially the same.
1). Making
stringers — metal zippers
A
stringer consists of the tape (or cloth) and teeth that make up one side of the
zipper. The oldest process for making the stringers for a metal zipper is that
process invented by Otto Sundback in 1923. A round wire is sent through a
rolling mill, shaping it into a Y-shape. This wire is then sliced to form a
tooth whose width is appropriate for the type of zipper desired. The tooth is
then put into a slot on a rotating turntable to be punched into the shape of a
scoop by a die. The turntable is rotated 90 degrees, and another tooth is fed
into the slot. After another 90 degrees turn, the first tooth is to make the
stringer for a spiral plastic zipper, a round plastic wire is notched and then
fed between two heated screws. These screws, one rotating clockwise, the other
counterclockwise, pull the plastic wire out to form loops. A head maker at the
front of each loop then forms it into a round knob. This method requires that a
left spiral and right spiral be made simultaneously on two separate machines so
that the chains will match up on a finished zipper clamped onto the cloth tape.
The tape must be raised slightly over twice the thickness of the scoop—the
cupped tooth—after clamping to allow room for the opposite tooth on the
completed zipper. A slow and tedious process, its popularity has waned.
Another
similar method originated in the 1940s. This entails a flattened strip of wire
passing between a heading punch and a pocket punch to form scoops. A blanking
punch cuts around the scoops to form a Y shape. The legs of the Y are then
clamped around the cloth tape. This method proved to be faster and more
effective than Sundback' s original.
Yet
another method, developed in the 1930s, uses molten metal to form teeth. A
mold, shaped like a chain of teeth, is clamped around the cloth tape. Molten
zinc under pressure is then injected into the mold. Water cools the mold, which
then releases the shaped teeth. Any residue is trimmed.
2). Making
stringers — plastic zippers
Plastic
zippers can be spiral, toothed, ladder, or woven directly into the fabric. Two
methods are used to make the stringers for a spiral plastic zipper. The first
involves notching a round plastic wire before feeding it between two heated
screws. These screws, one rotating clockwise, the other counter-clockwise, pull
the plastic wire out to form loops. A head maker at the front of each loop then
forms it into a round knob. Next, the plastic spiral is cooled with air. This
method requires that a left spiral and right spiral be made simultaneously on
two separate machines so that the chains will match up on a finished zipper.
The
second method for spiral plastic zippers makes both the left and right spiral
simultaneously on one machine. A piece of wire is looped twice between notches
on a rotating forming wheel. A pusher and head maker simultaneously press the
plastic wires firmly into the notches and form the heads. This process makes
two chains that are already linked together to be sewn onto two cloth tapes.
To
make the stringers for a toothed plastic zipper, a molding process is used that
is similar to the metal process described in step #2 above. A rotating wheel
has on its edge several small molds that are shaped like flattened teeth. Two
cords run through the molds to connect the finished teeth together. Semi-molten
plastic is fed into the mold, where it is held until it solidifies. A folding
machine bends the teeth into a U-shape that can be sewn onto a cloth tape.
The
stringers for a ladder plastic zipper are made by winding a plastic wire onto
alternating spools that protrude from the edge of a rotating forming wheel.
Strippers on each side lift the loops off the spools while a heading and
notching wheel simultaneously presses the loops into a U shape and forms heads
on the teeth, which are then sewn onto the cloth tape.
Superior
garment zippers can be made by weaving the plastic wire directly into the
cloth, using the same method as is used in cloth weaving. This method is not
common in the United States, but such zippers are frequently imported.
If
you want to know more about metal zipper and zipper puller, please contact with
UZIP ZIPPER.
Jessica
Kung
Skype:
tdysho
Wechat:
jessicakung1017
Whats:
8613631458295
