How is Bulletproof Clothing Made?

How is Bulletproof Clothing Made?

How does bulletproof clothing work?

"All that changed with the development of cannons and guns in the 1500s. These weapons hurl projectiles at a high rate of speed, giving them enough energy to penetrate thin layers of metal. You can increase the thickness of traditional armor materials, but they soon become too cumbersome ­and heavy for a person to wear. It wasn't until the 1960s that engineers developed a reliable bullet-resistant armor that a person could wear comfortably. Unlike traditional armor, this soft body armor is not made out of pieces of metal; it is formed from advanced woven fibers that can be sewn into vests and other soft clothing.

Hard body armor, made out of thick ceramic or metal plates, functions basically the same way as the iron suits worn by medieval knights: It is hard enough that a bullet or other weapon is deflected. That is, the armor material pushes out on the bullet with the same force (or nearly the same force) with which the bullet pushes in, so the armor is not penetrated.

Typically, hard body armor offers more protection than soft body armor, but it is much more cumbersome. Police officers and military personnel may wear this sort of protection when there is high risk of attack, but for everyday use they generally wear soft body armor, flexible protection that you wear like an ordinary shirt or jacket. Soft body armor is a fairly mystifying concept: How can a soft piece of clothing stop bullets? The principle at work is actually quite simple. At its heart, a piece of bullet-proof material is just a very strong net.

To see how this works, think of a soccer goal. The back of the goal consists of a net formed by many long lengths of tether, interlaced with each other and fastened to the goal frame. When you kick the soccer ball into the goal, the ball has a certain amount of energy, in the form of forward inertia. When the ball hits the net, it pushes back on the tether lines at that particular point. Each tether extends from one side of the frame to the other, dispersing the energy from the point of impact over a wide area.

The energy is further dispersed because the tethers are interlaced. When the ball pushes on a horizontal length of tether, that tether pulls on every interlaced vertical tether. These tethers in turn pull on all the connected horizontal tethers. In this way, the whole networks to absorb the ball's inertial energy, no matter where the ball hits."



Bulletproof clothing protects you because the bullet bounces off of the material. The material used catches the bullet and then it bounces off of the vest. Hard body armor is made of metal and soft armor is made of material. Hard body armor offers more protection than soft body armor (Harris).

Commentary

I think it's interesting that bulletproof vests have that kind of reflex against the bullet. I always thought that the bullet would sink into the vest and not get a chance to injure the person because of the thickness of the vest. I like the comparison between the ball hitting a soccer net and the bullet hitting the bulletproof vest. It gave me a visual of what was happening.

What is bulletproof clothing made of?

"The Manufacturing

Process

Some bulletproof vests are custom-made to meet the customer's protection needs or size. Most, however, meet standard protection regulations, have standard clothing industry sizes (such as 38 long, 32 short), and are sold in quantity.

Making the panel cloth

1 To make Kevlar, the polymer poly-para-phenylene terephthalamide must first be produced in the laboratory. This is done through a process known as polymerization, which involves combining molecules into long chains. The resultant crystalline liquid with polymers in the shape of rods is then extruded through a spinneret (a small metal plate full of tiny holes that looks like a shower head) to form Kevlar yarn. The Kevlar fiber then passes through a cooling bath to help it harden. After being sprayed with water, the synthetic fiber is wound onto rolls. The Kevlar manufacturer then typically sends the fiber to throwsters, who twist the yarn to make it suitable for weaving. To make Kevlar cloth, the yarns are woven in the simplest pattern, plain or tabby weave, which is merely the over and under pattern of threads that interlace alternatively.

2 Unlike Kevlar, the Spectra used in bulletproof vests is usually not woven. Instead, the strong polyethylene polymer filaments are spun into fibers that are then laid parallel to each other. Resin is used to coat the fibers, sealing them together to form a sheet of Spectra cloth. Two sheets of this cloth are then placed at right angles to one another and again bonded, forming a nonwoven fabric that is next sandwiched between two sheets of polyethylene film. The vest shape can then be cut from the material.

Cutting the panels

3 Kevlar cloth is sent in large rolls to the bulletproof vest manufacturer. The fabric is first unrolled onto a cutting table that must be long enough to allow several panels to be cut out at a time; sometimes it can be as

Kevlar has long been the most widely used material in bulletproof vests. To make Kevlar, the polymer solution is first produced. The resulting liquid is then extruded from a spinneret, cooled with water, stretched on rollers, and wound into cloth. A recent competitor to Kevlar is Spectra Shield. Unlike Kevlar, Spectra Shield is not woven but rather spun into fibers that are then laid parallel to each other. The fibers are coated with resin and layered to form the cloth.

Kevlar has long been the most widely used material in bulletproof vests. To make Kevlar, the polymer solution is first produced. The resulting liquid is then extruded from a spinneret, cooled with water, stretched on rollers, and wound into cloth.

A recent competitor to Kevlar is Spectra Shield. Unlike Kevlar, Spectra Shield is not woven but rather spun into fibers that are then laid parallel to each other. The fibers are coated with resin and layered to form the cloth.

long as 32.79 yards (30 meters). As many layers of the material as needed (as few as eight layers, or as many as 25, depending on the level of protection desired) are laid out on the cutting table.

4 A cut sheet, similar to pattern pieces used for home sewing, is then placed on the layers of cloth. For maximum use of the material, some manufacturers use computer graphics systems to determine the optimal placement of the cut sheets.

5 Using a hand-held machine that performs like a jigsaw except that instead of a cutting wire it has a 5.91-inch (15-centimeter) cutting wheel similar to that on the end of a pizza cutter, a worker cuts around the cut sheets to form panels, which are then placed in precise stacks.

Sewing the panels

6 While Spectra Shield generally does not require sewing, as its panels are usually just cut and stacked in layers that go into tight fitting pouches in the vest, a bulletproof vest made from Kevlar can be either quilt-stitched or box-stitched. Quilt-stitching forms small diamonds of cloth separated by stitching, whereas box stitching forms a large single box in the middle of the vest. Quilt-stitching is more labor intensive and difficult, and it provides a stiff panel that is hard to shift away from vulnerable areas. Box-stitching, on the other hand, is fast and easy and allows the free movement of the vest.

7 To sew the layers together, workers place a stencil on top of the layers and rub chalk on the exposed areas of the panel,

After the cloth is made, it must be cut into the proper pattern pieces. These pieces are then sewn together with accessories (such as straps) to form the finished vest.

After the cloth is made, it must be cut into the proper pattern pieces. These pieces are then sewn together with accessories (such as straps) to form the finished vest.

making a dotted line on the cloth. A sewer then stitches the layers together, following the pattern made by the chalk. Next, a size label is sewn onto the panel.

Finishing the vest

8 The shells for the panels are sewn together in the same factory using standard industrial sewing machines and standard sewing practices. The panels are then slipped inside the shells, and the accessories—such as the straps—are sewn on. The finished bulletproof vest is boxed and shipped to the customer."



Bulletproof vests are made of a tight fabric. The fabric used has threads that are weaved together tightly so the bullet can't easily go through. Most of the materiel used is specially made to fit the person's needs ("How Products Are Made").

Commentary

Making the vest can be a difficult process. You have to make everything the same exact size that fits the person. The materials can be hard to make. I like how the author of this article included everything step by step on how to make the vest so the reader know how to create the vest. I think it's interesting that the bullet wouldn't break thought the tight fabric.

Works Cited

Harris, Tom. HowStuffWorks. HowStuffWorks.com, n.d. Web. 19 May 2015.


"How Products Are Made." How Bulletproof Vest Is Made. N.p., n.d. Web. 22 May 2015.