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Perforation refers to the puncturing of a material with a harder (usually sharp) object to create a hole or aperture. Peforation or microperforation can be created by pins, needles, die and punch or laser. Rotary pinned perforation rollers are precision tools that can be used to perforate a wide variety of materials. The pins / needles can be used cold or heated. Cold perforating can cause a volcanic structure in the material, which can be beneficial for a number of applications. Hot needle perforation melts the material being perforated, and creates a reinforcing ring around the hole. This can also be beneficial in many applications, as the ring assists in keeping the integrity of the material. There are a handful of manufacturers that specialize in hot and cold needle perforation tooling and equipment. Pinned rollers can be made from a veriety of materials to include plastic, steel, aluminum, or other materials. Pinned sleeves can be slid onto a central shaft, so that pin patterns may be interchanged at will. There are very few manufacturers in the world that make this precision tooling. Stewarts of America, Inc. in Simpsonville, South Carolina USA would be an example [1]
Die and punch sets can be used for thicker materials, or materials that require large gauge holes. The material is sheared by the sharp edges of the punch and die, and the chad is removed. One will see punched perforations in fruit produce bags.
Laser perforation can place many precise holes in a web. Laser perforations look similar in many respects to hot needle perforations. However there is a price to pay for a laser system. They can be expensive to purchase and maintain. Many use an array of mirrors to direct the beam of light.
One of the most common perforations are found in stamps.
A perforation is a hole made by puncturing a surface. However, the term frequently refers to the practice of creating a long series of holes so that paper can be torn more easily along a given line. Postage stamps are one common application of this, where small round holes are cut in lines to create individual pieces (see postage stamp separation). Since the creation of perforation devices in the 1840s and 1850s, it has seen use in several areas. It is common for notebooks and legal pads to have perforations making it easier to tear out individual pages. Perforations on stamps are rather large, on the order of a millimeter, in comparison other perforated materials often have smaller holes. Film stock is perforated to allow it to be moved precise distances at a time continuously. Screwcaps on glass or plastic bottles are sealed with a ring at the bottom of the cap attached by perforation. Twisting the cap has the effect of rupturing the perforation and indicating that the original seal has been broken.
In today's cases, perforation is used in ways to separate loose leaf (or even a form of graph paper from a ringed binder). A fine perforation next to the rings allows the page to be separated from the book with no confetti.
See also
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- This page was last modified on 25 August 2008, at 15:26.
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