 What is Perforating? |
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Perforating Definition
Perforation refers to the puncturing of a material with a harder (usually sharp) object to create a hole or opening.
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Methods of perforation
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Pins and needles
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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.
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Cold needle perforation can cause a "volcanic cone" shaped structure in the material, which can be beneficial for a number of applications. Cold perforation tools include needle punches.
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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.
For microperforation, pinned rollers can be made from a variety 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. |
Die and punch |
| 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. Other examples include hole punching and ticket punching. Punches can be designed for a desired hole shape. |
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Laser perforation |
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Laser perforation can place many precise holes in a web. Laser perforations look similar in many respects to hot needle perforations. However, laser systems can be expensive to purchase and maintain. Many use an array of mirrors to direct the beam of light. |
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Process Characteristics
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- A variety of shapes and number of holes desired can be produced using this mechanical reducing process.
- Punch and die clearance controls the quality of the hole.
- The material to be punched out is sheared from the workpeice when the punch pierces it and enters the die.
- Burrs are produced on the side of the workpeice that is against the die.
- Holes are punched in desired patterns.
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Process Schematic
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Usually there are a number of punches and dies in a given set. The clearance(the measured distance between the outside circumference of the punch and the inner circumference of the die) must be maintained to ensure a clean cut from the workpeice. The punch is pressed through the material(either by machine or hand tool) and into the die removing a blank, or chad, resulting in a perforated workpeice.
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Process Purposes
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There are a many different purposes for perforating a workpeice including:
- Filtration of fluids
Enhancing sound deadening
- Allowing light, liquid, air, or gas through a material
- Creating holes to embed something into the workpeice
- To create an aesthetic design in a panel of material
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Setup and Equipment
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Perforating can be done either manually or by machine, such as a hydraulic-press. In both types, the punches and dies are arranged in a precisely measured design for the desired result.
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| Photochemical Etching |
Photochemical etching is an ideal process for grids, screens, meshes, filters, separators and other perforated metal applications.
The etching process produces consistent, burr-free holes as small as .004” in .002” thick material. As a general rule, minimum hole size is 110% of the thickness of the material, e.g. on .010” material, the smallest hole would be .011.”
Unlike mechanical perforating methods such as punching, stamping or laser cutting, photochemical machining leaves the material free of burrs and induced mechanical or thermal stress or deformation.
Applications range from heavy gauge effluent filtration to extremely fine thin-gauge filters and diaphragms for liquids and gases.
Metal meshes can be photo etched in a wide variety of alloys including steel, nickel, copper, brass, aluminum and more. Holes can be made in a variety of shapes and sizes at no additional cost in tooling.
Photo etched meshes, grids, filters and screens are used in many types of industrial applications. In many cases, chemical etching of metal meshes provide better value and performance than woven or punched products. |
Reference: Todd, Robert H.; Allen, Dell K.;(1994). Manufacturing Processes Reference Guide. New York: Industrial Press Inc. Pg.103-104 |
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