Perforated metals are metals that have been punched with holes or other shapes in a pattern or series. Used in building construction, interior and exterior design and many manufacturing applications like filters, strainers and piping inserts, perforated metal can be fabricated in a large number of configurations for use within the insulation, structural, filtration, food service, waste management and many other industries.
The number one application for perforated metals is as architectural perforated metals, which are used as decorations, access restriction utilities and in many other ways. Common perforated metals include perforated steel, perforated copper, perforated stainless steel and perforated aluminum, although perforated metal suppliers often manufacture a wide range of perforated alloys and specialty grades as well. Perforated brass sheets are just one example of the many alloy metals used to make perforated sheet metal products. Perforated metal panels are widely used in building construction and decoration, as are perforated metal screens. Many industrial and processing applications make use of perforated tubes, and thick perforated plates may be used in a variety of design or structural applications. Perforated sheet metal is made into screens, filters, baskets, trash cans, tubing, light fixtures, vents, audio speaker covers, patio furniture and many other products.There are two main manners of punching perforations into sheet metal, and they vary based on the complexity, repetitiveness and design of the hole patterns. For simple perforations, a standard punching press is used. As the sheet metal is slowly fed into the press, it is perforated by a large press containing the hole pattern. For decorative perforated metal panels that have complex designs using many different shapes in a non-repetitive manner, a sectional XY axis punching press, which is usually CNC controlled, is best in terms of accuracy and precision. Like the standard press, sheet metal is slowly fed through the punching press. It is secured to the machinery and moved around underneath one or several stationary punching rams with a single shape. As the sheet moves in the direction of the hole design, the rams create a detailed and complex pattern on the metal. This process takes much longer but produces complex and decorative perforated sheets and panels. The main advantages of CNC punching over manual punching are the lower labor costs associated with automation, the speed with which automated machinery can create products and the high repeatability of the process.
Types of hole patterns include staggered rounds, centers and squares, straight square slots, round and line squares, round slot end, side staggered, diamond, chain link, cross, hexagon and decorative cut outs like stars and flowers. Perforated metal manufacturers make their products out of stainless steel, galvanized steel, cold-rolled carbon steel, brass, copper, zinc, titanium, aluminum and other metals. Perforated sheets can be produced from sheets providing options that include margins and blank areas as well as with full perforation. Every perforation creates a piece of scrap metal, which generally can be recycled and made into more sheet metal. Since there are often so many perforations in the metal, perforated products are very light in weight, making them easy to handle and transport. A common way to produce perforated sheets begins with roll-formed coils. This method provides great flexibility in both design and handling. Perforated coils can be produced from coils as well, which is generally faster than perforating sheets.
Like perforated metals, expanded metals are also used for filtration, reinforcement and decoration. Expanded metals are similar to perforated metals, but they have been cut and stretched into a shaped framework rather than punched. Using expanded metal can be both cost-effective and ecologically sustainable, as the expanded metal fabrication process creates very little waste material and can expand a metal sheet's surface area by up to 70%. Applications for expanded metals are often similar to those of perforated metals; they include enclosures such as lockers and cages, supportive structures such as grating, shelves and catwalks, and protective structures such as guards and fencing. Although expanded metal is sometimes a cost-effective alternative to perforated metal, perforated metal is capable of being fabricated with much finer holes in a wide variety of configurations, making it an optimal choice for many metal screen applications as well as filter, design and construction applications. The decision whether to expand or perforate metal depends upon the industrial application, budget and specific design requirements. Perforated metal remains useful because it is easy to manufacture, cost-effective, versatile and suitable for a wide range of metals.
Perforated Metals - Metalex
Perforated Metals - Metalex
Perforated Metals - Remaly Manufacturing Company, Inc.
Perforated Metals - Astro Engineering & Manufacturing
Perforated Metals - Astro Engineering & Manufacturing
Perforated Metals - Astro Engineering & Manufacturing
Perforated metals, as its name implies, are pierced metal sheets that are fabricated from various processes to give different patterns and shapes-either decorative or functional, or both. Based on a specific need or design, different metal sheets are utilized for making perforated metals and therefore, perforated aluminum, perforated copper, and perforated stainless steel are readily available to manufacturers.
For decorative purposes, perforated metals have been in use for centuries. However, perforated sheets came into use during the 19th century for coal separating screen purposes. Those screens were manually perforated. With the development of manufacturing and fabrication of new technologies, custom presses with dies for perforated metals later came into existence. Presses and related technologies such as rotary pinned perforation rollers and laser perforation, changed the manufacturing landscape. These advancements made fabrication so efficient and consistent that perorated metals started to compete with other alternatives and were used in construction at a large scale, from access control sheets to acoustic control measures and heat saving facades.
The most common applications of perforated metals include:
The architectural use of perforated metals has surpassed other applications. In recent environmental studies, variations of sheets such as panels, sunshade, and cladding have been proven to substantially save energy. Thus, in addition to aesthetic fittings, sheets are helping architects and builders design eco-friendly buildings that can offer an energy savings of up to 25 percent. Moreover, perforated sheet metals are used for signage, fencing and access control, and column covers.
Before the advent of modern technology and perforated sheets, bees were harvested in containers without movable frames. Bees used to make their own hives within these structures; however, a single harvest could destroy a whole enclosure, and bees had to start from scratch. Modern beehives made from perforated metals solve this issue. Other than the honey industry, perforated sheets are extensively used in food processing, where they are used as grain dryers. The other common usages of perforated metals are as screens for fish, silo ventilation, juice presses, wine vats, and cheese molds.
Use in Chemical & Energy Industries
The most extensive use of perforated sheets is as filter mechanisms. There are a multitude of equipment types that contain filters made from perforation techniques, including centrifuges in laboratories; drying baskets in washing machines; separator plates in batteries; screens in gas, water, and air purifiers; as well as conventional coal washing and mine cages.
Supplanting Material Development
Perforated metal, along with wire forms, is utilized for strengthening glasses used in extreme manufacturing environments. Similarly, they are used in the manufacturing of screens of cement slurry, textile printers, felt mills, dyeing machines, as well as blast furnace screens, which are specially designed to withstand high temperatures.
The most common use of perforated metals, other than on building facades, is in the automobile industry. Grills, running boards, and silencers all are manufactured with perforated sheets of different metals, based on need. Moreover, almost all filters, whether they are oil filters, air filters, or ventilation grids, are made with perforated sheets.
When it comes to the functionality of perforated metals, they have come a long way from simply being used as screens for filtering coal or in the design of climate control equipment like sound proofing material. Similarly, the aesthetic adoption of perforated metal sheets has also increased, as they are now integrated with building facades-not only adding architectural creativity but also helping to contribute to up to a 25% savings in energy consumption.
This change in the use of perforated sheets has come with the arrival of different fabrication methods which add efficiency and give consistent results while eliminating human errors.
The following paragraphs describe the different manufacturing methods used in producing perforated sheets.
The first step in manufacturing perforated metal includes finding the appropriate material. Based on your unique manufacturing needs, different sheets are available such as perforated aluminum, perforated steel, and perforated copper; each has specific utility and characteristics. A perforated aluminum sheet has applications in the refurbishment of offices, railings and stairways, and cutting technologies like Micro-Electro-Mechanical Systems (MEMS) capacitive microphones. Similarly, other sheets have applications in the production of filters, from oil to water to gas.
Therefore, choosing the most appropriate metal sheet is important. The sheets come in variable thicknesses and are measured in gauges-the larger the gauge number, the thinner the sheet. Determining the appropriate sheet gauge is as important as selecting the metal itself.
The perforated metal sheets used for fabrication are mostly thin and flat, which are then bent, welded, punched, and cut using following methods.
Rotary Pinned Perforation Rolling
Many manufacturers consider the process of rotary pinned perforation rolling as the most efficient method for fabricating perforated metal sheets. In this method, as the name suggests, a rotary pinned perforation roller is used, consisting of a large cylinder with sharp and pointed needles. Using the needles, holes with varying diameters can be punched into the metal sheets, as the sheets move across a perforation roller. To reinforce the perforation, the needles on the roller are sometimes heated continuously, causing the metal to melt and form a ring around the hole. As this process is streamlined, the holes are punched continuously, making the method cost effective and efficient. For making holes of varying circumferences, different needles are used.
Die and Punch Perforation
To make perforated sheets, die and punch perforation is as common as rotary pinned perforation rolling. The method is simple-a die punches a hole in the sheet driven by a press, which can mechanical or hydraulic. Unlike the first process, which has a single point of operation and eliminates secondary procedures, die and punch perforation requires secondary processing, as the remaining metal is sheared off to make the surface smooth. However, the method is preferred when large surfaces of sheets need to be punched.
The most modern method of perforated metal production includes the use of laser technology. Since this method is quite expensive it is used only when precision is a factor. Laser perforation gives high consistency.
Among the technologies employed for producing perforated metals, the most effective and efficient is press and punch perforation forming. With the most modern perforation presses, it is now possible to produce any conceivable perforation pattern since computer programming has been integrated into machine operation and offers extreme precision.
To serve different needs, there are a number of techniques used in press and punch perforations. These techniques are described in the paragraphs below.
Wide press perforation is the most common perforation technique, as it is the quickest and most cost-effective. Using this method, in each strike of die on a plate, the entire width of the plate is punched. As the plate moves through the machine, a punch row or an array of punch rows work simultaneously. Wide press perforation is a rapid process and it is common to find stress faults due to punching. Moreover, the tooling cost is high. Therefore, wide press is considered the best option for processing high volumes of metal.
To rectify stress faults or distortions, a leveler is used. With a leveler, stress errors are removed by flattening the processed plates. The leveling procedure is not a standard procedure and depends on the location of non-perforated and perforated areas.
When a machine works only on a specified area or section versus the entire width of a sheet, sectional punching is often a preferred technique. As the work is performed only in a small section, the production rate is significantly lower than with wide press processing. However, sectional press tooling is less expensive than the alternative. Sectional presses can be used when tailored products with specific perforation patterns are needed. With the advent of modern Computer Numeric Control (CNC) equipment, the perforation areas and patterns can be easily pre-programmed into press machines. The sectional press method is used when a plate is thick-up to 20 mm-as less punches are required.
Automatic Nibbling Machines
This technique does not vary much from the sectional press method, as the machine works only on a section of the plate. However, the production is automated and the tools needed for perforations are changed without manual interference. The processing machine also nibbles the contours. With this machine, various perforations can be made economically. Moreover, the machine is competent at finishing the outer plate of contours if required.
The other processes involved in manufacturing metal plates are leveling, plate shearing, folding, welding, surface polishing, and rounding.
For shearing, a straight plate shearer is typically used, however, in some high-precision processing, lasers are used. For bending, a CNC machine is commonly used, which suits even complex profiles. For welding, either a metal inert gas (MIG) or a tungsten inert gas (TIG) is used.
To post process the surface of plate, grinding and brushing techniques are typically employed. Sometimes, for different applications, the plate is polished-either mechanically or with the use of electric methods-and then de-greased and blasted with beads and sand.
Perforated metals, including a wide of range of sheets with punched patterns, shapes and slots, have application in a variety of industries. Among these applications, perforated metals used in acoustic equipment have seen the most recent growth in adoption.
Applications of perforated metals include their use in the production of protective coverings, sound absorbers, and diffusers. Each of the applications is described in the paragraphs below.
Today's architects are realizing the capabilities of perforated sheet metal as a decorative covering for acoustical materials that can reflect, scatter, and absorb sound waves. Perforated metal sheets uniquely suit this purpose, as the perforations let the sound waves pass through the covering and reach acoustic equipment installed behind them. Perforated metal sheets allow varying sound frequencies to pass through.
Sometimes, perforated metals sheets are used for absorbing sound waves of specific a frequency. When you need to selectively filter out sound waves of specific frequency, resonant sound absorbers made from perforated sheets can be used. Unlike the first application, where they are used for sound transparency, the sheets play an active part in the sound cancelling process.
When perforated metals are used as resonant sound absorbers, they are fabricated in a way that traps a layer of air and modifies their performance. There are other materials that have been used as alternatives, however, perforated metal makes resonant sound absorbers efficient-especially when tuned to 120 Hz. The use of metal sheets has eliminated the need of large spaces and thick layers of absorptive materials in acoustical settings.
To make use of the most efficient resonant sound absorber, the first factor to determine is the desired frequency of maximum absorption. The other factor is calculation of the dimensions of the tuned absorber using a nomogram.
To provide acoustical properties, perforated metal sheets are occasionally used in aerodynamic test facilities, including wind tunnels. The perforated metals break up the turbulence of the airflows.
Perforated Metals versus Other Acoustical Alternatives
Choosing the Proper Perforated Metal
Many different methods are used to give sound transparency properties to perforated metals. A manufacturer could process an entire opaque metal sheet with a single hole in the center, which lets sound waves enter. Conversely, an entire sheet could have perforations and become completely transparent.
Designers choose the best option based on the transparency index, which states that, when high transparency sound waves are involved, closely spaced perforation sheets work better. The transparency index usually increases as the open area increases.
Perforated Metal Terms
device that attaches the perforated metal grating to its supports.
- Flat metal bars connected to each end of the bearing bars of a perforated metal grating.
- Individual strips of metal that make up perforated metal grating panels; they support the load applied to the perforated metal grating.
- The point of intersection between two strands of expanded metal.
- Angles or flats that get welded to the perforated metal grating.
- The process of moving unheated metal through pairs of roller dies to increase strength and reduce thickness. Expanded metal is flattened in the cold rolling process.
- The bars perpendicular to the bearing bars of expanded metal grating.
- The amount of deformation that occurs upon the application of stress to perforated metal grating. Acceptable deformation usually measures about 0.25.
- A coating applied to perforated metal grating. This coating is typically paint or galvanizing.
- The distance measured in inches between two bond midpoints.
- The openings or gaps in expanded and perforated metals that are surrounded by metal strands.
- A manufacturing method for perforated metal grating in which a specialized press, fit with cross-bar deformation, locks the bearing bars in position. The press-locked method is an alternative to riveting and welding.
- A shearing method that leaves prongs or jagged edges on the expanded metal.
- The inclusion of a row of notches on expanded metal grating to provide slip resistance.
- Process of trimming metal to meet size and shape design requirements.
- Process whereby metal strip width is reduced to meet design criteria.
- In expanded metal, the metal strip creating the pattern framework.
- A panel of grating to which carrier end plates and nosing are welded. Tread is designed specifically to be used as stairs.