Jul. 28, 2025
Manufacturers often create expanded metal products for both decorative and functional purposes. These versatile industrial materials offer a robust yet lightweight solution, enhancing the strength and durability of any product made partially or entirely from them. Expanded metals provide protection while still allowing air, light, and fluids to flow through, making them an ideal choice for a wide range of commercial, architectural, and industrial applications. Whether you are seeking expanded metal sheets for construction, expanded metal mesh for fencing, or specialty expanded metal panels for architectural design, understanding the benefits and applications of this material can help you make an informed purchasing decision.
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Expanded metal is a versatile material utilized in a myriad of applications, making its way into numerous products thanks to its unique characteristics and superior performance. One of the most prevalent products crafted from expanded metal is expanded metal grating. This type of grating is extensively employed in industrial settings, walkways, catwalks, safety platforms, mezzanines, and manufacturing plants. Its open design facilitates efficient drainage and natural ventilation while offering robust support for heavy loads and foot traffic. Heavy-duty expanded metal grating is often chosen for areas that require both strength and slip resistance, such as loading docks, stair treads, and maintenance platforms.
Another significant use of expanded metal is in fencing and security products. The interlocking pattern of expanded metal is ideal for fencing, providing both visibility and security in various environments, such as airports, prisons, correctional facilities, sports arenas, and commercial properties. Expanded metal fencing creates strong barriers that are difficult to penetrate or vandalize, making them a preferred option for perimeter security and property protection.
Expanded metal is widely utilized in architectural and decorative applications, offering both functionality and visual appeal. Architectural meshes crafted from expanded metal enhance the aesthetic of buildings and facades, delivering a distinctive and contemporary look. These meshes serve as sunscreens, privacy screens, and artistic installations, allowing designers to creatively manipulate light and shadow. In modern architecture, expanded metal facades are used to create innovative building exteriors, sunshades, and cladding systems that combine beauty with energy efficiency.
Furthermore, expanded metal is used in automotive products like radiator grilles, battery covers, heat shields, and protective covers, valued for its lightweight and durable properties. In the transportation industry, expanded metal parts are preferred for their ability to withstand impact while minimizing weight, contributing to fuel efficiency and vehicle safety.
In the realm of filtration and screening, expanded metal plays a vital role. It’s used to create air filters, oil filters, and screens for a variety of industrial processes. The precise openings in the expanded metal facilitate efficient filtration, making it the ideal choice for separating particles in liquids and gases. Expanded metal screens are commonly found in HVAC systems, water treatment facilities, and food processing plants.
Furthermore, expanded metal plays a crucial role in the construction industry as reinforcement for concrete and masonry. When used as concrete reinforcing mesh, expanded metal significantly enhances the structural integrity and load-bearing capacity of concrete structures, thereby improving their durability and safety. Expanded metal lath is commonly used as a plaster base in stucco and masonry work, providing better adhesion and crack resistance.
Other notable applications include machine guards, shelving, partitions, cable trays, speaker grilles, and lighting fixtures. The adaptability of expanded metal makes it a prized material across numerous industries, resulting in the creation of an array of diverse products. Whether used in grating, fencing, architectural meshes, automotive components, or filtration systems, expanded metal is crucial in fulfilling structural, functional, and aesthetic needs in a variety of applications.
In , John French Golding revolutionized the mining industry in the United Kingdom with his invention of the expanded metal process. His aim was to create a durable tray or metal screen that miners could use to sort coal more efficiently. Prior to Golding’s innovation, miners relied on sorting tools crafted from metal strips or woven wire, which were both inefficient and lacked standardization, as well as strength. Golding’s breakthrough involved using a single metal sheet, resulting in screens far more durable than their predecessors. Moreover, the expanded metal process produced screens with consistent and uniform open areas, greatly enhancing their effectiveness for sorting and filtration.
Five years after pioneering metal expansion, Golding and a group of industry experts combined their knowledge and research to establish a new company. Initially named the British Metal Expansion Company, it was later rebranded as the Expanded Metal Company Limited, based in London. For several years, the Expanded Metal Company held a monopoly on metal expansion in Europe, possessing exclusive rights to the process. This early dominance helped establish expanded metal as a standard industrial material throughout Europe and beyond.
In the s, Eli Hendrick, an American innovator, invented the punching machine, which served as the precursor to modern perforating punches. These perforating punches enable the creation of perforated metals, closely related to expanded metals, and opened new possibilities for industrial filtration, screening, and ventilation products.
Charles H. Schrammel was the first person in the United States to receive a patent for expanding metal. Awarded in , his innovative work significantly improved the metal expansion process. Schrammel introduced sheet metal rolling to the process and altered the angle of metal mesh dividers, resulting in better textures for gripping and enhanced performance in safety applications.
Over the past century, the metal expansion process has largely remained consistent, with notable advancements driven by technological progress. Innovations such as automation, digital perforation, the establishment of standards organizations, and the advent of CNC machining have revolutionized the field. While the rise of plastics has slightly reduced the market share for expanded metals, the industry continues to flourish. Recently, a revived interest in classic architectural styles has spurred renewed demand for architectural perforated and expanded metals, leading to a significant increase in business for the expanded metal products industry. Modern manufacturers now offer a wide range of custom expanded metal solutions to meet the evolving needs of the construction, automotive, and design sectors.
Manufacturers craft expanded metal products from a variety of metals, with copper, aluminum, stainless steel, and titanium being the most frequently chosen. These metals are known for their exceptional strength and corrosion resistance, while still maintaining a relatively lightweight profile. After expansion, they can all be cold rolled to reduce their thickness, ensuring a more uniform and smooth surface. Selecting the right material is key to achieving desired properties such as durability, conductivity, corrosion resistance, and weight savings.
Copper, a naturally occurring non-ferrous transition metal, is renowned for its exceptional electrical and thermal conductivity, antimicrobial properties, corrosion resistance, strength, and distinctive color. Manufacturers harness the versatility of copper expanded metal to create a diverse array of products, including metal grating, enclosures, filters, radiators, walkways, heat sinks, decorative ornaments, and intricate decorative metal mesh. Copper expanded metal mesh is also used in EMI/RFI shielding, electrical enclosures, and architectural accents where both performance and appearance matter.
Aluminum, a naturally occurring element, is rarely used in its pure form but stands out for its lightweight, durability, and superior corrosion resistance compared to carbon steel. Notably, aluminum strengthens in cold temperatures instead of becoming brittle. Expanded aluminum is versatile, finding applications in refrigerator and freezer enclosures, guards, flooring, walkways, grilles, electronic and automotive components, marine and aquarium parts, cooking tools, and air filters. Aluminum expanded metal sheets are a top choice for projects that require a balance of strength and weight reduction, such as aerospace, marine, and transportation equipment.
Stainless steel, an alloy containing a minimum of 10% chromium, boasts a thin layer of chromium oxide on its surface. This unique feature grants expanded stainless steel products self-repairing capabilities when scratched, along with exceptional resistance to corrosion and rust. Compared to other steel alloys like mild steel, stainless steel is stronger, more durable, and highly resistant to bacteria. These attributes make expanded stainless steel invaluable in diverse environments, from kitchens, clinics, hospitals, and laboratories to outdoor applications, vehicles, buildings, water treatment plants, marine settings, and airplanes. Stainless steel expanded metal mesh is frequently specified for food processing, chemical handling, clean rooms, and architectural projects demanding high performance and hygiene.
Titanium boasts exceptional strength, lightweight properties, resistance to corrosion and heat, and sterility. It matches steel in strength while being 45% lighter. Its biocompatibility makes it ideal for surgical and orthopedic applications. Expanded titanium is highly sought after in military and defense, aerospace, automotive, electronics, and healthcare industries, where strength-to-weight ratio, reliability, and inertness are critical.
Other materials sometimes used for expanded metal products include carbon steel, galvanized steel, nickel, brass, and specialty alloys. Each material offers specific advantages based on the application, environment, and budget. For example, galvanized expanded metal offers superior corrosion protection in outdoor or wet settings, making it a popular choice for fencing, walkways, and construction reinforcement.
In transforming metal sheets into expanded metal products, manufacturers begin with the expansion process. Following this, the sheets are shaped and formed to meet custom specifications. For a deeper understanding or to find suppliers that offer custom expanded metal fabrication, continue reading:
Are you wondering how to select the best expanded metal for your project? Consider factors such as material, thickness (gauge), pattern (SWD/LWD), open area percentage, and finishing options to ensure optimal performance and appearance. If you need help with custom fabrication, be sure to request a quote or consult with an experienced expanded metal manufacturer for expert guidance.
When manufacturers engage in the expanding metal process, they must carefully consider several factors. Primarily, they need to determine the shape and size of the hole patterns in the expanded metal products according to the specific application requirements. They also need to take into account standard specifications, choose the most suitable metal based on its properties, select the appropriate metal gauge (thickness), and decide on the overall dimensions (length, width, etc.) and texture.
To determine the size of the open areas they plan to create during metal expansion, manufacturers use two measurement methods: SWD and LWD. SWD, or “short way of the diamond,” refers to the width of the openings. LWD, or “long way of the diamond,” indicates the length of the openings. These measurements are calculated based on the required density of air, water, or other substances that must pass through the metal pattern. Properly specifying SWD and LWD ensures that the expanded metal mesh meets the necessary performance for filtration, screening, or structural support.
To tailor an expanded metal product, manufacturers can shape the metal to any specification and apply a variety of paints or coatings. They also have the flexibility to design custom hole patterns. For buyers, understanding these design options is vital—whether you are seeking decorative expanded metal panels for architectural facades or heavy-duty security mesh for fencing applications.
Looking for help specifying expanded metal mesh for a unique application? Contact an expanded metal supplier with your requirements for expert design assistance and material selection recommendations.
Manufacturers utilize a variety of machines and tools to execute the metal expansion process and the subsequent parts forming procedure. This includes expansion presses, flattening presses, dies, and hot rolling presses. The choice of machinery impacts the quality, speed, and customization capabilities of the finished expanded metal products.
Expansion presses work by pushing metal outward with a stretcher bar while cutting slits into the metal with mechanical knives. Manufacturers typically prefer automated CNC expansion presses over manual ones for their efficiency and precision. CNC-controlled expansion presses can produce intricate, repeatable patterns, enabling rapid production of high-quality expanded metal sheets, mesh, and panels.
Flattening presses live up to their name by flattening and smoothing metal sheets. They are used after perforation and expansion, working through cold rolling. In this process, parallel cylinders apply pressure to the metal as it moves between them, squeezing it into a smooth, even surface. Flattened expanded metal is often specified for architectural, industrial, and safety applications where surface flatness and smoothness matter.
Dies are specialized manufacturing tools that work with presses and forming machines. Crafted primarily from metal, these tools are engineered to match the shape of the intended product. When material is fed through or pressed into the die, it is cut and shaped according to the die’s design. Custom dies allow for the production of unique mesh patterns, custom openings, and specialty products tailored to customer needs.
Hot rolling presses are designed with rollers to flatten metal by working it at temperatures above its recrystallization point. This distinguishes them from cold rolling presses, which operate at lower temperatures. The combination of hot and cold rolling processes gives manufacturers flexibility in achieving the desired material properties and surface finishes.
Interested in learning more about the equipment used in expanded metal manufacturing? Explore our resources on expanded metal machinery or request a facility tour from a local supplier to see the process in action.
Perforated metals and wire mesh are closely related to expanded metals. Perforated metals feature sheets with evenly spaced holes punched into them, while wire mesh is created from interwoven wires forming a grid pattern. Both materials, much like expanded metals, find application across diverse industries for tasks such as filtration, screening, fencing, and architectural design.
While each of the three processes has its own benefits, expanded metals stand out in particular scenarios. They are notably lighter than perforated metals, which simplifies handling and installation. The manufacturing process for expanded metals involves slitting and stretching a single sheet of metal to create a pattern of interlocked strands. This unique structure gives expanded metals added strength and rigidity, often making them more durable than perforated metals, especially in high-stress situations. Expanded metal’s one-piece construction eliminates weak points, making it ideal for safety barriers, machine guards, and impact-prone areas.
Expanded metals offer greater versatility and customization compared to wire mesh. Their openings and patterns can be adjusted to meet specific needs, allowing for a wide range of designs and functions. In contrast, wire mesh is constrained by the thickness and arrangement of its wires, limiting its customization options. Additionally, expanded metals provide improved visibility with more pronounced openings, making them ideal for applications requiring transparency, such as architectural facades and safety barriers. The ability to specify mesh opening size and pattern gives expanded metal an edge in light diffusion, privacy screening, and airflow management.
They also offer the advantage of efficient material use. The manufacturing process involves stretching the metal rather than removing it, resulting in minimal waste. This approach not only leads to cost savings but also makes the production process more environmentally friendly compared to techniques that produce more scrap material. For companies seeking sustainable building materials or aiming to comply with green construction standards, expanded metal is a compelling choice.
In summary, although perforated metals and wire mesh excel in their respective applications, expanded metals provide distinct advantages that often make them the preferred choice. Their lightweight nature, inherent strength, and versatility offer exceptional durability and cost-effectiveness. Moreover, their efficient material usage and enhanced visibility make expanded metals superior to other products in specific contexts, from industrial platforms to modern architectural masterpieces.
Still deciding between expanded metal, perforated metal, and wire mesh for your project? Compare product specifications or consult with an expanded metal specialist to identify the best solution for your application.
Expanded metals offer numerous advantages, making them a popular choice in various industries. Their open design enhances ventilation and drainage, providing significant benefits. Whether used as grating in industrial environments, walkways, platforms, or as screens for air or liquid filtration, the interconnected pattern ensures efficient airflow and fluid passage. This feature is particularly valuable in applications where proper ventilation or drainage is crucial for optimal performance and safety, such as chemical processing, water treatment, and building construction.
They offer remarkable versatility, allowing for customization of opening sizes and shapes to suit diverse applications. Their adaptability makes them ideal for a range of uses, from architectural facades to automotive parts and concrete reinforcement. This flexibility ensures that expanded metals can meet a variety of design and functional requirements. For example, custom expanded metal panels can be engineered for acoustic control, sun shading, or aesthetic enhancement in commercial buildings.
Additionally, expanded metals are low-maintenance due to their robust construction, which endures harsh environmental conditions. This makes them ideal for outdoor use where exposure to weather, moisture, or chemicals is common. Their minimal upkeep leads to lower costs and a longer product lifespan. For facility managers and property owners, this translates to reduced total cost of ownership and fewer replacement cycles.
Moreover, expanded metals are environmentally friendly because their production process optimizes material use. The stretching technique generates minimal waste, leading to a reduced environmental impact compared to other manufacturing methods. Many manufacturers also offer recycled-content expanded metal products, supporting LEED certification and sustainable building practices.
Expanded metal products are also easy to install and modify. They can be cut, shaped, welded, or bolted into place, making them suitable for both new construction and retrofit projects. Their anti-slip surfaces, resistance to tampering, and high load capacity make them a trusted choice for public infrastructure, safety walkways, and security fencing.
In summary, expanded metals offer significant advantages across various applications. Their superior ventilation and drainage properties, combined with their versatility and low maintenance needs, make them a practical and reliable choice. Additionally, their eco-friendly production process further enhances their appeal. These benefits position expanded metals as an excellent solution for diverse industries, including construction, architecture, filtration, automotive, aerospace, marine, security, and more.
Ready to discover how expanded metal can improve your project? Contact a leading expanded metal manufacturer for application guidance, samples, and pricing information.
Metal expansion isn’t overly complex, but the difference between an experienced service provider and a novice can be significant. For the best results, partnering with someone who has both extensive experience and a solid reputation is crucial. To assist you, we’ve compiled a list of our most trusted expanded metal suppliers. You can find their company information and profiles interspersed between the paragraphs above. These expanded metal manufacturers offer a wide range of products and custom fabrication services to suit any requirement, from small-scale architectural mesh to large-scale industrial grating.
Before diving into your search, we recommend taking some time to compile a list of your own. Include all your specifications, questions, and concerns. Once your list is ready, use it as a guide during your search. Eliminate any company that doesn’t meet your requirements. Select three or four expanded metal manufacturers that catch your interest and reach out to them. Be sure to discuss your budget, timeline, and delivery preferences. After speaking with each, compare the responses to determine which manufacturer best suits your needs and move forward from there.
Key questions to ask when choosing an expanded metal supplier include:
Taking the time to research and vet suppliers will ensure you receive high-quality expanded metal products that are tailored to your application, delivered on time, and priced competitively. For additional resources, view our expanded metal manufacturer listings or explore our expanded metal FAQs to answer common buyer questions.
Expanded metal is a specific form of sheet metal mesh that is produced by elongating a slitted sheet of ductile metal. The slits are strategically placed perpendicular to the direction of stretching, creating a mesh composed of multiple holes from the slitted sections.
The concept behind expanded metal is grounded in the natural tendency of metals to expand and contract when exposed to varying conditions. This tendency is governed by the metal's atomic structure and inherent chemical properties, leading to the formation of expanded metal.
Expanded metal can be compared to and is often an alternative to other types, including:
Perforation involves the creation of holes within a sheet of metal. This leads to a (metal) perforated sheet. Many of the same sheets that are capable of being perforated can also undergo expansion. Perforation is essentially a subtractive method where the formation of holes leads to material loss, often considered waste. Unlike expanded metal, perforation typically doesn't involve stretching the metal sheet. Its benefits include the ability to produce tiny openings and drainage casings for various uses. It also allows for unique shapes, especially for decorative applications.
Perforated sheets are frequently utilized in the design of computer casing enclosures.
This technique involves interlacing metal wires much like weaving fabric threads. The integrity of the weave is maintained through friction and the wires' stiffness since no bonding occurs between the separate wires. Unsecured edges may unravel. Woven mesh is commonly used for sieving sand and related applications.
This mesh consists of two grids of parallel wires superimposed at 90-degree angles to one another, secured at each crossing point with welds. It is ideal for spanning large areas. Finely spaced meshes present production challenges due to the dense requirement of welds per unit area.
Welded mesh is often used to reinforce concrete structures and enhance their durability.
Expanded metal is manufactured from a wide range of metals that can be stretched and formed without fracturing, offering unique advantages for architectural, industrial, and structural applications. While virtually all malleable metals are candidates for expansion, only select types are commonly used in commercial and engineering contexts due to their performance characteristics, availability, and cost-effectiveness. The following section provides an overview of the primary material types used for expanded metal mesh, highlighting their properties, advantages, and most suitable use cases.
Historically, copper isn't typically the primary choice for structural applications, particularly when only structural factors are considered. Additionally, copper is relatively expensive, especially when assessed per unit volume. Volume is crucial as it affects the final size of the expanded metal sheet. The high density of copper is a disadvantage in applications where weight is a critical factor, such as in rigging.
Copper becomes relevant when factors beyond just structural concerns are important. These considerations include:
With its combination of electrical and thermal conductivity, corrosion resistance, and formability, copper expanded metal mesh offers a niche solution for projects requiring superior aesthetic and functional performance.
Aluminum has a wide range of structural applications due to its strength and lightweight nature. It is an effective conductor, which is why it's often used in overhead power lines.
Aluminum's malleability makes it easier to work with than steel (when cold), and its resistance to corrosion adds to its advantages. With a high melting point and excellent thermal reflectivity, aluminum is well-suited for high-temperature environments.
Expanded aluminum mesh is highly valued in both industrial and architectural contexts, offering an optimal balance of durability and low weight. Its properties include:
Its combination of strength-to-weight ratio, corrosion resistance, and adaptability positions expanded aluminum mesh as a top choice in industries such as construction, transportation, filtration, and electrical components.
Steel is the most widely used structural metal, known for its exceptional strength compared to other metals listed here, provided it remains free from corrosion. Steel expanded metal sheet is highly versatile, lending itself to applications in security, heavy-duty fencing, industrial flooring, machine guards, and architectural facades. Steel comes in several main types for expanded mesh applications:
This provides a robust and economical solution. It is commonly coated with molten zinc through a hot-dipping process for galvanization. Galvanized expanded mild steel delivers excellent cost-effectiveness, strength, and corrosion resistance, making it an ideal material for perimeter fencing, grating, catwalks, platforms, and non-slip walkways in warehouses and factories.
This expanded metal sheet is made from higher gauge metal sheets, typically crafted from mild steel. Expanded metal grating is used in heavy-duty settings, including industrial flooring, security panels, and machine platforms requiring high load-bearing capacity and slip resistance. It is often chosen as an alternative to welded grating for enhanced strength and efficient weight distribution.
Stainless steel offers greater resistance to corrosion compared to mild steel and is more effective in high-temperature environments. Stainless steel expanded metal mesh is commonly used in settings requiring both superior hygiene and resilience, such as food processing, pharmaceutical plants, architectural cladding, and chemical filtration systems.
Key benefits include:
Choosing the proper material for expanded metal panels, mesh, or grids largely depends on your application's requirements – from load-bearing capacity and environmental exposure to visibility, security, and decorative needs. To ensure the best value, evaluate each metal's properties in the context of your project's performance and budget constraints.
The production of expanded metal is a precise, multi-stage process that transforms solid sheet metal into versatile, mesh-like products widely used across construction, industrial, architectural, and security applications. Understanding these manufacturing steps is essential for those seeking reliable, high-quality expanded metal mesh for custom projects or industrial purposes. Below, we outline each key stage of the expanded metal manufacturing process, highlighting important material characteristics, dimensional factors, industrial procedures, and quality considerations.
The initial step in producing expanded metal is the careful selection of appropriate sheet metal materials. This choice is crucial, as the base material determines the finished expanded metal's performance, durability, lifespan, and suitability for a specific application or environment—such as walkway grating, security fencing, filtration screens, architectural cladding, or decorative panels.
When selecting the metal, manufacturers assess the following key properties—each of which impacts the mesh's intended function and resistance to wear:
In addition to the metal’s chemical and structural properties, accurate dimensional specifications—such as thickness, width, and length—are crucial to achieving the desired expanded metal size, pattern, and mesh type.
Before manufacturing begins, the dimensions of the raw metal sheet must be clearly defined. These physical properties influence the mesh’s final performance, layout options, pattern repeat, and cost efficiency. Core dimensional aspects of expanded metal sheets include:
Related links:For more information, please visit perforated metal supplier.
These dimensional variables are crucial not only for creating the correct expanded mesh geometry, but also for optimizing manufacturing efficiency, reducing waste, and customizing the product for diverse uses—from anti-slip walkways and machine guards to architectural facades.
The core process in expanded metal manufacturing involves simultaneous slitting and stretching. The sheet metal passes through a specialized press and die system, which cuts a precisely engineered pattern of slits and then stretches the material to form the characteristic mesh structure without wasteful scrap (unlike perforated metal). This step sets the final size and shape of each opening, producing a strong and continuous mesh sheet.
Typically, a die first defines half a row across the sheet’s width. With each stroke, the die cuts and stretches the metal in one motion (producing the initial half row), then retracts before shifting for the next cut. The feed rate of the metal sheet and the movement of the die are carefully coordinated to produce uniform mesh or allow variation for custom expanded metal products.
To ensure consistent and accurately shaped openings in the mesh, a single die may be used for standard configurations. For complex or mixed patterns, complementary dies alternate, enabling production of mixed or designer meshes.
This method yields an expanded metal sheet with a pronounced, elevated structure often referred to as standard expanded metal. This type is recognized for its strength-to-weight ratio and anti-slip qualities, making it ideal for industrial safety grating and security mesh installations.
During production, coolants and lubricants are commonly used with expansion presses. These residues may aid in corrosion prevention but must be removed if post-processing (such as powder coating, painting, or galvanizing expanded metal) is required for aesthetic or corrosion resistance in harsh environments. Removal is generally achieved with specialized detergents or solvent cleaning.
This process minimizes waste and allows the creation of both lightweight and heavy-duty expanded metal products with tailored mechanical properties.
Diamond shape: This standard expanded metal pattern is widely used for its effective balance of strength, ventilation, and visual appeal. Diamond mesh is the industry norm for platforms, security panels, and fencing.
Hexagonal shape: Popular in applications that require additional rigidity or unique aesthetics, hexagonal openings are created by modifying the direction of expansion. These are commonly chosen for architectural and filtration products but require advanced tooling and greater production control.
Square shape: Achieved when the mesh’s diagonals are of equal length, square expanded metal provides uniformity and is frequently used for machine guards, shelving, and decorative grilles.
Louvered: A specialized pattern where sections are bent or pressed to alter airflow, sun shading, or drainage characteristics. Louvered expanded metal is often used for ventilation covers, screens, and sun-shading facades.
Decorative: Custom shapes—such as circles, ovals, or branded motifs—may be produced for artistic, signage, or specialty architectural expanded metal designs that meet unique visual and functional requirements.
Strand thickness, or the width of the metal remaining between the cuts, is a key design feature of expanded metal mesh. It determines the percentage of open area (critical for airflow, visibility, or filtration), mesh rigidity, and structural load capacity. Adjusting the feed rate during extrusion modifies strand thickness, allowing manufacturers to balance strength-to-weight ratio and function based on client specifications.
In applications that require robust support—such as expanded steel grating or industrial mesh panels—a thicker strand may be specified. For lightweight screening or facade systems, thinner strands maximize openness and visibility. Strand thickness can even be varied within a single mesh sheet for customized solutions.
Flattening is a secondary process that delivers a smooth, planar surface to the expanded metal, removing the raised or ridged finish typical of standard expanded mesh straight from the machine. While the raised (standard) finish provides slip resistance and rigidity, some applications—such as architectural facades, ceiling panels, or parts requiring close contact with substrates—demand a smooth, flattened expanded metal finish.
This is achieved through a cold rolling process, compressing the mesh to reduce thickness, elongate the openings, and produce an even surface. Flattened expanded metal offers improved workability for forming, bending, or welding, and is commonly specified where aesthetics, safety, or mounting precision is critical.
It’s important to note that flattening alters the dimensions of the openings, resulting in slightly elongated shapes compared to standard expanded metal mesh. This factor must be considered when specifying dimensions for final installation or further fabrication.
Metal leveling, while often paired with flattening, addresses a different aspect—the overall planar geometry of the finished expanded metal sheet. During production and handling, sheets may develop minor waves or buckles, which can hinder installation or reduce the mesh's functional accuracy. Leveling is a finishing process that ensures the sheet lies truly flat to industry tolerances.
An expanded metal sheet is considered properly leveled when measurable flatness deviations (such as warping or bowing) fall within acceptable manufacturing tolerances. While achieving absolute flatness may be difficult due to the properties of expanded mesh, quality control standards ensure that finished sheets are suitable for precise applications in construction, enclosure building, or machine guarding.
Overall, a thorough understanding of the expanded metal manufacturing process helps buyers, engineers, and specifiers make informed decisions regarding mesh size, strand thickness, opening style, and finishing options for any project requirement.
This chapter will cover the topics of surface finishing and shearing for expanded metal.
In many cases, expanded metal sheets are utilized directly as they come from the roller or stretching machine, with no further modifications.
However, for certain applications, additional surface finishing is necessary. These include:
Painting is often the most economical method for finishing expanded metal sheets. Paint can be used for aesthetic purposes or to provide corrosion protection. However, for effective corrosion resistance, the paint must be fully intact; any small gaps can allow corrosion to develop underneath the coating. Of the coatings mentioned, painting is the least expensive, offers the least corrosion protection, and requires the most frequent maintenance.
This method often provides results similar to painting, but uses plastic instead. It tends to be more durable than painting. Typically, a spray gun is used to apply the plastic powder, which is often electrostatically charged. The coated sheet is then heated to bond the plastic with the metal surface.
In the galvanizing process, the expanded metal sheet is immersed in molten zinc, which forms a protective zinc coating. This coating helps safeguard the mesh from corrosion. However, due to the high temperatures involved, this method has limitations on the dimensions of the expanded metal that can be galvanized. Very fine meshes are generally not suitable for galvanizing due to these constraints.
Anodizing is an electroplating technique where the expanded metal sheet is coated while being electrically charged. This process provides a more granular coating compared to other methods and ensures a stronger bond with the metal. Despite its effectiveness, anodizing is relatively expensive, both in terms of the plating material and the process itself. Its higher cost is a primary reason for its less frequent use.
Anodizing is usually common with iron-based metals (which are prone to corrosion). This process circumvents some of the dimension limits that arise from the galvanizing process since it can be carried out at much lower temperatures.
Shearing is the process used to cut expanded metal sheets to size. It involves trimming a larger sheet into smaller sections or altering its shape. Shearing is performed with shears, which are metal blades or mechanisms that operate similarly to scissors. Shears can be either manual or mechanized. When the blades come together on the expanded metal, they apply sufficient shear force to cut through the material.
Various types of shearing methods exist, which will be discussed in the following sections:
This involves shearing along the longer axis of the diamond pattern.
Bond shearing cuts the sheet precisely along the edge, resulting in closed shapes only on either side of the cut. This method aligns with the shapes of the pattern.
For raised expanded metal, bond shearing should be performed along the bonds between the rows.
Random shearing does not follow the shape edges, resulting in open shapes and irregular patterns at the edges. This method can leave sharp, spiked strands. To improve handling, expanded metal that has been randomly sheared should be U-edged or framed as an alternative.
U-edging involves applying a U-shaped metal strip to cover the edges of an expanded metal sheet.
This involves shearing with a line of symmetry on the expanded metal sheet.
This technique creates a matching section, ensuring the mesh pattern appears continuous.
This method shears along the shorter axis of the diamond shape.
This involves cutting across strands at locations other than the bonds.
Among expanded metal shapes, the diamond (hexagonal) pattern is the most common. Typically, the same shape and size of openings are used consistently throughout a sheet. The diamond shape features four-sided openings with strands meeting at the corners.
As the difference between the diagonals of the diamond shape decreases, it begins to approximate a square (geometrically, a square is a special type of diamond where the diagonals are equal). In such instances, the mesh is referred to as a square mesh.
The hexagon does not need to be regular, but the side length determines the dimensions and strength of the bonds.
Tolerances for expanded metals need to be adhered to for:
Typically, expanded metal should be free from:
Expanded metal can be produced with different tolerances, which will be described below.
This refers to the bow or curve in the sheet. It may not matter if the expanded metal sheets are to be rolled for packaging, but it can be problematic for applications needing a flatter material. This is particularly true for materials requiring higher rigidity, which could result in residual stresses in the structure.
Producing expanded sheet metal with no camper is quite rare. Therefore, tolerances are established for specific applications. If the camper falls outside the required tolerance, corrective measures are necessary; otherwise, the material can be used effectively.
The curve typically forms along the edge in the direction of the feed during the cutting and stretching phase of the expanding process. Flattening, which often involves rolling, also addresses campers by removing or reducing them, along with waves and buckles, resulting in a more even product.
This refers to the property of having a rectangular or square shape, characterized by 90° angles and straight edges. In such geometry, the diagonals are equal.
Squareness is a planar characteristic, applicable to a single plane—the view from above when the sheet is laid flat. An expanded sheet can be square without meeting all other spatial and geometric requirements, such as being level. Conversely, issues like camper and buckles can affect the squareness of an expanded metal sheet.
Deviations from squareness often stem from the initial metal sheet, which is rarely perfectly square despite tight production tolerances, or from defects in the die used.
If the application permits, re-squaring can be achieved by random shearing the expanded metal sheet along specific lines. Border shearing generally does not correct squareness, and stretching the shorter diagonal often results in non-straight edges.
This feature is often crucial, especially when the expanded metal sheet has parallel opposite sides. Sheets that are perfectly square will always have parallel sides, but sheets with parallel sides are not always square (e.g., a parallelogram). Additionally, sheets without parallel sides can never be square. Deviations from parallelism may be caused by factors such as camper.
In certain applications, expanded metal may be intentionally made with non-parallel sides. For example, a die with varying "tooth" sizes across the sheet's width can create this effect from a square solid sheet. However, such applications are quite rare.
This refers to the deviation from having parallel sides, which becomes particularly noticeable when it is undesirable. A sheet with tapered sides cannot be considered square.
Often, expanded metal sheets require additional processing after they come out of the expanding machine. This may include cutting, bending, welding, bracing, and other modifications. Customization work is not usually part of the standard production process due to the unique requirements of each project. Additionally, some applications may need different gauges of expanded metal to work together effectively.
Customization involves modifications performed on the expanded metal sheet, typically based on specific customer requirements. These tasks may include:
This chapter will explore the uses and benefits of expanded metal.
Expanded metal is versatile and used in various applications, including:
Platforms designed for use at significant heights often incorporate expanded metal mesh to take advantage of its lightweight nature. Common applications include rigging in industries such as transportation, oil, telecommunications, and more.
Expanded metal can cover rotating shafts and machinery parts. It is lighter than solid guards but equally effective in safeguarding machine operators.
Expanded metal is used in structures to facilitate drainage and ventilation. It is commonly placed over drainage trenches along roadsides, walkways, factory floors, and similar areas.
Expanded metal mesh serves as protective screens for building and vehicle windows, including cash-in-transit vehicles.
Some bridges and suspended walkways use expanded metal for pedestrian areas to reduce the weight of the deck while maintaining structural integrity.
Expanded metal mesh is ideal for creating barriers where light, air, and sometimes water need to pass through. Such barriers are used in aquariums, buildings, tunnels, and other structures.
Expanded metal is used for protective fences, yard demarcation, animal cages, and other enclosures.
Expanded metal is suitable for making gabion walls, especially when finer aggregates are used, offering an alternative to welded mesh.
Expanded metal mesh can be utilized as a covering for equipment, offering a suitable solution when neither a solid sheet nor an uncovered area is appropriate.
Examples of equipment that might use expanded metal in their coverings include generators, tractor engines, earth-moving machinery engines, and both air and water pumps.
In architectural applications, expanded metal mesh is used in gardens, building openings, walls, roofs, guard rails, and demarcation walls. Fine meshes are also used in jewelry making.
Expanded metal mesh can be fashioned into trays used in agriculture, such as for harvesting and transporting green tea from fields.
Some recreational parks use expanded mesh on steep cliffs to provide thrill and entertainment.
While expanded metal has some drawbacks, such as increased surface area that can lead to corrosion and chemical damage, its benefits often outweigh these issues. Some advantages of expanded metal include:
It can be reasonably inferred that the need for expanded metal products will persist into the distant future. The combination of (relatively) light weight, high strength, and moderate cost will continue to place a distinct attractiveness on expanded metal products. The general trends of structural and industrial development also seem to agree – amongst other things, the requirement for civil structures to become increasingly taller will persist, with it the need for platforms, barriers and ornamentation.
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