Expanded metal products are ubiquitous in a number of industries not only because they are an economic option, but because they are extremely durable and rigid as well. Construction, architecture and water filtration industries, among others, use
expanded metal screens and
expanded metal mesh for furniture, waste treatment, bridge building, security partitions, walkways and even ornamental metal works.
Expanded metal fences and
expanded metal grating are also popular as alternatives to welded or interwoven components. The initial expansion process produces flat,
expanded metal sheets, which are a most basic and useful shape that can then be altered into other shapes as desired. To accommodate such versatility, manufacturers offer a variety of application specific materials and processes.
Copper expanded metal,
expanded aluminum,
stainless steel expanded metal,
expanded steel and
titanium expanded metal are widely available in both regular and
flattened expanded metal forms. Both of these forms must be cold-rolled after the initial process is complete. This further reduces the thickness of the material. The slightly round grid is given a uniform thickness and flatness.
Both regular and flattened metal expansion begins in the same manner. A metal sheet is fed into an expanding machine or press. While some manufacturers still use manual machines, most modern metal expansion is computer programmed and operated. This results in faster turnaround and often a more precise finished product. A die, manual or automatic, is used to pierce the sheet hundreds or even thousands of times. The cuts are evenly spaced in a uniform pattern with alternating lines up and down the width of the metal. As a row is cut, the machine continues to draw the metal through a hot rolling press. The heat and pressure cause the metal to expand while reducing thickness. The extruded sheet is a grid or mesh with open shapes and raised metal outlines. The shape depends on the specific die used. Although square, circular and other shapes are popular for decorative products, most industrial expanded metal is slit with a pyramidal die that produces a diamond shaped pattern. For regular metal expansion processes the last step is simply to check that the sheet is level. A level sheet with uniform holes can be used as the final product or undergo secondary processes such as bending.
The amount of pressure and heat required to complete metal expansion processes depends on several factors. The thickness of the original sheet must be considered as well as its material composition. The most common metals used for expanded metal products include aluminum, titanium, stainless steel, steel and copper. While specific traits will vary, each of these metals is durable and holds up well to corrosive environments and is relatively light-weight. In some cases, metal grids, meshes and screens are coated for additional protection. Galvanizing, painting, porcelain enamel coating, plastic coating and various other metal treatments may be used to increase product longevity or improve aesthetic quality of products that will be highly visible. In addition to the material, process and coatings, it is important to consider the open space created by expansion. This is measured in two ways. ‘SWD' refers to the short way of the diamond or opening, the width. ‘LWD' is a reference to the long way of the diamond or opening. It is important that these measurements be considered as they will determine the amount of light, air, water or any other substance or object that may pass through the mesh-like pattern of expanded metal.
Once the proper technique, material and dimensions are achieved, expanded metal can be used in any number of applications. Of all the industries that make use of this grated sheet metal, there are five predominant categories of use. Expanded metal enclosures are popular as they protect items while still maintaining visual access and allowing air and light to enter the cage or locker. Supports and storage encompass shelving, racks, trays and baskets made of expanded metal products. A more stable alternative to wire shelves, expanded metal is sturdier, but still has enough open space to prevent dust collection and allow the use of emergency sprinklers. Machine and heater guards offer further protection and, like the sprinklers, are required by federal, state and local laws and codes. In addition to worker safety, expanded metal fences can keep the entire facility secure. While most industrial uses for expanded metal are practical, the final categorization of expanded metal products is decorative. Fixtures, stands, balcony rails and more utilize metal expansion as accents as they provide an efficient, economic and aesthetically pleasing element to any setting.
Types of Expanded Metals
- Copper expanded metal is sheet or plate composed of copper or its alloys, such as brass or bronze, which has been slit and stretched simultaneously to create an open framework of solid construction.
- Expanded aluminum is the result of aluminum sheets or plates undergoing a machining process in which they are simultaneously cut and stretched to create an open grid of the silvery-white metal.
- comes with a variety of mesh patterns other than the
standard diamond shape, and may also be produced using more decorative
metals, such as copper or silver.
- Expanded metal fence is
fencing produced from expanded metal. It offers strength, safety, durability
and aesthetic qualities not found with many other types of fencing.
- Expanded metal grating is
used for walkways and platforms designed for pedestrian foot
traffic.
- Expanded metal mesh is
used when smaller openings are desired, such as in filters.
- Expanded metal products include all items made from or with components of metallic elements or alloys that have undergone a machining process known as expansion which simultaneously incises and stretches the material.
- Expanded metal screens consist of a surface of light gauge sheet metal that has been slit and stretched to create a pattern of uniform small openings.
- Expanded metal sheets are a framework of interlinked bars that create a uniform pattern of open space through the simultaneous cutting and stretching of a number of alloyed metal plates.
- Expanded steel can
be found in a number of strengths for applications varying from walkways
and fencing to corner netting for use under plaster and drywall.
- Flattened expanded metal has been cold-rolled after expansion, providing a smooth,
flat and level sheet. The metal's thickness thus will be reduced
by up to ten percent.
- has very small opening in comparison to other types
of expanded metals or mesh.
- Stainless steel expanded metal is a highly anti-corrosive sheet, mesh or grate of solid construction that is used in applications where volatile chemicals or hygienic cleaning occur.
- Titanium expanded metal is a framework of interlinked bars and uniformly patterned open spaces. Titanium is a highly valued material known for its strength and durability.
- comes directly from the press and has a raised
pattern. The strands and bonds are set at a uniform angle to the
plane of the sheet.
Expanded Metals Terms
- Custom
size expanded metal part made to customer's specifications.
- The
solid intersection of two strands of metal found in expanded metal.
- Manufactured
closed perimeter diamond.
- Expanded
metal produced as one continuous coil of the material rather than in
individual pieces.
- This
is the description of the open area formed by strands and bonds. Normally
the open area is diamond shaped.
- All
expanded metal products except grating are leveled after having been
expanded.
- Long
way of diamond or long way of opening is the dimension measured across
the sheet in a direction parallel to the largest dimension of the diamond.
- This
is the nominal distance from the mid-point of one bond to the mid-point
of the next bond measured across the SWD. Mesh is expressed in inches.
- The
total open area of a section of expanded metal. Found by calculating
two times the strand width, divided by the short way of diamond (SWD),
and then taking the inverse of the resulting number.
- Short
way of diamond or short way of opening is the dimension measured across
the sheet in a direction parallel to the smallest dimension of the diamond.
- Thickness
of base metal when in the unflattened state.
- The
dimension associated with the thickness of one strand of metal.
