Filtration and separation technologies are critical to many applications that cover a broad cross-section of consumer and industrial products. There are literally millions of uses for filtration and separation that touch our day-to-day lives.
Comparing three forms of metals’ properties and qualities
When it comes to filtration methods that require strength, heat-resistance and durability, three forms of metal make up the vast majority of solutions for these requirements: perforated metal, Expanded Metal and wire mesh. Each type offers effective filtration. However, there are different properties and qualities of each that should be considered when determining which is optimal for an application.
Perforated metal is metal that has had holes or openings punched through it, either via an all-across press or another method such as CNC punching or laser cutting. The unique qualities of perforated metal for filtration or separation include:
Versatility: Perforated metal offers the greatest overall versatility in pattern, shape, material type and hole gauge among the three materials discussed here. When the amount of open area (the hole that allows the passage of air, light, liquids, etc.) is critical to the efficient operation of the application, perforated metal can provide the greatest control of open area.
Strength: While all three methods offer high structural strength, perforated metal is the only method that can be freestanding. This is because perforated metal can be manufactured with nonperforated borders at its outer edges, providing greater stability. Expanded metal and wire mesh must be attached to stabilizing frames.
Weight: Since material is removed during the manufacturing process, perforated metal will weigh much less than expanded metal when using comparative materials. Further, it has great strength-to-weight ratio properties, meaning the weight is lowered but the strength is not significantly compromised. This is an important distinction for weight-sensitive applications.
Expanded metal is produced by cutting a pattern of slits in metal coil, then stretching (or expanding) it so that the slits become diamond-shaped holes. Expanded metal is typically a thinner material than the other methods described here due to the nature of the process. However, this metal type offers a number of advantages and unique properties.
Configuration options: Although the distinctive diamond-shaped pattern of expanded metal cannot be changed, expanded metal pieces can be configured in different ways. Standard expanded metal retains a 3-D raised, slightly twisted configuration of the piece after the stretching process. The metal can be further processed to flatten any strands of the diamond configuration that may be raised or at an angle.
Strength: The one-piece construction, along with the configuration of the diamond shapes, provides a great deal of structural integrity. Expanded metal is often used for industrial uses such as flooring, steps, walls and gates for this reason.
Wire mesh can be of woven (interlocked) or welded construction. In either case, wire mesh consists of strands of metal wire fastened together to form a mesh sheet. Some unique properties of wire mesh include:
Flexibility: Wire mesh is also sometimes called wire cloth, and it can be woven in such a way that it provides the same flexibility of cloth. For applications where a non-rigid construction is required, with the same filtration properties of metal, wire mesh is often the right choice.
Gauge and construction versatility: Wire mesh can be manufactured with large openings (for applications such as fences) or nearly invisible openings (when higher rates of filtration are required). In addition, wire mesh offers some flexibility in opening shapes, though not as many options as perforated metal.
While each of these metals have unique strengths, it’s important to understand the specific requirements of the application to determine which will work best for you. If you are working on a project and are unsure of what type of metal to use, consider reaching out to a metal manufacturer to consult with during the selection process.
Jake Holeva is business development manager at Hendrick Manufacturing, Carbondale, Pa. To learn more, visit www.hendrickcorp.com or call (570) 267-3814.
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