Introduction
Component Supply’s stock of nylon and polyester filter mesh is a versatile material used in multiple industries and various applications. To assist researchers and product designers in choosing the best mesh for their applications, we want to define and explain the different properties of our mesh and how they impact each other.
There are seven major attributes of mesh: 1) mesh opening, 2) open area, 3) mesh count, 4) thread diameter, 5) weight, 6) thickness and 7) air permeability. At Component Supply, we don’t list weight, thickness or air permeability in our product information because, unlike the first four specifications, these three are not typically relevant in determining mesh use in most applications. However, to give you a full picture of mesh properties, we will provide a simple definition for those terms.
Mesh Attributes
1) Mesh Opening refers to the actual size of the opening. In the charts on our site, this is measured in microns. Mesh opening is typically the most critical attribute because it determines the size of the particles it will capture and the size of the particles it allows to pass through. This attribute is specified in microns, a metric measurement equaling one thousandth of a millimeter.
2) Open area indicates the percentage of a specified area that is open. Open area can help determine what flow restrictions might occur because of the filter. If we take a square piece of mesh screening that is exactly one inch by one inch and move all the lateral and horizontal fibers (warp and weft – we will cover this in another post or video) up and to one side we will be left with some part of the square that is solid (covered by the threads) and some part that is now open. With a mesh that has a 25% open area, the square inch will be segmented into four parts, three (75%) will be covered by the threads and one (25%) will be open.
3) Mesh count is the number of threads in a linear inch and is fairly easy to determine. For example, if you were to lay out a piece of mesh and place a ruler on top, then count the horizontal threads from the beginning of the ruler to the one-inch mark that would give you the mesh count. While this is a simple task for mesh sizes like 1000 microns, which has 19 threads per inch, it is daunting or near impossible for some of the smaller mesh sizes. For mesh sizes down to about 200 microns you can count, or at least count one quarter of an inch and multiply. For sizes much smaller than that, it becomes difficult without both magnification and some patience.
4) Thread diameter is the diameter of the thread measured in microns.
5) Weight is the weight of the material typically measured in ounces per square inch.
6) Thickness is the overall thickness of the mesh and measured in microns.
7) Air permeability measures the rate of air flow passing perpendicularly through the mesh and, for our mesh, is measured liters (l)/square meter (sq. m.)/second (s).
The Relationship between Mesh Attributes
When selecting the appropriate mesh for an application it is important to know how these attributes are related. Let’s use an example of mesh that has a 500-micron mesh opening, a 50% open area, a thread count of 20, and a thread diameter of 250 microns. If we were to change just one of these attributes, it would completely alter the product you’d be using. For example, if we decreased the thread diameter but left the mesh count constant, we would wind up with a larger mesh opening and open area. If we needed to capture smaller particles with a smaller mesh size but wanted a similar open area for flow restriction reasons, you could find a mesh that has the same thread diameter and a higher mesh count, or you could find a mesh that has an increased thread diameter and keep the thread count constant.
Conclusion
Understanding the attributes of mesh filtration and separation materials and how they relate, makes selecting the correct mesh for a specific application less daunting. That being said, configurations of “standard” mesh configurations are largely determined by industries larger than laboratory sciences or medical device. Mesh is woven on looms that produce as much as 10,000 meters at a time, so only very large filtration and screen printing applications get to “choose” the combination of specs they want. While there may be other sizes, and we encourage you to ask about them, the specifications on our site represent most of what is available. With a fresh understanding of the mesh specs, you can purchase based on characteristics most relevant to your application.
