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Mesh Matters

(June 2009) posted on Wed Jun 03, 2009

The level of detail you can print, the quantity of ink you lay down during the print stroke, and the ability to reproduce an image accurately and consistently are but a few of the print characteristics that are influenced by your screen. Here you


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Screen fabrics have warp threads, which are the threads that run the entire length of the roll or bolt of fabric, as well as weft threads, which are woven through the warp threads and run from one selvage edge (edge of the roll or bolt) to the other. The threads june be woven in two different ways. The most basic weave is plain weave, which follows a one-over/one-under pattern in which a weft thread alternately goes over one warp thread and under the next (Figure 1). A plain weave creates a square mesh opening and the most predictable printed-image quality. New fabrics with extremely narrow thread diameters have made it possible to manufacture a wide range of plain-weave mesh counts.

The other fabric type is twill-weave mesh. A twill weave produces a diagonal or twill line across the fabric face and is produced by weaving the weft thread over two warp threads and then under one in a repeating pattern (Figure 2). The twill weave structure is less complicated for producing high thread-count meshes because it provides greater fabric strength. However, the fabric pattern created by some twill meshes can lead to unpredictable ink deposits and moiré, so it is used much less frequently than plain-woven fabric.

After mesh is woven, it june undergo a calendering process in which the fabric is passed through a set of calendering rollers to flatten one or both sides of the fabric. This reduces both the mesh-opening size and the overall thickness of the woven fabric. Calendered mesh is used in specialized applications where a very thin, measureable ink deposit is critical.



 

Mesh by the numbers

Mesh is manufactured to metric specifications, and the woven mesh count represents the number of threads per centimeter. In the US, however, mesh fabrics are typically referenced by their nominal mesh count, which is the calculated equivalent number of threads per inch. For example, a mesh woven at 120 threads/cm has a nominal thread count of 305 threads. This is the nearest approximation of the calculated count (120 threads/cm x 2.54 cm/in. = 304.8 threads/in.).


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