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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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Thread diameter refers to the thickness of the threads used to weave the mesh (Figure 3). Thread diameters very widely, from thick yarns are used to weave coarse meshes (e.g., 24-thread/in. fabrics with 250-micron thread diameter) to thin yarns used to weave high mesh counts with workable mesh openings (e.g., 305 threads/in. with 40-micron thread diameter).

The mesh opening is the open area that is bounded on four sides by woven threads. The width of a mesh opening is measured in microns. Technical diagrams of mesh typically depict the open as perfectly square. But achieving a square opening is impossible when using rounded threads. The weaving and finishing processes create mesh openings that are less regular than a perfect square. Mesh openings in plain-weave fabrics tend to be more consistent than those in twill weaves. The size of the openings is an important parameter to consider when determining printability with certain inks, especially those that contain large and coarse pigments or metallic particles.

The open area of a mesh fabric is a percentage value that represents the area of the mesh covered by mesh openings versus thread. The percentage is generally calculated based on one square meter of the fabric. Two fabrics with differing thread diameters can have the same mesh count, but they will have different percentages of open area. This is important to consider when selecting fabric for a job with specific ink-deposit requirements.

For example, a mesh with 305 threads/in. and 40-micron thread diameter has an open area of 25%, while a mesh with 305 threads/in. and 35-micron thread diameter has an open area of 33% . Comparing the fabrics reveals that a reduction in thread diameter of only 5 microns (12.5%) results in an increase in open area of 32%. For a job requiring a heavier ink deposit, the fabric with 35-micron threads is clearly the better choice.


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