Screen mesh warp direction

The screen mesh is manufactured by weaving stainless steel wires to form a long sheet. The direction along the length of the sheet is referred to as the "warp" direction, whereas the direction across the width of the sheet is referred to as the "weft" direction. The vast majority of meshes used in thick-film screen printing are woven in the so-called plain weave pattern, as shown in Figure 5.4, formed by routing one wire over and under only one wire at... 

Twill weave n. A cloth weave in which the warp yarn runs alternately over two fill yarns and under one fill yarn. The twos and ones may be staggered with adjacent or r -ularly spaced warp yarns to produce a di -onal effect. In Dutch twill, wires of different sizes are used to produce a very dense screen with tortuous passages (light does not pass directly through) and an effective mesh number of 1200 or more. Twilled screens... 

One of the most important parameters of the screen is the mesh count, or the number of wires per imit length. In general, the mesh count is the same for both the warp and weft directions, as is the wire size. In practice, tiie mesh count may vary from 80 wires per inch for coarse screening, such as solder paste, to 400 wires per inch for fine-line printing. 

Stainless steels are complex mixtures of various components. During screen SEM analysis, qualitative composition measurements of each of the three meshes were made using Energy Dispersive X-Ray Microanalysis (EDA)Q on both warp and shute wires. For all three screens, analysis showed that both wires were comprised of similar steel components, and that the ratios of metal components of the porous LAD screen, such as Carbon, Oxygen, Nickel (Ni), and Iron, were in direct proportion to a bulk 304SS sample, although not shown here. 

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