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Rationalizing Screen-Fabric Selection

(October 2001) posted on Fri Oct 19, 2001

Fine meshes and tonal reproduction capabilities with UV inks


By Andr

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If I were a newcomer to screen printing and began looking at the catalogs from various mesh manufacturers, I would probably feel like turning to another profession. Faced with a selection of more than 200 different mesh types and counts, I would be compelled to find a way to narrow the field. Of course, after I learned the basics of the process, I would be able to quickly select the right type of screen fabric, because multifilament fabrics are things of the past and nylon is not stable enough for close tolerance printing. I might also know that high-modulus fabrics are the current trend. This would narrow down the selection considerably, but I would still be faced with a catalog of about 50 products, in various weaves, mesh counts, and thread diameters. The task of choosing the right mesh would still be too big for a beginner like me. In reality, do we really need so many mesh counts? This is an important question, and I sometimes wonder whether mesh manufacturers--ourselves included--aren't masochistic to be producing so many mesh varieties. We will explore the answer to this question and analyze the possibility of rationalizing the vast number of screen fabrics to what is really necessary. Throughout this discussion, we'll focus our attention on fine meshes and their tonal reproduction capabilities with UV ink systems. Why are there so many grades of mesh? Blame the versatility of the screen-printing process. In the days of silk and multifilament screen fabrics, the limited availability of different thread diameters kept the range restricted. The screen process was, however, quickly recognized for its versatility, and, as the increasing number of applications became more demanding, there arose a need for higher-performance fabrics. Monofilament yarns were greeted with open arms because they enhanced the capabilities of the screen-printing process. As ink manufacturers developed new products that addressed the needs of the market, mesh manufacturers followed suit, making fabrics that optimized the performance of the new inks. While screen printing grew into a viable commercial and industrial manufacturing process, product specialties, and the fabrics used to print them began to vary from country to country. One country might specialize in industrial textile printing. Poster printing would be dominant in another. And within specific types of printing, different countries would adopt their own "standard" grades of screen fabrics. So, on one side of an ocean, mesh count X became the standard for a particular job, while on the other side, mesh count Y was being used for exactly the same application. Mesh manufacturers continued to produce an increasing range of products to satisfy their global markets. Yarn manufacturers began extruding finer threads and weavers became more daring, weaving mesh counts that would have been unthinkable 20 years ago. The development of new screen fabrics contributed to the growth of the role of screen printing in so many industries. And today, the screen printer is spoiled for choice.

Table 1 Comparison of Fine Mesh Characteristics
Mesh count
(per inch)
Nominal
thread
diameter
(microns)
Weave type % Open area Fabric
thickness
(microns)
Theoretical
ink volume
(cm3 / m2)
355 27 PW 36 42 15 355 31 PW 28 47 13 355 34 TW 20 60 12 355 34 PW 16 58 9 390 27 PW 27 44 12 390 31 PW 20 49 10 390 34 TW 17 63 11 390 34 PW 13 56 7 420 27 PW 25 46 12 420 31 TW 24 60 14 420 31 PW 17 49 8 420 34 TW 16 62 10 460 27 PW 18 43 7.5 460 31 TW 17 56 9.5 508 31 TW 13 65 8.5

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