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Shedding Light on the Coating Process

(February 2008) posted on Mon Feb 04, 2008

Discover where mistakes are most likely to happen in the screen-coating process and what your screenroom staff needs to do to avoid them.

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By Gordon Roberts

Last month, we continued our journey through the often neglected but crucial stencilmaking area of the print shop. This month, we’ll attempt to throw some light on the coating part of the equation. (Please excuse the pun.)

Some of you have done your research, bought a state-ofthe- art coating machine, purchased a new exposure unit at the most recent SGIA show, purpose-built your drying chamber with its own unique dehumidifying units, and sent your staff away for extensive training, furnished generously by your favorite emulsion supplier. If this sounds familiar, I suggest you take this time to read and enjoy your latest financial statement. You will see the savings and the profitability that result from all this time and effort. For the rest of us—and from my observations, we seem to be the majority—read on for a quick wake-up call that will spark new life into your entire screenproduction operation, remove frustration, add hours to your production day, and improve the quality and repeatability of the images you produce.

I am amazed by the number of people I meet who create stencils for a living and have little or no idea about exactly how the process works. You don’t have to be a chemistry genius to create stencils, but I strongly believe that you do need to understand the basics of the stencilmaking process. Take the time to learn what is actually going on at the molecular level when you shine a UV light source on a photochemically coated piece of fabric. Ask your supplier to explain the theory. If it doesn’t make sense to you, make him or her explain it again and again until it does make sense to you. Check back issues of Screen Printing magazine for some great articles written on this subject. Most importantly, don’t assume that the information is too technical for you. It’s actually very simple once you take the time to learn the basics. Let’s move on to some basic truths and see if we can’t make small changes in your stencil-prep area that will yield huge gains for your screenmaking process as a whole.


First basic truth: Never use a screen that is not fully prepared for coating


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