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| Posted on 9/18/08 at 05:48 PM | |
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The most common cause of stencil breakdown is underexposure. The invisible UV energy has to move all the way through the stencil to the inside of the screen, where the water based ink and squeegee rub and smash it over and over. Lacquer thinner will help breakdown lacquer based inks, but will have little effect when cleaning water based ink. The simplest exposure hardness test is to use a Stouffer 21 Step Sensitivity Guide on every stencil you make for the rest of your life. You have spent way too much time guessing. Get a Stouffer 21 Step Sensitivity Guide. US$7.00 to US$ 12.00 depending where you buy it.  It is a small film positive with pure black on one end, clear on the other and 21 steps in between. You make one exposure and simulate 21 different exposures. You will have instant visual feedback on how hard your stencil is. Aim for a solid step 7.  http://www.ulano.com/FAQ/FAQexposure.htm#Q1 [Edited on 9/18/08 by richardgreaves] ____________________ Richard Greaves, ASPT Ulano Corp. New York Technical Services 718-943-1338 direct | |
  
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