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| Posted on 3/13/06 at 07:40 PM | |
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Hi Tula, This type of system has its disadvantages. It is a multi point light source, and because of this you will not be able to get very highly detailed images. A single point light source with a higher-powered metal halide lamp is the way to go. The florescent bulbs don’t have the proper wavelengths to cure the emulsion in a fast or complete way if you are using a dual cure emulsion. You need a pure photopolymer or, SBQ emulsion that dose not need the higher powered light sources to cure. With the multi point light source you get excessive under cutting of the stencil. If you are using white colour mesh, this problem will be compounded. The white mesh will speed exposure times, but will cause under cutting also. This might be the reason that you cannot get the detail to wash out of the fully cured emulsion. The light scatter is too great. If your images that you want to print are not too detailed, then don’t worry ABOUT WHAT DID NOT WASH OUT OF YOUR EXPOSURE CACULATOR!! Just worry about getting a fully cured stencil. This is the info on your emulsion. Follow the link www.wmplasticsinc.com/PDF/Emulsion/murak/MURAKAMI_photo_cure_blu.pdf Follow this checklist. 1- what mesh count and mesh colour are you using... white is good for fast exposure times, dyed is good for detail. 2- does your emulsion match the spectral output of your light source. (300 to 400 nanometers for SBQ) (365 to 420 nanometers for dual cure) 3- what kind of coating trough to you have. What coating techniques are you using? 4- do you have good vacuum pressure before Turning the light on. 5- what do you have to wash out the images with. A pressure washer with at least 500 PSI is recommended @ a 10 to 12 inch distance to get good wash out. Just some things to think about. I hope this helps I would start off with a 20 min exposure, on a 155, micron white mesh, coated 2+2, with a round edge coater. And see where you need to go from there with the calculator. I hope this helps. | ||
  
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