Awards & Engraving

March '16

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20 • A&E MARCH 2016 LASER ENGRAVING APPLICATIONS you are also marking the glass. The wet newspaper acts as a coolant, helping dis- sipate the heat, which results in minimal glass fracturing. On larger areas, you may have to establish a method of keeping the newspaper wet while laser engraving as the exhaust fan can quickly dry it out. 80 PERCENT IS BETTER THAN 100 PERCENT? Another technique is to laser glass using an 80 percent screen. Instead of making your graphics 100 percent black, tell your laser that the graphics are 80 per- cent black or extremely dark gray. If you were to use a microscope, you would see that there is a fine dot pattern as opposed to a solid marking. Remember, the problem with glass fracturing is due to the heat. By using a 75 to 90 percent screen, the glass is not heated as much and hence, does not fracture. You are left with a smooth pattern with minimal shards of glass. Another related technique is to lower your DPI, which allows more space between the laser passes and helps mini- mize the fracturing process. I have heard of laser users applying a film of dish soap to help dissipate the heat when laser engraving glass. D av i d S c h wa r t z , H o o s i e r L a s e r Graphics, recommends running your laser out of focus. You may recall Schwartz from previous articles—he is also the master- mind behind the Rack Star, a low contact modular cutting table system using var- ious "v-blocks" and risers to securely hold unusually shaped objects in your laser bed. Schwartz, who has vast experience with laser engraving glass, offered this tip: "I focus (my laser) about a third off center." He also suggests that all users do a matrix test to examine best results when running the laser out of focus. While testing and finding that optimal focal point, Schwartz suggests you start at your usual focal point and deviate 1/16 inch closer until you find the best result. He also recommends that you do this test with every type of focal lens you own, as each focal lens will have its own unique characteristics. "I use a 2.5-inch lens on all my glass- ware," says Schwartz. Because he does not use a rotary attachment when laser engraving glassware, he states that "the (2.5-inch) lens overlaps and gives you more room to go around the arch of the glass." Sandblasting provides a quality look with clean and crisp graphics. Shown here is a close-up of sandblasted graphics. Dave Schwartz, Hoosier Laser Graphics, stands in front of his Laser Rack table system while removing any shards using the 3M Scotch Brite Clean and Finish pads.

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