Plastics Decorating - January/February 2008 - (Page 38) SPECIAL FOCUS continued from page 37 • Hard pads are most suitable for textured surfaces. They also can be used when printing an image in a recessed area next to a raised surface where the pad will have to roll over the ‘step’. • Hard pads also can be utilized in a pad ‘nest’ or matrix, when a single machine must be fit with numerous pads that are spaced with small gaps between them (for example, when printing computer keyboards). • Use softer pads when printing heavily-contoured surfaces or fragile items. • A softer pad must be used if the power of the machine can’t compress the pad sufficiently to achieve a satisfactory rolling action. • Avoid using pads of different hardnesses on the same application, or the thickness of the ink deposit will vary on the substrate. This is particularly true when dealing with a pad matrix. the initial silicone oil removal. But excessive use of such a strong solvent damages the pad and shortens its life. Pads with a ‘ready to use’ finish virtually eliminate the need to matte the pad. With these pads, the base rubber material is very close to the desired pad hardness, so the manufacturer adds much less silicone oil, if any. After matting the pad (if necessary), the only other step that must be taken prior to production is to wipe the pad gently with an alcohol-based pad cleaning fluid. This removes any free silicone oil that can sometimes leach out of the pad. However, once the pad has been used, the best way to remove solid debris, dried ink, and dust is with a quality brown packaging adhesive tape. By following this simple procedure, you will improve your print quality, reduce downtime, and prolong the life of the pad. Some pad suppliers provide ‘rejuvenating oil’. Basically, this is a silicone spray that can be applied to the pad surface when it becomes dry due to the removal of silicone oil by aggressive thinners. It can help prolong pad life, but spraying silicone spray anywhere near a surface that has to be decorated is a recipe for disaster. Because of the potential problems, using such oils is not recommended. We have come across two extreme cases of pad abuse. The first company soaks its new pads in a solvent tank for four hours prior continued on page 40 Surface Finish Throughout the pad printing industry, the custom practice among pad manufacturers is to furnish pads with a high gloss finish. Users have had to ‘matte’ the pad surface - that is, remove the excess silicone oil that creates the glossy appearance - to enable the pad to pick up and transfer ink during the printing process. Typically, pad printers will use a strong solvent such as a fast thinner for Taber Industries www.taberindustries.com 38 http://www.taberindustries.com http://www.taberindustries.com
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