Non-electrically conductive substrates form a large part of the engineered coated products in the market place, such as glass panels, plastic decorative components, polymeric flexible webs, etc. Many of these substrates offer a low cost raw material, and require surface engineering in large production manufacturing processes in order to bring a cost effective functionality. Many of the vacuum coating technology processes involve coating of such non-electrically conductive materials. All functional coating require a minimum level of adhesion and that is typically achieved by substrate preparation before the functional coating gets deposited. In electrically conductive substrate the negative biasing of the substrates would enhance the ion cleaning of the substrate by increasing the bombardment efficiency of positive ions generated in the plasma over the negatively biased substrate. In non-electrically conductive substrates that bias is reduced to the self-bias which occurs as the elements are immersed in the vacuum plasma environment. Sometimes that level of bombardment is not sufficient in order to bring adequate cleaning and preparation of the substrate/coating interface and in most cases it cannot bring consistency of performance during the whole manufacturing campaign. For those cases then active cleaning methods are required. Plasma treater is a general term used for substrate cleaning, preparation and conditioner before a functional coating is being deposited over a substrate. Plasma Treaters are specially important when the substrate is electrically non-conductive. This presentation will explore the ways in which these plasma treaters are being used and some of the challenges ahead and aspects that would require a higher degree of control on plasma treatment processes.
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