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2010
Conference Paper
Titel
Powder coating with advanced electrostatic fluidized bed technique using pulsed corona charging
Abstract
There are many and good reasons why powder coating is a popular coating process for a lot of industrial products: the wide range of design possibilities; robust surface finish; and the total avoidance of polluting solvents, to name but three. In conventional powder coating installations spray guns are used for powder application on the workpieces. This requires voluminous spray booths and powder recovery systems. Thus conventional powder coating technique causes high consumption of compressed air and of energy for the exhaust air as well as high costs for maintenance. In view of this, the Fraunhofer IPA has designed the "TransApp"-powder coating technique, which operates without spray guns and therefore is very compact, highly energy-efficient, and has low operating costs. The new technique makes use of the well-known electrostatic fluidized bed principle. Its previous process limitations such as poor application uniformity and poor decorative surface quality have been overcome by using computer simulation as well as by adopting innovative technologies to regulate the electric field. In this connection, using pulsed corona charging has been a very successful approach. The periodical interruption of the electric field and of the generation of ions turned out to be an effective method to minimize the unwanted parasitic electrostatic effects like insufficient coating of edge zones and Faraday cages.