Soap bubbles do not form a uniform surface. The alkaline film varies by millionths of a millimeter, so that the light in the visible range of approx. 400-720 nm is reflected at the surface of the soap bubble at different frequencies and we perceive the soap bubble with its magnificent rainbow colours.
The situation is similar with film materials. To the human eye, the film forms a homogeneous surface. A closer look under the microscope would show that the surface of the film is not homogeneous either, but varies by millionths of a millimeter.
Comparable to the colour areas of the soap bubble, these areas merge into each other and thus create varying areas of electrostatic charge. These areas can be increased during the production process or reduced by using an Enulec ESA system. As a rule, films tend to have an excess of static charges at the end of the production run. The Enulec ESA Roto-Film Pro specifically counteracts this effect with its patented technology. However, there are exceptions to the rule, e.g. when using PU-based inks with a high solvent content.
A field report
A current example from a leading European customer in the packaging industry shows how all static charges can be reduced to an absolute minimum, even with PU-varnish by using the Roto-Film Pro technology including inline measurement and EST-DC-LDS discharge. The customer had received a new rotogravure printing press and until now had always had problems with trapped static charges when printing with white PU ink on a film substrate. Suitable countermeasures adapted to the special production situation using the patented Roto-Film Pro technology enabled the optimum ESA connection to be determined in a short time and all static charges to be eliminated. The investment in this technology has significantly improved quality management, and as a result customer satisfaction has increased significantly.