By Stewart Gordon Smith, Business Development Manager (Meech International)

The elimination of static charges should be a fundamental part of the quality control measures adopted in flexible packaging. Cleanliness is a critical issue in a wide number of industries – especially food, medical and pharmaceutical – with customer demands constantly increasing the required standards. The manufacturers that fail to meet these standards risk losing out to more pre-emptive competitors in a progressively driven market.

With no static control solution in place during production, the more issues the charged material is likely to cause. First of all, the presence of static will attract contamination onto the film from machine frames and from the process environment. This can lead to the disposal of tainted products, as well as high rejection rates that can have an effect on customer loyalty. Static can also cause tension and web alignment problems during printing and rewinding processes. Other issues instead raise a number of health and safety issues, such as operator shocks or, where solvent based inks are adopted, the risk of ignition of flammable gasses and substances.

In the flexible packaging process, filmic substrates require corona treatment to allow the ink to adhere to the material’s surface. However, the treatment is likely to produce multiple electrostatic charges as a result of the creation of the curtain of corona plasma, which is generated by applying high voltage to a sharp-tipped electrode.

Blown/cast film will produce electrostatic charges on the material’s surface as the product cools to ambient temperature. When the corona treatment is applied, the static charges are magnified as the material passes through the high voltage plasma field. These charges can result in an increase in web tension, as the material tries to bond to path rollers and nip drive rollers, further adding to the charges present on the film. The last point of generation occurs when the film is wound into rolls, with each stratum of film adding another layer of statically charged material, as the roll increases in dimension.

The prevention and elimination of these charges can be easily achieved by installing an ionising bar (also referred to as an anti-static system) that will ensure the material’s surface remains void of any contamination, ensuring print quality is maintained and health & safety is observed.

Meech’s Hyperion range of ionising bars is designed to provide first-rate static control solutions even under the most extreme operating requirements. With the need for flexibility to control charges on high speed process lines and the requirement to work over long range, the Meech Hyperion bars can also provide closed loop automated monitoring. During the rewinding of material the performance of a Hyperion bar can be optimised, using distance or feedback monitoring options, to ensure consistent static control is maintained at all times.