Static Control & Web Cleaning Static generation – countering the phenomenon
By Iain Cameron, marketing director at Meech International T
he packaging and labelling sectors are under increased pressure to keep up with today’s
demands, resulting in faster moving production lines and machinery. The food and drink industry in particular is seeing a greater range of materials used in label and packaging production, including filmic materials that are designed to dazzle and draw the eye of the consumer. With modern production lines capable of running at upwards of 1200ft/min, static generation is inevitable and can lead to a number of issues. Poor print quality, tiny holes that appear in extruded film, and blockages in machinery equipment are all consequences of static manifestation on web surfaces. Arguably though, the main challenge in a sector that places significant concern on quality control is dust attraction; airborne particles are attracted to charged surfaces, which leads to rejected products and waste.
HOW DOES STATIC GENERATION OCCUR? Static arises when an external force causes an electrical charge to move from one material to another, leaving one positively charged and the other negatively charged. If one of the materials is conductive, it won’t hold the charge, but if the material is non- conductive the charge is unable to move across the surface. This creates a static pool of electrical charges which can attract dust and other contaminants. The presence of static will attract contamination onto the film from machine frames and the process environment, leading to high rejection rates and the disposal of tainted products. Static can also cause tension and web alignment problems during printing and rewinding processes, and even shock operators.
HOW CAN STATIC GENERATION BE COUNTERED? It is important to understand that if there is no static solution in place on high-speed converting equipment, issues relating to charged materials are likely to arise. Given the conditions in a packaging and labelling environment, preventing static generation is very difficult; however, it can be eliminated during the converting process using the correct technology. Ionising bars can ensure the material’s
surface remains void of any contamination, guaranteeing print quality is maintained and health and safety is observed. These bars contain ionisation technology, which employs high AC or “pulsed” DC to produce ionised air that neutralises the surface charges.
Ionising bars come in three forms, suiting long range, medium and short range applications. Long range systems achieve greater static control for general applications, whereas short and medium bars are more suited to target distances varying between 2 to 20 inches. Today’s static control bars have seen a
change from the AC systems of before – more efficient ionisation is now made possible through 24V integrated power supplies. What’s more, they have a stronger resilience to build-up of contamination, are easier to clean, and with their improved shockless design, are safer for operators to handle. The development of automation
technology in the area of static removal systems can allow for an even more fluid production process. Devices are available that can control up to six ionising bars at one time and offer ease of communication between connected devices through LAN or WAN networks. With this technology, operators can access their static bar performance information
on a remote device and adjust the operating settings to achieve maximum productivity and quality output. But an ionising bar alone will not combat the issue of an unclean web, which may initially pick up contaminants before going through a static control device.
WHAT’S THE MOST EFFECTIVE WAY TO CLEAN A WEB? With their ability to keep product quality at its optimum level and wastage to a minimum, web cleaners provide an ideal solution. They come in two forms – contact and non-contact. The former, Meech’s TakClean being an example, incorporates twin elastomer rollers which make contact with the full width of the web. Suitable for narrow, slower printing lines, these rollers lift and remove the contamination from the web surface. Utilising fluid dynamic principles to
deliver higher levels of cleanliness onto web based applications, non-contact web cleaning systems, such as Meech’s CyClean, are generally compact machines that are easy to integrate. They utilise powerful blowing airflows to strip the boundary layer of all dust and dirt on the web’s surface, before capturing and vacuuming the turbulent air and contaminants. With no consumables required and contamination levels not compromising the web cleaner’s function, operational costs are kept to a minimum.
PRODUCT CONSISTENCY The installation of web cleaning and static control solutions increases productivity and product consistency while reducing waste and running costs. Arriving at the right choice of system however requires an understanding of the source of contamination, the way in which static is being generated, and how it will impact on your production. Only then can you make a truly informed decision on which of the different approaches to web cleaning and static control are right for you.
umeech.com 28 November 2018
convertermag.co.uk
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