Flexible packaging manufacturers are under continuous pressure to produce large quantities of high-quality product—and this is expected to continue into the coming years.
A report by Smithers that investigated the growth of the flexible packaging market suggests flexible plastic, paper and foil packaging will continue to see a steady rise in demand across the next five years. This comes after a sustained period of increased awareness of and a demand for greater sustainability, and disruption to supply chains caused by the COVID-19 pandemic. The report also suggests that overall worldwide consumption will increase in 2021, with the projected value at 31.5 million tons.
With an increase in demand for materials and products comes an increase in pressure on manufacturers to deliver them—in good time and to high quality. But busy production environments are a haven for static generation, dust and dirt, and the combination of these issues causes serious problems in the form of quality control, machinery breakdowns and excessive waste. Fortunately, highly sophisticated technology in the form of static control and web cleaning devices has been devised by technically advanced companies who are well equipped to understand how static arises and the consequences of such a phenomenon.
Static Prevails
Static charges can occur via friction, separation or induction. In many converter environments, fast-moving machinery and webs are commonplace and are prime areas for static charges to be generated—for example, via a web being unwound at a fast rate (separation) or running over nip rollers (friction). The generation of static draws nearby airborne particles to the surface of the web material, compromising the hygiene levels of the material and severely impacting the appearance of the finished product. Static itself can also lead to print work appearing faded due to its impact at the printing stage.
With the flexible packaging industry due to face such high demand, the threat of unwanted static is significant. It is therefore important to understand how contamination to packaging materials occurs and its impact on the converting process. But static charges are not the only phenomenon that leads to debris being drawn toward the surface of a web. When the web is moving at high speed, a natural boundary layer is created as it drags along ambient air. This boundary layer, which thickens with increasing speed, can cause debris to become trapped within or beneath the surface of the layer.
There is heavy scrutiny of operations at production and supply level. Hygiene and health and safety are paramount. Sectors that work with food and medical equipment in particular have stringent laws on hygiene and any packaging or product that is found to be unclean will be discarded, increasing wastage and possibly causing delays. Investing in solutions to counter these issues is vital to production and business profitability.
Static Control
The most effective way of removing the threat of static charges is to install static control in the form of ionizing bars onto converting equipment, just prior to and after the point where static charges most commonly occur. This can be determined with help from an expert in the static control field, who will have the sophisticated technology to detect the severity of the charge across different areas of the converting process.
“The most effective way of removing the threat of static charges is to install static control in the form of ionizing bars onto converting equipment, just prior to and after the point where static charges most commonly occur.”
By neutralizing the static charges, static control can significantly reduce the risk of static charges and contaminants being attracted to the web’s surface. This technology often comes in the form of a DC ionizing bar, which is typically placed immediately before a web cleaner on a production line. These bars direct positive and negative ions of electricity at the web’s surface, which neutralize any charges present.
Modern ionization technology, such as Meech’s Hyperion range of DC static control bars, are available in formats that suit short-, medium- and long-range applications. The bars found in this range are ideal for today’s modern, fast-paced production environments and are engineered to include monitoring technology as well as control over output voltage, frequency and balance.
Befitting an age of increasingly advanced, highly automated smart technology and Industry 4.0 solutions, Meech’s SmartControl enables operators to see the performance information of multiple static control devices at once and control them remotely via a mobile phone, tablet, touchscreen or PLC. These devices can also be connected to static bar controllers, which automatically alter the levels of ionization supplied from the static bar.
While static control offers an effective solution to combating static, contamination must be countered with additional equipment.
Web Cleaning
For optimum web appearance and function, any static control devices should be paired with a web cleaner. With product cleanliness of utmost importance to manufacturers, web cleaners are a cost-effective way of maintaining high-quality products while preventing wastage. Given the environment that flexographic printers operate in, web cleaners are vital, as all webs present on flexographic presses will have some degree of contamination on their surface. Paper-based webs have higher surface dust contamination, whereas filmic materials, which generally possess cleaner surfaces at the beginning of the flexographic process, can be contaminated by statically drawn airborne and environmental pollutants.
If these contaminants are not removed, or at least reduced to a minimum by a web cleaning system, then they will immediately find their way onto printing plates, inking systems and anilox rolls. This can lead to a myriad of issues, including reduced print quality, which increases overall downtime and wastage.
By removing contamination, an inevitable byproduct of high-speed webs, effective web cleaning systems, working in tandem with static control, can increase productivity by reducing maintenance downtime and minimizing the waste caused by sub-quality product.
Web cleaners come in two different forms: contact and non-contact. Contact systems, such as Meech’s TakClean, are suitable for narrower, slower lines. They incorporate elastomer contact cleaning rollers and perforated adhesive rolls which pick up and remove contamination from the web’s surface. While highly effective at removing low to moderately contaminated web materials, the adhesive rolls require changing and are therefore not ideal for highly saturated webs.
Ideal for a wide variety of applications, non-contact solutions utilize airflow to clean webs. Providing exceptional contamination removal for a wide variety of applications, Meech’s CyClean is an advanced system capable of handling virtually any substrate. It provides comprehensive decontamination and will remove particles as small as 0.3-μm. With more materials being developed for converters to process than ever before, non-contact systems provide a long-term, future-proof solution for converters.
The development of flexographic materials and products and the varying applications that are coming to market, coupled with the increased demand this sector is set to face within the next few years, means printers and packagers must find ways to keep up with order volumes and also be quick to adapt to change. The installation of static control and web cleaning solutions can increase the productivity of any production line, and ensure products are processed to a consistently high quality. The most advanced systems are also highly flexible, helping to future-proof businesses.
It should be noted that every business and its requirements are different. Assessments should be performed that can help determine the levels of static and contamination that are currently being generated on the line—only then can the appropriate equipment be selected.
About the Author
Matt has been a contributing writer for such trade magazines as FLEXO Magazine, Flexible Packaging, Label & Narrow Web, Paper Film and Foil, Screen Printing Magazine, Converting Solutions Magazine and Medical Design & Diagnostics.