November 2019 Roundtable on Static Control
How does static manifest itself in printing?
Coldren: High static levels negatively impact quality, productivity and safety and can occur with all varieties of presses and printers. Examples of problems caused by high static levels include: contamination adhering to the substrate resulting in problems with ink adhesion and necessitating frequent cleaning of print heads, misfeeds, registration issues and jams. High static charges can cause static discharge events (arcing) interfering with sensitive electronic devices and/or causing uncomfortable and dangerous operator shocks.
What are the major causes of static in converting operations?
Coldren: Contact and separation of insulative surfaces or an insulator with a grounded surface will create a static charge. The magnitude of the static charge will vary by material, process, process speed, web tension and humidity. Operations like winding, transport, trimming, coating, slitting, sealing and wrapping usually require active static elimination to reach line speed and production goals while maintaining a safe work environment.
What is the difference between passive and active static control?
Coldren: Capability. At Simco-Ion, we have made both for over 70 years, but the differences today are more apparent than ever. Today’s active ionizers, with their monitoring, communication and Industry 4.0 capabilities, have evolved far beyond what is possible with passive ionization. Most converters are familiar with passive ionizers like anti-static tinsel, static string and anti-static brushes. They intermittently produce ions under only very specific conditions, the most important being a high incoming charge level. Without the high incoming charge level, proper installation and mounting, their performance is marginal at best, with little or no ionization.
By contrast, an active ionizer, like a static bar, ionizing nozzle or ionizing blower, will utilize a power source, and thus be capable of producing ions continuously, regardless of incoming charge levels or proximity to the target. Active ionizers must also be properly installed and maintained, but unlike their passive counterparts, they are effective at reducing all incoming charge levels. Active systems have seen significant advances in the last few years and current generation active systems can adjust, display and record ionizer status, ionizer output and in-process static charge levels. Faced with the quality, safety and general production issues that static charge can create, active systems can provide the intelligence necessary to manage and record performance. This, in turn, keeps production running as quickly and safely as possible. Passive systems cannot do this.
Does static have any benefit in the production of flexible packaging?
Coldren: Yes, adding static to a production process, often referred to as electrostatic charging, or static pinning, has numerous applications for converters. Static charge can be used to compress and temporarily bind two surfaces together. For example, pinning a laminate or protective film onto another insulative surface, holding the edge of a finished roll in place to eliminate the use of adhesive and maximize product placement by compressing insulative products inside the packaging. Electrostatic pinning has been successfully used for many years to improve the speed and quality of In Mold Labeling (IML) by holding the label in place in the injection molding tool. IML charging applicators continue to advance technologically, with today’s systems being able to give feedback when the label has reached its maximum charge and when the charge on the core has been reduced to a safe level for retraction.
How does the control of static affect productivity, quality and safety?
Coldren: A properly implemented static control system will improve productivity, quality and safety. Static control ties directly to how fast the process can be run, how safely the line is operated and the quality of the delivered product. For example, static control eliminates one of the greatest barriers to achieving high quality — contamination. Active static systems can eliminate charged substrates preventing dust from clinging to the surface. If this contamination on substrate materials isn’t eliminated or prevented, the material is compromised throughout the entire process. However, if static control alone is not enough to provide a clean substrate then we recommend removing and capturing the contaminant. Teknek offers the best possible result via contact cleaning. In situations where we cannot deploy the Teknek, we offer newly designed contact and non-contact vacuum systems.
What new features or technologies are being introduced to today’s static control equipment?
Coldren: More and more intelligence. Many converting customers feel it is no longer good enough to mount a static eliminator and assume it is working. They can’t risk waiting for an adverse outcome to find out the ionizer has not been working for some period of time. Customers have come to rely on today’s newest systems that monitor ionization, record data and signal potential problems. The future will continue this trend with more communication and data collection. Systems of tomorrow may focus on predictive elements that enable a potential problem to be addressed before it becomes an actual problem that impacts production. These types of intelligent products will communicate in real time, satisfying customer requirements for Industry 4.0 and demands of the future.