Industry Q&A - Economy, pursuit of excellence shape today's extrusion lines
Q: Recent developments in film extrusion, including internal bubble cooling (IBC) and gauge control, have improved the quality of blown film. How do advancements available now support the push for higher output while maintaining or improving product quality?
A: From an equipment supplier’s point of view, the quality of the film being made should never be compromised to achieve higher output. With recent developments in IBC and air ring design and configurations, higher output can easily be achieved while actually increasing quality. But it’s not just cooling that needs to be addressed-the rest of the line has to perform as well.
Having the best haul-off in the industry allows Kiefel customers to keep the film at the highest quality level, even after going through the collapsing and oscillation process. Building rolls need to have-and maintain-the proper tension throughout the winding process and the slitting capabilities must not be a weak link in the process. The entire system needs to be controlled by a robust control system that can keep all aspects of the process in check. This is critical to each production run and to the repeatability of each run.
Q: What new features or technologies does extrusion equipment offer that guarantees converters versatility in their film manufacturing operations?
A: In recent years, we’ve seen die heights come down dramatically. This shortening of the die equates to shorter residence time and shorter melt flow paths, plus it reduces the likelihood of material degradation. Now that 9-layer dies are becoming more common, this low profile design will allow converters to run even the most sensitive materials without damaging the polymer. With more common 3-, 5- and 7-layer dies, this is an even bigger benefit.
Another technology for versatility is modular equipment design. The ability to modify or change the configuration of a line as a converter’s business changes is a must. Kiefel has done numerous upgrades to existing blown film lines simply by adding components. Our Kirion C control system automatically recognizes the hardware changes without major updates to the existing software or computer system.
Q: What trends do you think are shaping innovations in extrusion technology and why are these important?
A: Certainly there are some major social influences that are shaping the way we look at our equipment design. Perhaps the biggest influence at the moment is the economy. Though the industry may be turning a corner, funding for new equipment is not as readily available as in the past. In response, Kiefel developed the e.co.s line of Kirion extrusion systems, a standardized line configuration based on the same proven technology and components that make up our high-end custom built lines. The standardization of the entire system allows us to sell this line for considerably less than other lines with similar features.
Another strong influence is the green movement. With plastic coming under increasingly stronger environmental pressures, we design our lines to feature the highest efficiencies possible. We are also designing our lines to process the latest biodegradable resins.
Web Exclusive ContentQ: What challenges do new resins, including bio-based and other performance products, present to extrusion equipment and how are you solving them?
A: Resin companies are developing new and dedicated resins that are product-specific and extrusion equipment suppliers need to develop equipment that processes these new polymers without sacrificing output or quality. From new screw and die designs, to advanced cooling systems, and all the way through to the winder, each component in the lines needs to be considered to provide the best possible system to our customers. Bio-based resins create even more of a challenge as they process much cooler than traditional polymers and have a tendency to wrinkle easier.
Q: Looking ahead, what trends in flexible packaging converting do you see having the greatest influence on extrusion equipment and why?
A: When we design new equipment, we are always asking what the next step in the process is: How will the film be used? There are a couple of trends that stand out, especially in our current economic environment. Just like our customers making film, converters want higher speeds on their equipment. This sounds easy enough, but in order for a printing press, laminator or a bag machine to run faster, the film has to be perfect. That means the gauge tolerances must be extremely tight and the film must be very flat.
However, one step that often gets overlooked is how the bubble is collapsed. This process is critical to having a film that can run at very high speeds on a press or a laminator. The Kirion T haul off is designed with long collapsing frames with a unique brush roller system that moves with the film, reducing the stresses that collapsing inherently induces and minimizing or eliminating wrinkles. The effectiveness of these two points is especially important because it all has to happen quickly. With just-in-time production, runs are smaller, so generating 1,000 lbs of scrap for a 1,000 lb order is not an option. There is no time to dial in the line to achieve optimum results; it simply has to work right away.
Many film extruders are also looking to save some steps in the whole process. With 7- and 9-layer lines more prevalent and with advances in ink technologies, it’s very possible to build a film structure that won’t need to be laminated, saving costs in the long run.