In the food and beverage industry, shelf appeal can make or break a product launch. And in a marketplace where choices are seemingly endless, attracting consumer attention is an uphill battle.
For beverages, unique bottle silhouettes and compelling label designs often play equal parts in establishing market presence. At the same time, minimizing packaging materials – and optimizing manufacturing efficiency – are always important considerations.
“Unlike glue-applied labels, full-sleeve shrink labels allow manufacturers to take advantage of the entire landscape of the bottle for marketing purposes,” said Chris Thomas, director of controls technology, Axon. “Shrink sleeves enable optimal product representation – and can be adapted to virtually any bottle shape.”
Based in Raleigh, North Carolina, Axon manufactures applicators for heat-shrink sleeves, tamper evident bands and stretch sleeves, as well as a full line of heat-shrink tunnels. The company is a division of Pro Mach, a leading provider of integrated packaging products and solutions.
Ultra-Thin Film Application Challenges
With the advent of ultra-thin films, shrink labels can now be made with about half the amount of plastic as conventional options. Not only do lighter films reduce packaging material, but they are also becoming increasingly available in eco-friendly biodegradable options.
Ultra-thin films also can shrink faster in the heat-intensive shrink tunnels – and can thereby help reduce energy usage.
“No doubt, there are many advantages,” said Thomas. “But applying film as light as 25 microns poses significant challenges.”
With handling characteristics that mimic that of facial tissue, ultra-thin films are difficult to control. Especially in high-speed applications, achieving consistent label placement requires extraordinary accuracy.
“Thicker film tends to work its way around the bottle if it catches the product slightly off-edge during application,” Thomas said. “Ultra-thin film is unforgiving – and when things go wrong, they go wrong very quickly at high speeds.”
Maintaining Accuracy, Optimizing Speed
To address the challenges of ultra-thin film, Axon recently introduced the SLX high-speed shrink sleeve applicator, designed for films from 75 to 25 microns. Featuring a compact footprint, the SLX is one of the most advanced single-head inline systems available today.
“Our initial goal was to maintain accuracy and set speed records with this machine,” Thomas said. “Depending on model, the SLX is rated at 600 to 800 products per minute (ppm) – and can surge to 1000 ppm in certain conditions.”
The key to this extraordinary performance is three-fold. First, the machine maintains precise product positioning, thanks to a dual timing screw on the infeed. Second, the mandrel-style applicator features patent-pending film delivery technology. And finally, the equipment runs on the latest control platform from Rockwell Automation, including the Allen-Bradley® CompactLogix™ 5380 controller and Allen-Bradley Kinetix® 5500 servo drive.
Control System Meets Demands
To achieve optimal speed on the continuous motion machine, Axon required a controller with processor capacity that could maintain accuracy in a high production environment. When a machine of this type runs at high speed, a one millisecond delay in response time translates into a few millimeters of distance.
“When we started product development, the CompactLogix 5380 didn’t exist and – I wasn’t sure we would be able to achieve our goals,” Thomas explained. “But I was pleasantly surprised by the processor performance.”
“And the Kinetix 5500 servos hold their position really well,” Thomas added. “Plus, they have adaptive tuning and load observer functionality. It all just worked – immediately.”
The load observer and adaptive tuning features enable smart machine functionality by automatically tuning the drive to electrically compensate for unknown mechanics that can change over time.
The SLX is also built to enable seamless film roll changes, thanks to an auto-splice unit. And the equipment eases product changeover with an electronic format monitoring system that guides mechanical tooling adjustments. The machine can be readied to run a new product within 10-15 minutes.
Looking toward the future, Axon hopes to develop ways to improve the overall energy efficiency of shrink sleeve technology.
“Ultra-thin films help conserve energy, but one of my goals is to design shrink systems that consume less energy overall,” Thomas said. “That’s the next hurdle for the industry.”
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