Case packers are struck by lightening
As materials lighten up, things get heavy for case-packers.
The lightening of materials for both primary and secondary packaging is one of the biggest challenges for case-packing equipment. So is another sustainability-related issue: The increased use of recycled material in corrugated cases.
“The biggest inconsistency that we see is in the case materials themselves,” says Randy Spahr, executive vice president of Z Automation. “When you have inconsistency in corrugated material, it makes it difficult when you’re dealing with a high-speed application.” Spahr cited problems like inconsistent scoring of corrugated blanks and poor glue joints that make it hard to open the blanks or even make them stick together in the case-packer’s magazine.
Spahr readily concedes that the situation can be frustrating for an equipment supplier.
“It takes some time to get this identified sometimes, and at this point you and the customer both have put in money and time, and sometimes they’re not sure of what to look for,” he says. “They normally associate it with an equipment problem when it could be a material problem.”
Other case-packer suppliers echo this sentiment. “Any time you lighten anything it becomes harder to handle, usually less stable and less consistent,” says Mike Grinager, VP of technology for Brenton Engineering. To cope requires some adaptation, Grinager says: “Instead of maybe forming a case with just some generic plows, you may have to use a forming die to form the tray or case.”
CompensationFallas Automation has introduced enhancements in case erecting to compensate for weaker corrugated, says sales manager Chris Calabrese. A case-square feature allows adjustments to the side belts that move a case after the bottom has been folded. Photoeyes read the edges of the case and determine if they are exactly even; if not, one of the belts slows or speeds up slightly to compensate. This especially helps with cases that have a lot of “memory,” like those made with heavy corrugated or with die-cut windows.
As secondary packaging gets lightweighted, so does primary packaging, which presents its own set of challenges. The biggest one is in handling the lighter packages as they travel into and through the case packer. Beverage bottles have been especially lightweighted in the last few years, which means that they can no longer be counted on to push each other through the system and into the machine.
“If you can’t push the bottles with other bottles, now you have to have more sophisticated means of handling them to get them onto the tray,” Grinager says. These could include conveyor enhancements like variable-speed drives, separate tracks, or a conveyor braking system to make sure surge pressure doesn’t exceed what the thinner bottles can handle.
Flex timeAnother trend that case packers must deal with is flexibility. Trade customers in general want variety and customization, and that extends to case packing.
One of the most fundamental questions in changeovers is whether to rely on fixed, adjustable parts or change parts. “There are two schools of thought,” says Mark Jacobson, vice president of Econocorp. “One is, you can make the machine essentially completely adjustable, and the other is, you can make pre-engineered replacement parts that minimize judgment-go in one way, work one way, etc.”
Econocorp favors the latter approach. “I would pit my change parts against anyone that makes adjustments,” Jacobson says. “OK, maybe [it’s] a little more metal, but when I say go, who’s going to be running the next size faster? It’s going to be the person who simply takes the part out and quickly replaces it with another, rather than the person who has to move this a little bit and tweak that.”
Another issue that affects performance is integration. Should case erecting and case packing be done on separate machines, or should the two functions be integrated into one machine?
Calabrese says that about 15 years ago, integrated machinery was most in demand, largely because of its smaller footprint. But during the 1990s, customers started wanting separate machines.
“A lot of that came from the complexity of the changeovers for a machine that’s all-in-one,” Calabrese says. “Sure, it can be changed over to do a lot of different formats, but the changeover time was quite a lot.” Another factor is that integrated machines usually can’t run as fast as separated ones. Calabrese estimates that an integrated erector is good for about 15 cases per minute. But with increased demand for small case counts comes a corresponding need to run the case packer faster. “That kind of puts an integrated erector out of the picture,” he says.
Retail readyA retail trend that bears directly on case packing is the trend toward secondary packaging that’s ready to go on shelf with little or no modification. “As far as case/tray design is concerned, we see a significant shift toward retail-ready packaging,” says Bernhard Barta, vice president of sales and marketing for BluePrint Automation.
Calabrese says Fallas hopes to take that to the next step with a machine that’s now under development. It would be able to pack flexible bags so that they stand up, even if they’re not bottom-gusseted. The challenge is to develop a pick head that will pick up bags that have been indexed to a standing position by a lug chain and get them into the case without the contents settling unevenly to the bottom.
The end of a packaging line can be the beginning of its biggest challenges. The right case-packer can help meet those challenges, of lighter packaging, frequent changeovers and more. F&BP