GNC Thrives With Thermal-Transfer Coding

Master-slave configuration reduces downtime and printing costs on VitaPak lines.

Nutra Manufacturing is the manufacturing arm of General Nutrition Centers Inc., better known as GNC, the nation’s largest retailer of vitamin, mineral, sports nutrition, and herbal supplements. Nutra Manufacturing is based in Greenville, SC, but has a warehouse, distribution, and packaging facility in nearby Anderson, SC. There, two dedicated vertical form-fill-seal lines for VitaPak daily or twice-daily supplement pouches, manufactured for both GNC and third-party customers, hum to the tune of 65 million packages per year, all of which need to be properly coded before entering the supply chain.

In late 2004, Nutra Manufacturing began using multiple Videojet DataFlex thermal transfer overprinters (TTO) to print data, lot numbers, and expiration dates on the two VitaPak lines. The company worked with Videojet to configure the three DataFlex printers so all code changes could be made from a centralized control module on the line. This new master-slave format was so successful that the same configuration was developed for the other VitaPak line a year later.

“When I arrive in the morning, it takes about a minute at most to change the code on the DataFlex printers,” says line lead machine operator Damell Parker. Parker has worked for Nutra for six years. “I can make the changes when the line is running, so there is no delay in productivity.”

Nutra Manufacturing codes 65 million VitaPak supplement pouches per year.

Nutra Manufacturing’s Greenville facility manufactures up to 13 billion tablets, hard-shell and soft-gel capsules annually. All of that product is transported to Anderson for packaging, on the high-speed bottle packaging lines, thermoformer blister machines, or the high-speed continuous-motion VitaPak lines.

John Theofanous, Nutra’s packaging operations manager, says that marking 65 million VitaPak packages annually translates to roughly 357,000 packs in a 24-hour period. Thus, the company’s coding solution has to be robust for a variety of reasons, including the need for regulatory compliance and audits, which are industry necessities.

He says the Anderson facility is regularly audited by FDA and its counterparts from 48 countries around the globe, along with the National Sanitary Foundation and private-label customers. With the addition of various internal audits, Theofanous estimates that the Anderson facility is audited roughly every other week in some form. One of the big components of the auditing process is verifying the readability of codes placed on packaging.

But regulatory compliance is only part of Theofanous’s concern. “We hold ourselves to a slightly higher measure when it comes to marking and coding,” he says. “There are typically 30 VitaPaks in one carton, and if one VitaPak in a carton has a code that is illegible, that carton fails our internal quality process. This is not an external regulation—that is our level of acceptance. It’s also a challenge considering we’re marking up to three lines of print.”

That means crisp, clear codes are vitally important in order to minimize the cost of tearing open packages and removing the product when a carton doesn’t pass inspection.

Theofanous says the VitaPak lines previously ran three dual-head continuous ink-jet printers for several years. But the only way to effectively mark the packages was random scrolling print, meaning the printers constantly printed along the backs of the packages, resulting in codes that were cut off when the packages were separated. While not as optimal as printing a dedicated per-package code, it was a workable solution. But there were other issues with which Theofanous had to contend when it came to the ink-jet printers.

“At times, we would have downtime for maintenance—the heads needed to be cleaned, or a tune-up was necessary,” he says. “Many times, once that issue was addressed, the process to refresh the fluids would take from 30 to 45 minutes. That’s costly downtime.”

In 2004, several private-label customers began requesting more lines of print on their packages, which created a new challenge for Nutra. Customers wanted the capability to add kosher symbols or use a particular font size in the future, which wasn’t easily achievable with Nutra’s existing ink-jet printers.

All those new requirements, along with the rising cost of consumables like ink and makeup fluid, were the impetus for Theofanous to look into a new coding method and the one that intrigued him the most was Videojet’s TTO solution.

DataFlex printers are configured so all code changes can be made from a centralized control module.

TTO systems feature a thermal transfer printhead and ribbon that make contact with a flexible substrate, like the synthetic films and labels that comprise VitaPak packaging. Miniature print elements under a glass coating heat small areas of the ribbon and transfer ink to the target substrate. Print elements are program-controlled to create real-time images, including clean, high-resolution bar codes, text, and graphics.

The latter feature was especially intriguing to Theofanous given customer requests for more lines of print and the ability to add graphics.

“We came up with the concept of using a larger, wider printhead on three machines, meaning each printer would be able to mark two packages at a time,” Theofanous says. “But having three control units on the three printers wasn’t ideal from a cost and efficiency perspective.”

“Videojet suggested a master-slave configuration,” he says. “In order to create a good VitaPak, we can’t affect the tension on the film, so we worked with Videojet’s engineers to create a new assembly, that not only included mounting hardware for the printers, but reconfigured our drive rollers to prevent drag in the system.”

It took some coordination to make the new configuration work in concert with the DataFlex printers, but it paid off for machine operators like Parker. The control module on his line has three screens, representing the printheads on the three DataFlex printers. Moving from screen to screen is done with the keypad’s tab function. Within each screen is the ability to choose the left or right print side. Changing the code itself requires a few simple taps of the DataFlex’s touch screen.

Thus, at any given time, the three printheads could be printing six different types of variable data. But what impresses Parker even more is the consistent crispness of the codes, especially considering how many VitaPak packages he runs during his 10-hour shifts.

“I’ve been working with the DataFlex printers on my line since we got them,” Parker says. “I run roughly 130,000 or more packages during my shift. Top speed is 155,000 to 165,000 packages. Code consistency over that time has been great.”

Operations specialist Mike Kelly handles the maintenance on the DataFlex printers, which he says is an easy job because there is so little maintenance compared with when Nutra used the ink-jet printers. Therefore, he’s able to devote his time to more pressing projects.

“I used to spend a lot of time calibrating the ink-jet printers, but with the DataFlex printers, I just change the ribbon and use a cotton swab to wipe the printhead, and that’s pretty much it,” he says.

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Theofanous says that originally the DataFlex printers were used to code exclusively VitaPak packages for private-label customers, but after seeing the improved print clarity, corporate requested usage of the DataFlex printers on all GNC VitaPak products as well.

But perhaps the biggest benefit, Theofanous says, is “our operators are less conscious of print errors and more focused on making sure we produce good-quality packs.”

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