Equipment in a starring role

Sticky developments in cartoning

In the mid-1970s, packagers saw cartoning line production rates reach 700 cartons/min, aided in part by dual-lane machines. Before that, carton production rates hovered around 80 to 150 cpm in the late 1960s, with straight-tuck and reverse-tuck closing styles available on single-lane machines. However, the development of hot-melt technology during the early 1970s spurred cartoning lines to reach higher efficiencies and line speeds, and reduced carton material. Hot-melt adhesives grew 20 percent annually, and packaging accounted for 54 percent of total hot-melt consumption from the 1960s to the early 1970s.

The biggest advantage of the hot-melt adhesive was the reduced compression time needed for adhering the carton's flaps to the structure. Cold gluing was also an option but didn't allow for quick adherence, and hot-melt cartoning machines required much less floor space than their counterparts. Hot-melt adhesives also offered various "open times," depending upon the desired length of time to set the glue. Besides the development of adhesives, the cartoning industry reaped the benefits of new adhesive-related equipment and microprocessor controls that contributed to an exciting and growing era for manufacturers.

Seal the deal
Some things don't change. High throughput and increased volume have always been the goals for packagers, and in the late 1960s form/fill/seal technology made a leap forward in this direction. New sealing techniques, along with gas-flush pouching offered the promise of higher volumes and more consistent machine reliability. The slow sealing process was cited in the October, 1969, issue of Modern Packaging as an economic obstacle for f/f/s. "Slow sealing techniques often put a restrictive floor under programs to lower per-pack production cost."

One of the first innovations regarding sealing was a rotary sealer for vertical f/f/s machines. This system used spring-loaded heat sealers/cutoff knives that rotated on the opposite side of the forming tube, mating in synchronization to effect top and bottom seals. The system was completely continuous-motion and could produce 600 pouches/min.

Another development in sealing during the late 1960s was a vf/f/s machine using a hot-melt applicator for lap seams. A major development for this system was the replacement of the fin-seal bars with rollers that ironed down the lap seams.

Instant gratification and zippered food pouches
During the late 1990s, high-speed Internet connections allowed for quick access to information and furthered the cultural mantra of instant gratification. This same cultural phenomena spread to food shopping aisles where zippered pouches for shredded cheeses and deli meats that allowed for quick and easy access to these products began to appear in the mid-1980s.

Packagers began moving away from premade pouches and toward bagging machines with in-line zipper applicators in 1990. The zipper applications consolidated the packaging process and in-line capabilities, and improved bonding of the zipper to the film. In September, 1999, PD reported that ITW Minigrip/Zip-Pak and DuPont Surlyn worked together to improve the sealing characteristics of the zipper systems to Surlyn® films, which were used for Thorn Apple Valley's reseable skinless smoked sausage package. Companies such as Robert's Packaging, Hayssen and Klöckner-Bartelt, to name just a few, began incorporating zipper applications into their f/f/s systems' designs.

Also, Dairy Foods magazine reported in 1999, "The growth of shredded cheese, packaged in convenient, reclosable packs, is driving overall cheese market growth. In response, packagers are tooling up to meet increasing customer demand for convenience options, such as premium easy-open and reclosable zipper lock features for nonshredded products such as sliced and chunked cheese."

Pressure-sensitive labeling
While pressure-sensitive labels were invented several decades before PD's debut issue, it wasn't until the 1960s that the impact of this form of labeling began to be felt on traditional wet-glue labeling solutions. It was in the midst of the Great Depression in 1935 that young entrepreneur R. Stanton Avery manufactured the first self-adhesive labels under the name Kum Kleen Products in a 100-sq-ft rented loft space in Los Angeles.

By the early 1960s, p-s label applicators had advanced from manual and semi-automatic equipment to fully automated machines capable of applying labels to even irregularly shaped packages. In its April/May, 1965, issue, PD reported on Avery's Model C and D self-adhesive labeling systems, the latter of which, it was reported, could "partially wrap labels around cylindrical objects." This opened the door for the use of p-s technology for primary packaging applications, rather than just for pricing and other informational labels on cartons and cases.

The automation of p-s labeling also played a key role in its ultimate domination over glue-applied labels. In 1964, machines labeling cartons with p-s roll labels were capable of reaching speeds of 60 to 80 packages/min; today, that number has increased to a top speed of roughly 1,000 ppm. Whereas, glue-applied labeling technology has maxed out at approximately 600 ppm.

Today's glue-applied labels are primarily printed on large-format sheetfed offset presses, with separate punching, varnishing and other finishing operations. Used for high-volume bottling and canning applications, wet-glue labels are applied using machinery integrated into the filling line. According to a presentation at Labelexpo Americas 2002, glue-applied labels control a 68-percent share of the food-package decorating market, 24 percent of the beverage market, and 5 percent of the household and personal care market.

In contrast, p-s labels, it was reported at the conference, have a 20-percent share of food, 59 percent of beverages, 89 percent of pharmaceutical labeling, and 51 percent of household and personal care applications. Many of today's p-s innovations are derived from clear or opaque film facestocks for the so-called "no-label look," which became popular in the 1980s and are still used today for premium beverage, cosmetic and pharmaceutical products.

Print-and-apply labelers
An offshoot of p-s labeling technology, print-and-apply found its calling with the growth in the use of Universal Product Code (UPC) symbology, which first came into practice in 1975. Reported an article in PD in December, 1979: "UPC had a flashy introduction that was followed by a long lull almost mistaken for death. That has changed. 'Today I can assure you that UPC is alive and growing like a bad weed,'" according to H.C. ('Skip') Heintzelman of Package Products Co. 'In 1978, the number of stores using UPC grew from 300 to 600. This year, the projection is that the number of stores will again double to 1,200.'" Print-and-apply technology allowed packagers to use preprinted or plain p-s labels and add bar-code symbology in-line.

The real advancements in print-and-apply have occurred within roughly the last decade, though. Developments include greater flexibility, enabling some models to handle numerous short runs and label a wide assortment of products; automatic adjustment for various shapes and sizes of packaging; and the ability to connect to enterprise-wide systems, operating from a database and able to provide real-time data.

Most recently, the trend toward mass customization of products and e-commerce, which has turned some markets into higher-mix, lower-volume environments, has opened another door for print-and-apply technology. The use of generic, preprinted cases coupled with customized print-and-apply labels in many cases is an ideal solution to manufacturers' inventory dilemmas.

Digital package printing
Making its debut in the commercial printing market in 1993, digital offset color printing penetrated package printing just two years later. In May, 1995, PD reported on "the first company in the world to install a direct-transfer, 'one-shot' digital offset press for flexible packaging." The company was Gellis & Sons, of Bnei-Brak, Israel, and the equipment a six-color Omnius™ digital color press from Indigo N.V.

Requiring no film separations, printing plates, proofing or press makeready, and printing directly from computerized data onto a web in industry-standard formats, digital color printing gave packaging converters a myriad of options not possible with offset printing because of the associated costs. Among them: the ability to create a variety of package designs for prototypes, test marketing, samples, promotional materials and more; make graphic or text corrections on-the-fly; use variable-printing technology for individualization; print short runs cost-effectively; and clearly reproduce small type.

Later in 1995, Engraph Label Group's Graphic Resources Div., Cold Spring, KY, began producing packaging labels with the Omnius, citing "reduced time to market" as the technology's greatest advantage.

By 2002, Packaging Strategies identified digital, "plateless" printing for label, folding carton and flexible packaging applications as "the leading projected growth category among all package printing and decorating technologies–expected to reach 20-percent annual growth through 2007." According to Packaging Strategies' 2002 figures, from 2002 to 2007, the digital printing market for labels is expected to grow from $70 million to $174 million; for folding cartons, from $17 million to $42 million; and for flexible packaging, from $4 million to $7 million.

Induction cap sealing
Induction cap sealing, a method by which a heat-sealable foil laminate inside of a closure is heated through a noncontact induction-heating process to produce a hermetic seal, was introduced more than 35 years ago, primarily to provide leak-resistance and barrier properties for bottled products. In the 1980s, pharmaceutical companies began to recognize the safety benefits of induction sealing for producing a tamper-evident seal. The technology didn't come into widespread use, however, until the Tylenol murders in 1982 prompted lawmakers to mandate that drug packaging be tamper-evident.

While the initial applications consisted of plastic containers with plastic caps, in 1980, Alcoa, Brockway Glass and McKenna Equipment pioneered the first successful commercial use in the U.S. of foil induction-sealed to glass. The product, Lipton's Instant Tea, was profiled in the September, 1980, issue of PD.

Over the last decade, many advancements in induction heat-sealing technology have been made by equipment manufacturers, including more efficient sealing heads that have reduced the power required to seal a container, and new designs that accommodate dispenser-style caps. Today, the list of materials used in induction-sealing includes most plastics–polyvinyl chloride, polyethylene, polypropylene and polyethylene terephthalate–and glass.

Specialized handling systems for lightweight, tipsy bottles
The advent of PET beverage bottles and other lightweight bottles in the 1970s required processors to incorporate packaging line components that could better handle these relatively unstable containers. Over subsequent years, to minimize possibilities of tipping, systems evolved with pressureless combining systems that use a series of conveyors of increasing speeds to merge bottles into a single file, rather than the flat transfer plates that have historically been problem areas even for heavier glass bottles. Rather than pressure, speed modulation keeps the bottles moving smoothly.

For long-distance transport, systems use air conveyors that support the bottles by rods beneath the neck finishes. Bottles discharge directly from conveyors into the starwheels or feedscrews of equipment, again without passing over transfer plates on which they could fall. Adjacent equipment is close-coupled, and monobloc filler/capper units minimize inter-machine transfers. A key development was systems to detect and eject fallen bottles before a jam.

Advanced controls added
The first programmable logic controller (PLC) was created in the U.S. in 1968, and PLCs began appearing in packaging equipment in the 1970s. Microprocessor controls began to replace solid-state electronic control systems in the 1980s, offering increased efficiency due to a capacity to handle more functions. The microprocessor made automatic feedback and correction possible on machines like netweighers.

The 1990s saw widespread adoption of PC control with touchscreen operator interfaces capable of displaying an array of information, including machine status, setup instructions, fault-clearing advice and maintenance manuals. Some machines even have self-diagnostics and modems so they can initiate calls for service. In many cases today, the PC control on one machine–typically the filler–oversees the entire line.

The 1990s also saw a move into the implementation of servo drives on packaging equipment. This was characterized by three segments:
Generation 1, Circa 1990–One or two servo drives were added to existing mechanical machines to improve controllability. Result: Added cost and complexity.

Generation 2, Circa 1995–Multiaxis servo systems are implemented, but machines still utilize belts, chains, pulleys, etc., and servos typically do not provide absolute feedback. Result: Increased flexibility, but no parts reduction.

Generation 3, Circa 2000–Multiaxis machines designed from the ground-up, to exploit servo technology. Result: Parts reductions by as much as 50 percent, modular, configurable, improved sanitation, higher throughput, easier to operate and maintain, and up to 30-percent reductions in price.