To simplify changeover of its case packer, the Welch Foods Inc. (www.welchs.com) plant in Kennewick, Wash., modified the packer so the working area could be expanded to let workers remove change parts more easily, either manually or using an overhead crane. As a result of the modification, changeover is "more convenient. It's not too complicated or too congested to pull the parts out," says Marty Gardner, Welch Foods' director of plant operations-West Coast.
The role of automation
Recognizing the need for fast changeover, and the role of simplicity in achieving it, packaging equipment makers are engineering automated changeover features into their products to reduce the number of time-consuming manual adjustments.
As an example, the Rovema VVI-200 vertical form/fill/seal machine, from Rovema Packaging USA (www.rovema.com), Lawrenceville, Ga., provides automatic size changeover with the push of a button. The machine's forming collar adjusts automatically, so a forming-set change is not needed when changing between package sizes.
For labeling applications, the KHS Innoket RFL roll-fed labeler, from KHS AG (www.khs-ag.com), Dortmund, Germany, is designed as a linear system with few change parts. Thanks to the linear design, the labeler does not incorporate infeed stars, discharge stars, guide curves and turntables. The result is uncomplicated handling and quick changeover.
|Servo drives, which automatically adjust items such as the carton magazine and side rails, can save an enormous amount of time during changeovers.
The CH7.5-250C horizontal cartoner from Z Automation Co. (www.zautomation.com) (ZAC), Arlington Heights, Ill., incorporates seven synchronized servo drives. The cartoner's servos automatically adjust items such as guide rail and magazine positioning when it's time to change carton sizes. Further, the cartoner can be fine-tuned at full speed, which helps minimize the start-up period.
According to Zoran Momich, ZAC's president, changing over this horizontal cartoner takes five to 15 minutes, vs. 1.5 to 2.5 hours for a traditional changeover of this magnitude.
Automatic adjustments offer valuable time savings during changeover. On one of ZAC's vertical cartoners, the model CV15-100C, items such as the carton magazine, rotary feeder, side rails, carton track and carton closing height are all automatically adjusted. The benefits of automatic adjustments "include the flexibility to run multiple products and a large range of carton sizes on a single machine with minimal downtime because of tool-less, fast, repeatable changeovers," Momich says.
Programmable controls also play a key role in speeding up changeover. For example, programmable controls built into vacuum/shrink packaging equipment from Reiser (www.reiser.com), Canton, Mass., make it possible to switch between shrink and laminate bags with no set-up changes.
The Reiser Supervac Vacuum Chamber Belt-fed machine is configured inline with the company's Supervac AT10 automatic shrink tank. To switch over from shrink bags to laminate bags, the operator pushes one button on the belt machine to select the stored program for laminate bags and switch off the dipping mechanism at the shrink tank.
The pit crew
In the real world, automation is just one part of the changeover picture. Personnel also are enormously important. At Welch Foods' Kennewick operation, training for operators, mechanics and maintenance specialists includes sessions with equipment suppliers as well as in-house experts.
The Kennewick plant packages a variety of juices, concentrates and spreads in glass, steel, aluminum, spiral-wound composite, PET and polypropylene containers ranging in size from 10 to 64 oz. To keep up with demand for the many variations in package type/size and product type/flavor, the plant's personnel have become changeover experts. "It's typical for us to go through multiple flavor changeovers per day, and often multiple changeovers per shift," says Gardner. "That's true across most of our lines."
Automated adjustments to items like guide rails help equipment operators minimize changeover time. Rail adjustments for the various package sizes are all electronically pre-set; the operator simply dials in the new package size, and the rails automatically adjust. "We no longer have to start each new package size with trial and error," Gardner says.
This example illustrates Welch Foods' growing emphasis on bottle handling equipment, which is linked to the company's increased use of lightweight plastic containers. The goal is to avoid excessive back pressure on plastic bottles during conveyance and accumulation, because the pressure can damage the bottles.
"Historically, what has dominated the changeover discussion has been unit operations, where you fill, cap, label, package and palletize," Gardner says. "But as the package itself becomes lighter, it puts a lot more emphasis on the bottle handling and conveyance that transfers the container from unit operation to unit operation. Changeover has evolved in the industry, and here as well, to be just as critical for conveyance as for unit operations."
With the development of lighter-weight containers, each of Welch's lines has evolved into an integrated system. Unit operations no longer work independently. Changing over the synchronized lines requires adjustments at many points within unit operations and conveyance/accumulation, and it demands tremendous coordination of personnel. In fact, the changeover tableau is not unlike an Indy 500 pit stop.
Some in the beverage industry have actually taken their mechanics and operators to race-team pit crews to evaluate and improve changeover techniques. Gardner reflects, "It's a great idea. If we had a race track nearby, I would have done it already."
NOTE TO MARKETING
Consumer demand for new package sizes and structures can easily lead to a proliferation of SKUs. Athough the availability of 20 different sizes and multipack configurations of a product may delight consumers, plant operations is typically less than enthusiastic about the frequency and complexity of changeovers required to produce so many variations.
The changeover downtime generated by the more-SKUs marketing strategy can cut, sometimes severely, into production efficiency. When that happens, the overall profitability of the company suffers.
John Henry of Changeover.com advises marketers: "When you first come up with an idea for a new product, talk to the people on the floor in operations who know the machinery and its capabilities. See what the implications of that new product will be."
Failing to do so can lead not only to lengthy changeovers but also to packaging-supplies waste. Henry recalls a rum distiller whose marketing department designed an elegant new package, an inverse-taper bottle, with the intention of running the package on existing filling lines.
The marketing department didn't discuss the new package with operations before creating molds and authorizing bottle production. The first shipment of bottles arrived in the filling plant, but when operators tried to run them, the top-heavy bottles toppled over on the conveyor.
The bottles were incompatible with the filling line, and the distiller had to trash all the inverse-taper bottles. Ultimately, the company redesigned the new bottle to include a ring around the base so it could run without modifying the filling line.