Transport Packaging: Wrap Up

Transport Packaging: Wrap Up

Sheetz applies drive-through efficiencies to the stretch-wrapping process in its DC.

Sheetz Convenience Stores (Altoona, Pa.), is recognized within its industry as a benchmark for convenience store innovation. It created the "convenience restaurant"—a modern, quick-casual restaurant powered by touchscreen terminals—at the drive-through and inside. Realizing that what works outside can work inside, managers applied similar drive-through efficiencies to stretch-wrapping operations at its distribution center in Claysburg, Pa.

A fast-growing company, at the time of this writing, Sheetz has 310 locations, 10,000 employees and $2.8 billion in annual revenue. To capitalize on the efficiencies from using double-pallet jacks for moving mixed loads, the company set up several pairs of freestanding overhead stretch wrap-pers from Lantech (Louisville, Ky.).

"The arrangement creates a wrapping lane for the pallet jack operator to pull in parallel with the stretch wrappers," says John Barger, shipping supervisor.

Combined with other technology efficiencies, such as wearable RF terminals for order picking, the stretch-wrapping operation has helped the distribution center respond to a 13% annual increase in volume in the last two years without an increase in worker hours or equipment, says Bargar.

Convenient unitizing
The Claysburg DC spans 360,000 sq. ft. It employs 150 and operates 12 hours a day, six days a week to support all of company's the retail outlets. Pallets are staged for full-case picking with totes containing cigarettes and each-pick items for a given store, along with a packet of preprinted shipping labels for cases.

Using wrist-mounted RF display terminals from Symbol Technologies (Holtsville, N.Y.), case pickers equipped with double-pallet jacks are provided directions to one of 4,000 SKUs. The RF terminals receive data from the warehouse management system. Pickers apply preprinted labels to cased goods as they're selected, then move the loaded pallets to the stretch wrapping station.

On the advice of Lantech and a design consultant, Sheetz arranged its stretch wrappers to work as pairs. Two pairs were arranged back to back in the material transfer zone between the ends of the racks and the dock area. Another pair was arranged side-by-side on the cold food dock. This configuration allows a double-pallet jack to be driven into a wrapping lane, parallel to a set of wrappers. The operator drops one pallet, then pulls forward and drops the second. He's then free to begin picking again.

A checker at the wrapping station makes a final inspection of each load, then pulls a lanyard to initiate the wrap cycle. When the random-size loads are finished, the operator takes the wrapped pallets to a staging area for the truck loaders.

Barger says the stretch-wrapping machine is "almost" automatic. It requires nothing more from the operator than a pull on the lanyard. The machine automatically attaches the film to the pallet then cuts it at the end of the cycle. Each machine produces 30-40 loads per hour, wrapped with two layers of film, prestretched 200% with a power roller stretcher. The distribution center currently prepares 600 pallet loads—26 tractor-trailer loads—per day.

Automatic load-height detection adjusts film overlap to meet the requirements for Sheetz's variable-size loads. These loads can range from knee-height to 80 inches high. Sheetz uses a 70-ga. film. Being able to vary the wrap force on the machines allows the operator to adjust for unstable loads or soft products.

"When we opened [the distribution center], we did a lot of hand wrapping before we got these machines on line," says Barger. "Consequently we had some issues with loads shifting in the trailer."

That problem ceased when it went to machine wrapping. Barger says that the pairing of the wrappers is an exceptionally efficient layout for the double-pallet jacks.

"We initially had the wrappers separated, but paired them up and added more machines," he says. "This improved our productivity to meet growing volume requirements during the next few years."

After mixed loads are dropped off and during the final check, wrap force can be adjusted for unstable loads.

Sheetz uses four Lantech overhead stretch wrappers arranged back-to-back that create two drive-through wrapping lanes.

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