Stretch wrappers 'feed' on dependability

Grant Gerke

January 29, 2014

6 Min Read
Stretch wrappers 'feed' on dependability


Uninterrupted unitizing of pallets can be music to a plant manager's ears. In the music city of Nashville, a Purina Mills, LLC, processing and packaging plant relies on two stretch wrappers to distribute packaged animal feed.

Orion Packaging System's HPA-66 model and soon-to-be installed MA-55 (see sidebar) unitize 20-, 25-, 40- and 50-lb bags of animal feed for horses, chickens, cattle and cows. The Purina plant needed a stretch-wrapping system, and Marc Lewis, plant manager, went with the model after attending PACK EXPO 2000. "I pushed hard to buy Orion because of its design and its straightforward operation. The machine has minimal moving parts and can be easily fixed on-site by our maintenance staff. However, I've had minimal problems with the machine," says Lewis. The stretch wrapping system has been operating since March '01.

The plant's business model is fill-to-order fulfillment. A customer calls in an order and the plant will fulfill it within 48 to 72 hours. The 60,000-sq-ft plant packs and distributes animal feed to southern and midwestern states.

One of the two stretch wrappers, above, unitizes a pallet of uniform, animal-feed bags. The machine averages 16 to 20 revolutions to wrap a load.

The plant consists of processing and packaging areas. The animal feed is processed and delivered by a conveyor to a vertical bag-filling machine. Once the animal feed enters the bags, they are manually placed on a conveyor and moved to a Lambert Material Handling palletizer, Model 1200 that can palletize 25 pallets/hr.

Then, forklift operators pick the 40 x 48-in. wooden pallets from the conveyors and prepare them for stretch wrapping. Pallet Recyclers provides the wooden pallets, and Purina uses 660 pallets/day for its operation.

Orion customized the two, semi-automatic stretch wrappers with concrete guides and lanyard switches. The concrete guide is fixed on both sides of the machine's turntable, and enable the forklift operator to "feel" for proper alignment in loading the pallet.

The second customization–lanyard switches–allows the operator to start the stretch-wrapping machine from the forklift. The switches hang from the ceiling and are activated once the pallet is in position. Both of the customizations allow the forklift operator more operation time transferring pallets to their destinations. Although the HPA-66 is capable of wrapping up to 35 loads/hr, Purina averages 20 to 25 pallets/hr, PD is told.

Keep it clean
Lewis says the objective of the stretch-wrapping system is twofold: product protection; and a organized and clean warehouse. However, the HPAs' provide another vital role–stretch wrapping hand-picked pallets.

The Purina plant handpicks 45 percent of the products that it ships out. Due to the nature of the fill-to-order business, a pallet may be filled with many different sized and weighted bags. A pallet can hold anywhere from 20 to 40 bags. Lewis adds, "We may have three different sized products on the pallets at the same time."

The film that holds these bags together is made up of 90-ga polyethylene, supplied by Paragon Films. The 5,000-ft roll of film is pre-stretched to 245 percent by the HPA's Insta-Thread delivery system. Two textured rollers inside the delivery system stretch the film, with one roller turning faster, allowing for the stretching action upon the film. This pre-stretching cuts film usage costs.

After picking these 1,000- to 2,000-lb pallets of animal feed, forklift operators deliver to two different stretch-wrapping machines. The machines are located at different locations in the packaging and distribution area. With space at a premium, the HPA-66s are located in separate areas, to ease traffic congestion. The structural-steel stretch wrapper is capable of pallet loads up to 4,000 lb.

After the film is pre-stretched, the film winds to a clamp/cut/wipedown station in front of the pallet load. From there, the HPA-66 turntable rotates, on average, 16 to 20 times per load.

Top, the machine wipes down the film tail after wrapping a load. An impulse hot wire cuts the film, and the pneumatically operated wipedown device (black roll) tamps the film to the load, leaving no loose ends. Above, yellow, concrete guides on the turntable give forklift operators a sight and feel cue for correctly loading pallets.

An impulse hot wire cuts the film. The hot wire moves toward the pallet, and the machine secures the film tail to the load with a pneumatically operated wipedown device. The wipedown mechanism is adjustable.

The HPA-66 comes with the Revo-Logic™ Exact Wrap counting feature that counts the number of top and bottom wraps set at the control panel. With Revo-Logic, the top or bottom wrap is counted precisely from where it started. The system measures from different points around the pallet load, providing a more precise measurement of revolutions, PD is told.

Cost containment
The bottom line appears everywhere in the fill-to-order business model, and in this example, it is characterized by small margins. "With all agricultural type products, our business is extremely cost-sensitive. Everything we save goes to the bottom line," Lewis informs PD. "The Orion MA-55 installation [see sidebar] should increase distribution volume by a considerable amount compared to last year." Hearing those numbers is music to any manager's ears.

More information is available:

Pallet stretch wrapper: Orion Packaging Systems, Inc., 800/333-6556. Circle No. 243.

Palletizer: Lambert Material Handling, 800/253-5103. Circle No. 244.

Pallets: Pallet Recyclers, 615/252-6080. Circle No. 245.

Stretch film: Paragon Films 800/274-9727. Circle No. 246.

Pack EXPO show: Packaging Machinery Mfrs. Institute, 703/205-0923. Circle No. 247.


Increased efficiency

At presstime, the Purina plant will have added an Orion Packaging System's MA-55 automatic stretch wrapper to its packaging and distribution arsenal. The new machine should allow Purina to increase its '01 distribution volume by a considerable amount. The rotary-tower stretch wrapper will be part of the animal feed packaging line. The in-line stretch wrapping will remove a step in the present stretch-wrapping procedure at Purina. Forklift operators will not have to place individual pallets onto the standalone HPA-66s. Instead, the stretch-wrapped pallet will be picked from the packaging line, ready for distribution. Marc Lewis, plant manager at Purina, says, "The forklift operators will take the stretch-wrapped pallets directly to the trucks for distribution. From a time-saving standpoint, the investment [MA-55 purchase] will pay for itself by cutting down on the 'extra-step' of stretch wrapping. The MA-55 will definitely increase efficiency."The MA-55 can wrap loads at 70 loads/hr and has a weight capacity of 4,000 lb. The machine comes with the Insta-Thread film delivery system, PLC controls, a film-tail cut-and-wipe component, and a 0- to 16-rpm tower drive.

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