Generally bags of soil mixtures sold at lawn and garden centers don't need to be in pristine condition when they arrive at the retailer. Because of the atmosphere in the plant where they're packaged it's almost impossible to avoid some dust and dirt. What isn't acceptable today is a heavy layer of dirt that makes it hard to read the product identification and the brand name.
Since pallet loads of bagged soils are usually stored outside especially on the West Coast the only way to keep these bags clean is to wrap the loads in protective film. Not just a spiral wrap around the sides of the load but also a top cap that protects the top layer of bags from the elements.
It was just this situation that led Bandini Fertilizer Vernon CA to find a load wrapping system that would protect its loads from the weather and the contamination that could accumulate on them in the plant's own outside storage.
Bandini's answer was an automatic stretch wrapping system from Orion Packaging (Memphis TN) that included the addition of a top sheet to protect all sides of the pallet load from the elements. Because of the plant's space restrictions and the requirements of the company's loads it was far from an "off the shelf" installation. Here's why:
* The production line at Bandini left little room to add an automatic stretch wrapper at the end of the automatic palletizer. Eventually the plant had to open up a plant wall and add a roller conveyor to carry finished loads out to the storage yard.
* Because of Bandini's oversize pallet wrapping systems designed to handle the 48 x 40" grocery pallet wouldn't work. Thus Orion had to enlarge its wrapper conveyors the turntable and the top sheet system to accommodate the larger load size.
* Thanks to the company's 56" long pallet size the film roll for the top sheet system had to be mounted across the conveyor. That way the film rolls wouldn't be so wide they couldn't be easily handled.
* Since the wrapper was to be mounted adjacent to not one but two open doorways the top sheet system had to control the sheet even when breezes were blowing into the plant.
* To work within Bandini's capital expenditure plan Orion had to design the oversize stretch wrapper to accept a top sheet system that wasn't going to be installed until almost a year later.
The key to the success of this project was the determination of Orion's Western sales agent Bob Zwick. "When I first talked with the Bandini engineers they said: 'This is what we'd like to do but we can't fit it in.' When someone says 'can't' I really perk up" he says. That challenge put Zwick to work on his own computer-aided design system long before he asked the Orion engineers to work on the installation. Along with Zwick the sale was made through Orion distributor Gulf-Pacific Packaging (Vernon CA).
Before the new installation was completed in late spring Bandini sent out most loads without stretch wrap. Packaging World asked Bandini plant superintendent Art Pellegrini what the plant used before. "Nothing" was his reply and a slight overstatement.
"If a load needed to be stretch wrapped our people would do it by hand" he reports. "We had portable units that required a forklift driver to remove the load from our line wrap it in film and then place it back on line or onto a truck for delivery. This process required at least one and sometimes two workers to accomplish. So it was time-consuming and inefficient and we still didn't have a top cover on the load."
Increasingly more of Bandini customers were asking for fully-wrapped loads says Don Knipp marketing manager as a way to keep them clean. Bandini customers wanted the assurance that when wrapped loads were unwrapped the top tiers of bags would not be so soiled that the customer or the consumer couldn't even read the name of the product.
To avoid this problem and to provide load integrity the company looked at pallet wrapping with a top cover.
Tough on equipment
The soil and fertilizer business has a reputation for being very tough on machinery because the plant environment is dirty dusty and acidic Zwick says. Fortunately Orion's NEMA 12 gasketed electrical cabinets keep the sensitive electric and electronic components away from contamination. In addition Bandini had already some experience with smaller Orion wrappers; it has operated two small portable stretch wrappers.
"We wanted a system that would be fully automatic just like our palletizer. We wanted a high-quality system that would be easy to maintain" notes Pellegrini. "We decided to go with Orion because of their track record for building tough equipment. Plus it was compatible with the rest of our equipment and our maintenance people preferred it."
When it came time to install the top sheeter this spring Orion was concerned about the wind factor. Immediately after the stretch wrapper loads move through an open doorway leading to a roller conveyor that carries them out to the yard. Another large overhead doorway often open is also adjacent to the side of the machine. So Zwick worried about how to control the top sheet when breezes blew in through the doors.
"Just a good puff of wind could blow it out of position so that it wouldn't be secured to the load" Zwick says. "We added a top platen to kind of hold the piece of film in place."
However the most difficult aspect of the installation was the limited space in the Bandini plant.
"The new wrapper fit in-line with our current bagging system" Pellegrini says. "To get it to fit with our automatic palletizer we did make a few changes to the side of our plant but nothing major." That's a bit of an understatement.
"When we designed in all the changes our system actually ended up being about eight inches longer than the room" Zwick recalls. "So they had to cut out part of the plant wall." Later when the top sheeter was added the plant had to remove and relocate a catwalk that would have interfered with the sheeter.
Bit at a time
"We couldn't install the complete system at one time because of budget constraints" says Pellegrini. "We had appropriated so much for capital expenses and that took care of the wrapper. The top sheeter was a great feature but we decided to wait until this year."
That's easy to say if all the equipment is "off the shelf." Since it's not the extended wrapper system had to be built with the top sheeter in mind. This project depicts the company's ability to customize equipment for a user's needs Zwick points out. "We started with a standard machine the FA55 but then we enlarged the machine the turntable the conveyors and the top sheeter too. Virtually everything had to be changed because of their large loads."
Bandini uses different pallet sizes but the largest measures 48 x 56" well beyond what a regular machine can easily accommodate. Combine that with tight quarters Zwick says and Orion had to plan the location for the top sheeter console and even the positions for the sheeter legs. And all before the stretch wrapper went in.
Because of the tight quarters Orion engineered the top sheet system to dispense and cut the sheet in the flow direction over the turntable. Normally top sheets are dispensed from the side of the conveyor. To cover a load with a footprint of 56" long the film roll would have been too long to be easy to handle. Even dispensing top sheets this way the system uses a 72"-wide roll of low-density polyethylene film that's supplied by Gulf-Pacific.
Still roll replenishment had to be considered. So Orion engineered a film carriage system that lowers with motors and counterweights down to the conveyor level for easy loading of the large film rolls. The carriage also has a second mandrel for a spare roll of film to cut in half the amount of time needed to switch from one film roll to another.
Normally top sheets are applied to loads at the infeed of the wrapper not above the turntable. In Bandini's arrangement there is no room for an infeed that would permit the application of the top sheet. So this installation is just about as customized as the equipment itself.
Building custom equipment didn't extend the delivery schedule Zwick says. Cooperation was very good between the two companies especially the maintenance staff that assisted Orion in helping to change the programming from the palletizer on back.
For the most part says Pellegrini the company fills plastic bags with 1.5 and 2 cu ft of a variety of soil products. These include top soil potting soil planting mix vegetable mixes and special mulch mixes. About 90% of the volume is packaged under the Bandini name.
"On an average day we run between 3 and 5 bags per shift" he says. "The line can easily handle up to about 7 bags if we need it. So we're regularly doing about 95 pallet loads each shift.
"We may be adding production of either one- or one-and-a-quarter-cubic-foot bags on this line in the future since we have some extra capacity." The palletizer is the limiting factor on the line now; the stretch wrapper runs well under its top output.
As a pallet load (usually 48 bags) is ejected from the palletizer it travels a few feet and directly onto the enlarged turntable of the stretch wrapper. Overhead the LDPE film has been unwound in a frame several feet above the load. A pneumatic platen and the film frame both descend to the top of the load. When the platen secures the film to the top of the load a cutter cuts the film from the web and the frame releases the film.
After the edges of film settle around the sides of the load the platen and film frame return to their original position. At this point the automatic stretch wrapper tucks the spiral wrapping film in the load and begins its wrap cycle to completely cover the load sides and to secure the top cap to the load.
Once the spiral wrapping is completed the load is ejected from the turntable and moves out of the plant on a powered roller conveyor. In the yard a forklift transfers the load to a position for storage or directly onto a flatbed truck trailer.
Bandini currently uses an 80-ga PowerGard® a coextruded linear low-density polyethylene film made by Presto Products (Appleton WI) in a 20"-wide roll. The film carriage on the spiral wrapper is set for a prestretch of 230% to help cut down film usage. Like the 1-mil thick top sheet the film is purchased through Gulf-Pacific.
Not only does this process make Bandini's customers happy it gives the plant an unexpected production edge. "A major benefit is that we can now build an inventory of our products without having to worry about the bags becoming a problem in our yard" says Pellegrini.
"So this keeps our inventory looking good and it makes a better looking package for the customer. We've also found the truck drivers like it too. It offers more load security plus the bags don't pick up any dirt or contamination on the highway. It's been a good change for just about everyone."