A stretch wrapper applies a second layer of film, trapping all four edges of the top sheet.
A load from Basalite leaves the plant and is off to a customer. Forklifts do not damage the film cable.
In today's fast-paced bagging and palletizing operations, producers can't afford to have a misaligned stack or broken bag slow things down. And because more and more of a producer's product is now shipped further, load stability is an increasing requirement.
Managers at Basalite Concrete Products, one of the largest producers of concrete products on the West Coast, faced this challenge when they recently opted to upgrade one of the bagging facilities. With 11 facilities, including some retail yards and mining operations, located from Denver to the west, and north to British Columbia, they wanted to find a wrapping system that would be safe for both employees and customers, yet it had to be cost-effective.
Employing about 700 people, Tracy, Calif.-based Basalite produces bagged dry concrete and many types of block, retaining wall stone, and pavers. It sells these products to major home centers and independent dealers.
Basalite's new facility in Dixon, Calif., has two production lines for bagged product. One is among the first in the country to use form/fill/seal packaging for concrete. Made by Premier Tech of Quebec, the form/fill/seal line churns out 1000 to 1300 bags per hour, using a 5.5-mil plastic material.
“This package improves housekeeping for our customers and protects the product from moisture absorption better than paper bags,” says Fritz Anthes, Basalite's special projects manager. The other line uses conventional self-sealing paper packaging. This line runs at similar speed. Products range from 50-pound bags of fencepost mix to 94-pound bags of type S mortar.
The bags are robotically palletized, then roller-conveyed to the stretch wrappers. “When we planned this facility, we expected to use Lantech's automatic overhead stretch wrappers because we already had 15 of them at the time,” says Anthes.
“We are required to wrap these loads to the pallet by a major home center customer, and a lifting table is needed for the film payout to get below the deck of the pallet,” Anthes explains. The lift table is costly on the front end, and no matter how well it's made, it's going to be a maintenance issue.”Seeking an alternative
Anthes brought this to the attention of xpedx, his supplier of machines and film. The manufacturer's engineers introduced him to the then-new Pallet Grip option by Lantech for wrapping loads to pallets. The patent-pending system effectively attaches a load to the pallet with bottom wraps of film that have been twisted into a cable along the lower 4 to 6 inches of the web. The system costs less than 20% of a lift table's cost, which can run $10,000 or more. Basalite already had 15 such lift tables.
The film cable is wrapped to the pallet with 50% higher wrap force as it is secured below the deck, while the remaining film web stays above the deck and secures the load. Machines equipped with the system maintain a full 250% stretch to ensure lowest operating cost, so there's no film penalty. The force-to-pallet containment is set with the wrap force control on the machine, and the machine also controls the amount of the film web twisted into cable.
“Pallet-Grip leaves the forklift through-holes open, which makes more sense because load containment is the goal,” says Anthes. “If you wrap the load to the pallet using a lift table, the forks will puncture the film. This degrades the containment force and can allow the film to flap around in the wind. The Pallet Grip option would save us the cost and ongoing maintenance for the lift tables, and gives us better containment of the loads.”