When the plastic bottle manufacturer Southeastern Container started producing injection molded preforms at its Enka, N.C. plant, only one fork truck was needed to serve the plant's two production lines.

A lot has changed since then. Today, the company has expanded its operations to 24 production lines and installed larger, more efficient machines, which take up even more floor space. With increased production and tighter aisles came the need for a new materials handling solution. The five or six fork trucks necessary to handle all the lines simply would not be able to navigate the plant safely and efficiently in its new configuration.

That's when Southeastern turned to automation. It replaced the fork trucks with six automatic guided vehicles (AGVs), improving product movement.

Southeastern Container is one of the United States' largest PET bottle producers. Seven plants serve various bottlers throughout the country, transforming injection molded preforms into plastic bottles for Coca-Cola and other bottlers. The Enka facility produces many pallet loads of bottles ranging from ½-liter to 3-liters on each shift. The compact preforms also vary greatly in size according to the size of the intended finished product. That makes flexibility crucial to the plant's materials handling process.

"Preform production lines are constantly changing to accommodate production needs for the other Southeastern facilities," says Peter Falcigno, technical manager for Southeastern Container. The plant's wire-guided AGVs effectively react to these changes by handling pallets and containers of various sizes and weights.

Preforms are placed into two types of containers depending on their final destination. About 35% go into all-plastic containers and remain in-house for the blow molding process. The remaining preforms are placed in corrugated containers set on plastic pallets and are shipped to other facilities for final production. The containers, measuring 48 × 40 × 48 inches, weigh between 675 and 1,000 pounds, depending on the preform's size.

When production lines quickly change between in-house and export preforms, the AGVs must immediately change pallet type or route. "The AGVs are instrumental to keeping operations running smoothly in the plant," says Falcigno. "The vehicles are constantly moving throughout the plant, either delivering empty containers or moving full container loads to the warehouse. Navigation is reliable and safe as the systems follow their designated path."

The AGV's microprocessor-based control system uses traffic routing AGV command executor (TRACE) software to maximize traffic flow on the plant floor and prevent vehicle collisions. The control board allows operators to view and modify moves at any time with a simple "point-and-click." Its user interface displays AGV, load and stationary equipment status, and movement in real-time.

"With the AGV systems, we now have perfectly orchestrated vehicle movement between all production stages and that's resulted in increased productivity," says Falcigno.