October 1, 2005
equipment & applications | Containers & Storage

Just one word: plastic

The cardboard box may be the traditional way to store and transport items. But that doesn't mean it's the best way.

By David Maloney

When something needs to be moved or stored in or around the DC, most people grab a box—a corrugated carton. A mainstay of shipping operations everywhere, the familiar six-sided carton can be used for an endless variety of applications. But it's not necessarily the best choice. For all its virtues, the corrugated cardboard box has drawbacks too: it's an easy target for thieves, it's easily pierced or crushed, it's prone to snagging when used in automated handling operations, it requires disposal after use. That's why more and more operations are bypassing cardboard for an alternative that has none of these shortcomings: the returnable plastic container.

It's not hard to understand why returnables are making headway in the container market. Most commonly made of plastic (though they can be made of wood or metal), returnable containers trump cardboard in a number of ways, their advocates say: They reduce purchasing and disposal costs. They offer a higher level of security. They offer better ergonomics. And they do a better job of cubing out space.

Better still, they're versatile. Returnables come in designs and sizes to fit just about any application. Large bulk containers, for example, can be used for transporting large items (or a multitude of small items) or for storing products in racks. They're typically designed with fork entries to allow easy transport via lift trucks or pallet jacks. And many times these containers offer hinged side doors that, when lowered, allow easy access to the items inside. Many bulk containers also come with collapsible sidewalls so that they can be easily stored or transported when empty.

Smaller containers are typically designed so that when placed side by side, they match the footprint of a standard 40- by 48-inch pallet. They offer a wide range of stacking configurations, and most are designed with top and bottom grooves to facilitate stacking into solid cubes that can max out available space in storage racks or on trucks. Top covers—and sometimes straps—hold the load together during transit for a secure ride.

Safe and secure
Returnables easily outperform their corrugated counterparts when it comes to product protection, according to plastic container manufacturers. Most returnable containers used for shipping offer hinged lids to help protect the products placed inside. Typically, they're also designed to accommodate security cable ties that loop through the lid and a hole in the container's sidewall. This locks the lid in place and discourages theft of the contents. A broken tie provides an easy method of identifying containers that may have been breached. And because they are made of sturdy plastic, which resists piercing or crumpling, these containers also tend to protect products better than corrugated cartons can.

Most returnable containers are also designed to stack one on top of another to save floor space. Turn one container 180 degrees in the opposite direction and it can be inserted into the empty tote below it for dense stacking. This "nesting" feature allows a large number of empty totes to occupy a small space in storage racks or for transit back to the facility.

Because plastic containers come in uniform sizes, they're ideal for use with automated material handling systems. They're also the container of choice for automated mini-load systems and carousels because, unlike corrugated cartons, they have no rough edges that can snag when used in automated systems. Further, they can be easily transported on conveyors and sorting systems.

Plastic containers are also designed to work well with the latest in inventory control technology. Most are designed with special areas on their outside panels to accommodate bar-code labels and RFID tags. These areas are recessed so that conveyors or other material handling equipment will not tear the tags as they move through the distribution operations.

Easy on the back
Plastic returnable containers also offer ergonomic advantages over cardboard cartons, according to plastic crate manufacturers. Easy-to-grip handles on the plastic containers' ends make them much easier to lift and move than corrugated cartons. And their uniform size helps ensure that loads don't exceed weight limits. Many companies will designate specific sizes of containers for certain classes of products, knowing exactly how many items can be picked into the containers before they reach a maximum threshold for safe lifting.

Since plastic containers can be made in virtually any color, some facilities designate certain colors to represent the various functions within the distribution facility. Red may be reserved for picking tasks, while a green container may signify that the items inside are destined for a value-added service station.

Taking advantage of this, some of the more sophisticated conveyor systems have sensors built in that are able to distinguish colors. Pickers completing a wave of orders may pick the last products into, say, a yellow container to signal that this completes the wave. Once the container is sent off to the sorting equipment, the sensor identifies the yellow tote as the last tote to be diverted to a particular spur line.

Closing the loop
By their very nature, plastic containers must be reused again to be cost effective. Because of this, most reusable containers in use at distribution centers are used exclusively within the facilities. But that's not always the case. Some companies have developed distribution systems that call for their containers to be shipped out to stores and select customers. These, however, must have some mechanism for returning the containers to the distribution center for reuse. Companies operating such closed-loop systems often ship the containers on their own dedicated fleet (see sidebar). Filled totes are dropped off at delivery and empties are gathered for the return trip back to the DC.

Pooled container programs offer an alternative for those companies wishing to use reusable containers but that don't operate under a closed-loop distribution model. With pooled programs, the containers are owned by the pooling company. The pooler takes responsibility for retrieving the empty containers, washing them and delivering fresh empties to the distribution centers.

The best thing about returnable containers is that they can be used over and over again, making them extremely cost effective.When they do reach the end of their lives following hundreds of trips, they can be recycled easily, which also makes them a sound environmental choice.

About the Author

David Maloney
Editorial Director
David Maloney has been a journalist for more than 35 years and is currently the editorial director for DC Velocity and Supply Chain Quarterly magazines. In this role, he is responsible for the editorial content of both brands of Agile Business Media. Dave joined DC Velocity in April of 2004. Prior to that, he was a senior editor for Modern Materials Handling magazine. Dave also has extensive experience as a broadcast journalist. Before writing for supply chain publications, he was a journalist, television producer and director in Pittsburgh. Dave combines a background of reporting on logistics with his video production experience to bring new opportunities to DC Velocity readers, including web videos highlighting top distribution and logistics facilities, webcasts and other cross-media projects. He continues to live and work in the Pittsburgh area.

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