Full automation of materials handling in a warehouse exists only in the imagination of the technocrat. Just as the perfectly-safe airplane is too heavy to fly, the fully-automated warehouse is too expensive to buy and usually too risky to operate.

An inverse correlation exists between mechanization and flexibility. There have been many instances of conveyor systems being sold for scrap because there was no resale market for this specialized equipment. Today, robotics and improved warehouse management systems are now enabling an increase in automation with systems that have reasonable flexibility.

The driving stimulus for warehouse automation has always been an effort to save space or labor. In rare instances, the system will save both.

Many of the earliest efforts to automate concentrated on saving space. In 1975, the first International Conference on Automation in Warehousing was held in England. Most of the presentations described stacker cranes, movable racks and narrow-aisle mobile equipment. In densely populated Europe and Asia, space has always had a higher value than in America.

Today, a shortage of qualified workers is a pervasive stimulus for increased automation of materials handling. Naturally, the most labor-intensive tasks are the first targets. Picking orders requires the greatest amount of travel, and therefore the greatest amount of time spent per item handled. Unfortunately, many of the systems that mechanize order filling also reduce flexibility in doing this job.

Another automation stimulus is the shortage of truck drivers and the increasing cost of motor freight. Systems that will expedite the unloading and loading of trucks will generate more interest as shippers seek to control the cost of motor freight by eliminating warehouse delays.

While warehousing in multistory buildings is increasingly rare in the U.S., we still occasionally see such facilities in use. Vertical conveyors will greatly reduce the cost of materials handling, as compared to the conventional freight elevator.

Here are five different approaches to automation in materials handling:

1. Pick-to-light flow rack systems have now been in use for more than three decades. LEDs (light emitting diodes) in front of each rack lane tell the picker how many cases of each item to select. Minimal training is needed for newcomers to become proficient in order selection.

2. Voice recognition systems eliminate paper and provide oral instruction, resulting in increased order picking productivity.

3. The A -Frame functions like a giant vending machine and drops the appropriate number of pieces into a tote bin. While the picking is automatic, replenishment of the bins is not.

4. Automatic truck-loading systems use rails or wheels on the trailer floor to move the entire load from trailer to dock.

5. Robots are employed to retrieve and deliver single units for kitting or repackaging.

In each of these cases, there are trade-offs in cost and flexibility.

While robots and blinking lights have great entertainment value, much can be achieved with a series of small improvements rather than an expensive leap into inflexible machinery.