AS/RS Update

May 1, 2005
Equipment suppliers have been working hard on new machines that extend the capabilities of automated storage/retrieval systems.

AS/RS refers to various computer-controlled machines for automatically placing and retrieving loads from storage locations. It includes vertical carousels, horizontal carousels and vertical lift modules that have been fitted with automatic inserters and extractors, as well as cranein-aisle systems.

Historically, pallet handling AS/RS installations relied upon precision racking systems, and a telescoping platen, rather than a pair of forks, to place a load on two load arms. The racking in such systems can be expensive, and difficult to reconfigure when products and pallet sizes change. A new rotating fork machine from HK Systems (Milwaukee) uses standard post and beam rack, reports Mike Kotecki, senior vice president. Even though it has a maximum height of 40 ft.—compared to more than 100 ft. for some AS/RS installations—standard racking is cheaper and more flexible. Using a rack and gear system, the machine will shift and rotate a load simultaneously. On a cost of operation basis, it was designed to be competitive with manned very-narrow-aisle lift-truck applications.

To address maintenance concerns HK Systems engineers are designing machines with more off-the-shelf components. "Fifteen years ago it was all highly proprietary positioning devices and highly proprietary, custom made circuit boards that you did need to be a Ph.D. to diagnose," says Kotecki. "We're trying to take the cost of ownership down so it's comparable to owning a fork truck from a maintenance and reliability standpoint."

The ability to use standard shelving is one of the benefits made possible by new carton grippers developed by Siemens Logistics & Assembly Systems (Grand Rapids, Mich.). By grabbing and storing full cartons, the grippers also eliminate the need for "detrashing," the step of unloading cartons and loading the contents into standard-sized totes or bins prior to storage. Grippers are available for both single and double deep storage.

"For order fulfillment applications, AS/RS continues to see applications that utilize the goods to the person principle," says Ken Ruehrdanz, business and development manager for Siemens. "The AS/RS retrieves a pallet (unit load AS/RS) or tote (mini-load AS/RS) from a location in the AS/RS and serves it up to a person who will pick cases from the pallet. When the pick is complete, the AS/RS returns the load back to storage."

This approach can be used to manage the proliferation of SKUs that warehouses and distribution centers are now handling, he adds. Medium-and slowmoving items can be stored up high and retrieved when needed by an AS/RS and presented to a temporary pick face, rather than maintain a pick face for every SKU in the warehouse.

Addressing the installation and easeof-maintenance issue, Diamond Phoenix Corp. (Lewiston, Maine) has developed controls technology that enables them to deliver carousel systems cheaper, and install and integrate them faster. A recent refrigerated installation for the beef industry, reports Larry Strayhorn, president, consisted of 56 carousels and 18 robotic inserter/extractors. They were able to install, test, commission and turn the system over to the customer in just 30 days. The control systems also feature remote diagnostic capabilities.

"We've gone to complete bus controls and intelligent controllers on the machines," says Strayhorn. "The drives can be programmed remotely. They're managed remotely."

Flexibility and throughput are the two biggest demands from AS/RS customers today, reports Ken Matson, executive vice president for FKI Logistics (St. Louis, Mo.). Both are supported by new load handlers and developments in sortation logic.

"We have the ability, because of the load handler flexibility, to pick up three totes and deliver them to three different locations," says Matson. "The locations they are delivered to are based on where they need to be located within the route truck. Later, when the truck arrives, we can go to individual lanes and pull all three totes and deliver them in a sequence that matches the truck."

AS/RS flexibility and throughput are also aided by the ability of cranes to change aisles, which more customers are specifying according to Matson. Whether they follow a wire in the floor or a rail, the ability to switch aisles increases redundancy should a crane go out of service. This also allows cranes to be serviced in a special maintenance area, which has special appeal in cold-storage facilities. This aisle-changing ability adds another layer of complexity to what are already very sophisticated, fast moving machines.