A good defense takes a solid distribution offense

A 78,000 SQUARE-FOOT HIGH-BAY STORAGE ADDITION TO THE U.S. MILITARY'S LARGEST DISTRIBUTION CENTER ASSURES THAT SERVICE UNITS WORLDWIDE ARE WELL SUPPLIED.

By -- Modern Materials Handling, 3/1/2001

Napoleon Bonaparte once observed that an army marches on its stomach. He astutely recognized just how important supply lines are to soldiers in the field. That same principal is just as important today. Keeping military units stocked and ready, wherever in the world they may be, is a critical component of America's defense initiatives.

Providing fulfillment for U.S. military units worldwide is a daunting task. Two large distribution centers located in Pennsylvania and California split distribution efforts. The West Coast facility serves the western half of the U.S. and Pacific Rim bases. The larger Eastern Distribution Center is known as DDSP-Distribution Depot, Susquehanna, Pennsylvania. Located along the Susquehanna River in New Cumberland, Pa., the DDSP provides for military units in the eastern U.S., Southwest Asia, Europe, North Africa, South America, and Central America.

Susquehanna, near Harrisburg, has been used as a military depot since 1918. The 848-acre site contains about 30 outlying warehouses and a huge 1.7 million sq. ft. distribution center.

"We provide distribution support for all branches of the U.S. services, anything an army can use except fuels and munitions," says Bob Skinnell, industrial engineer with the Defense Logistics Agency, the logistics arm of the Department of Defense.

Since most military bases function as their own small cities, Susquehanna must provide everything a community needs. This includes clothing, medical supplies, vehicle parts, recreational equipment, and office supplies.

Some of these items, such as tires, clothing, and hazardous materials are stored in dedicated buildings on the grounds. The most active items are stored in the central DC, which was built in 1990 and was first tested in action during the mobilization for Desert Storm just 10 years ago.

This past September, a $10 million, 78,000 sq. ft. expansion was completed on the DC's high-bay storage area. The Army Corp of Engineers oversaw construction.

Another $4.4 million was spent on upgrading materials handling systems. New semi-automatic reach trucks were purchased to work the aisles of the rack-supported storage building, and new conveyors for moving pallets and cartons were added. Modifications were also made to an extensive tow line conveyor system, with a spur extended to reach new pallet loading stations. Additional spurs and some rerouting of the system also accommodates a new active bulk storage area.

"The way we do business has changed so much since we opened 10 years ago," says Skinnell, who says they used to do more consolidated shipments for domestic military orders, but are now shipping fewer products more often. "We also have made significant improvements in our ability to keep our most active products in this one building," he adds.

Product flow has additionally improved with replenishment pallets now brought closer to order processing. Throughput and storage capacities are also greater, which has allowed the Department of Defense to bring into the DC faster-moving materials that had been held at a Mechanicsburg, Pa., Naval installation, less than 9 miles away. That warehouse has now been freed for other uses.

Additionally, the new storage machines in the high-bay area (Cleco Systems, www.clecosys.com ) are 30% more efficient at moving materials in and out of locations than the previous units.

The center now musters; a 67-aisle, high-bay area, two tilt-tray sorters, a 5-mile tow conveyor system sporting its own army of over 1,200 carriers, a large split-case pick module, 4.5 miles of other conveyors, and an automated manifest identification system used primarily for shipments heading overseas. The facility can fill 50,000 orders daily.

"What this building does is give us the best combination of speed and flow," says Jackie Noble, command affairs officer. "The automation and technology we put into the facility really have helped us manage the flow."

The increased throughput capability additionally allows the center to meet its mission of 1 day processing, something that the DC moved to about 3 years ago. What had previously taken up to 3 days for high-priority orders and 7 days for routine items now is completed in one.

The central Pennsylvania location near several interstates also delivers products quickly to domestic bases.

"We can reach two-thirds of the U.S. with a 2-day truck ride," observes Noble. "It is centrally located, which is very strategic for us."

Digging in

Most of the workers at the Eastern Distribution Center are civilians. Occasionally reservists are brought in for training so they will be ready to assist during military emergencies.

There are two major types of receipts arriving at the DC-new products from a wide range of commercial vendors, and returns coming back from various military field units.

Advance ship notices are sent for most of the new products that arrive at the 54 docks. Commercial freight and parcel carriers are typically used for transport. Pallet loads of products are transferred to carts pulled by the extensive tow conveyor system. Individual cases under 40 lb are prepared for parcel conveyor transport. Oversize items are staged on the floor or are sent to one of the outlying warehouses for storage. Some trailers containing full loads will ship inventory as is within the same trailers. These remain in the yard until dispatched.

Vendors are required to bar code receipts to ease entry into the facility's warehouse management system (WMS). Some of the returns from the field require repackaging and the addition of a bar code by receiving personnel.

The DDSP has a unique, fully portable receiving station that aids the processing of incoming pallets and cartons. A small pushcart contains a bar code scanner linked by radio frequency to the WMS, a printer for producing tracking labels, and batteries to keep everything operational for 8 hours.

The worker simply walks along the rows of tow carts loaded with pallets, scanning each pallet and cart ID to enter the product into the system. Each cart is then released to the in-floor tow conveyor. Scanners in the floor read the cart IDs and direct the product to its proper destination.

About half of pallet load receipts are crossdocked to a consolidation area where items are gathered for overseas shipments. The remaining 50% enter storage. Individual cases are conveyed either to the flow racks of the walk-and-pick area or to bin storage, where they will be added to current stock.

The tow conveyor takes most of the non-crossdocked pallet loads to either the large high-bay storage area (fast movers), or to the pallet rack area (slow movers).

Thirteen new aisles were added to the high-bay storage area in the recent upgrade. Semi-automatic, man-up reach trucks patrol the 290 ft-long, 65 ft-high aisles. Thirty-two aisles encompass the rack-supported building divided into three, fire-walled sections. The bottom level of the high-bay area is actually constructed about 10 feet below the facility's main floor. This is due to building height limits imposed because the DC is in the flight path of a municipal airport located next door.

The tow carts drop off receipts at a transfer station while the system summons the high-bay truck for putaway. On-board wireless terminals communicate putaway locations. The driver has the option of driving manually to the location, or by pushing two buttons, the system will automatically move the vehicle along the most efficient route.

Round 'em up, move 'em out

Military units from all over the world requisition needed supplies from the Defense Logistics Agency, which consolidates orders and releases them to the DDSP. The objective of the facility is to "do today's work today," with most orders shipped within 24 hours. Priority items are processed first followed by routine orders in six daily waves.

Full trailer loads that are stored in the yard and ship as is are released when their cabs arrive for transport. Other orders are filled with inventory from the various areas of the DC and outlying warehouses. Full pallets come from staging and storage areas. Large cartons and mixed pallets that combine items from pallet storage come from the high-bay area, flow-rack picking, bin shelving, and items crossdocked from receiving.

Reach truck drivers use pick tickets to direct the selection of case items from the high-bay storage area. The operator scans the ticket, which identifies the appropriate storage location. Once there, the driver pulls the needed cases by hand, scanning each carton and location bar code to confirm proper selection.

The cases are then delivered to a pallet conveyor located on the end of the aisles. The conveyor takes these pallets to a transfer station where the loads are placed on tow carts for transport to a number of possible destinations - shipping, replenishment of the active-pick flow racks, or tilt tray sorters to accumulate overseas shipments.

The active pick area, also known as walk-and-pick, handles fast movers stored in flow racks with a unique packing system that was designed in house. Moveable work stations containing packing supplies and a printer are attached by rails to the face of the flow racks. The pack stations slide back and forth along the pick face to the area where selections are required.

"The system has eliminated the need to stop at a separate pack station for most of our fast moving materials," explains Skinnell.

Pick tickets also direct fulfillment here. Workers first scan the ticket along with the location bar code of the product. Each item is additionally scanned and then bagged using the packing materials on the sliding work stations. A bar code is printed and applied to the bag. The operator then simply turns around and places the bagged items on a conveyor that runs though the middle of the module. The conveyed bags travel to a station where they are placed in a tote.

The tote is further conveyed to an automated weigh station. Items are next conveyed to a sliding shoe sorter for delivery to outbound shipping lanes. The lane destinations are determined according to carrier and route.

Overseas processing

A large quantity of products flowing through the DDSP distribution center are earmarked for units overseas. These include hundreds of individual destinations, some of which are units that are currently on the move and away from their normal base of operations.

Items for these end users are pulled from the various storage areas and sorted by two tilt tray units. The sorters' 368 chutes accumulate materials for each designated military unit or address. The chutes can be reassigned for each wave of sorting. As items drop from the trays into the chutes, workers scan each item, and place it into large bulk shipping cartons attached to pallets. The carton also has a bar code ID that is scanned. Once filled, the carton is dropped by lift truck onto a tow cart for transport to an overseas processing area.

The unit load is weighed, banded for ease of transport, and a packing list added. Also attached is a radio frequency identification tag for tracking, and an automated manifest system (AMS) card. The AMS card can be immediately read upon overseas receipt, revealing the carton's entire contents.

Each pallet load is configured to fit the dimensions of specific air transport planes. The loads are next staged for shipping by over-the-road carrier. Some additional supplies from the outlying warehouses are also brought to the staging areas to join the outgoing goods from the distribution center.

Most of these outgoing materials are trucked to Dover Air Force Base for flights to overseas destinations in Europe, Africa, South and Central America. Once there, military vehicles and some commercial carriers, such as Fed Ex, deliver the supplies to individual bases and military units.

Fine tuning

Skinnell says the facility is now being fine-tuned to take advantage of the new systems. The high-bay addition has only been functional since last Fall, and products are still being placed within it. Skinnell adds that he wants to make sure that the right products, only those that are the fastest movers, are being stored in the DC as opposed to one of the outlying warehouses.

While it is a little early to get a true read on all of the positives resulting from the upgrade, improvements attained already have only added to the respect the DC has as the top facility of its kind anywhere.

"This is the largest and most technically-advanced automated warehouse within the public trust," says Noble. "This building really is the crown jewel of the Department of Defense."

System Snapshot

Department of Defense

Eastern Distribution Center

Susquehanna, Penn.

Site first used as depot: 1918

Distribution center constructed: 1990

Upgrade completed: 2000

Facility size: 1.7 million sq ft

Size of upgrade: 78,000 sq ft

Stock keeping units: 691,000

Employees: 1,744

Inventory: $5.5 billion

Throughput: 20,000 orders/day peak

System suppliers High bay storage and system integration:

Cleco Systems, 770-795-9077, www.clecosys.com

Conveyors:

Hytrol Conveyor Co., 870-935-3700, www.hytrol.com

Tow line conveyor, tilt tray system:

SI Handling Systems, 610-252-7321, www.sihs.com

Sliding shoe sorter:

Buschman, 513-874-0788, www.buschmanco.com

Racks:

Frazier Industrial Co., 908-876-3001, www.frazier.com; Unarco Material Handling, 615-384-3531, www.unarcorack.com

Flow racks, additional conveyors:

Interlake Material Handling, 630-245-8800, www.interlake.com

Lift trucks:

Yale Materials Handling Corp., 252-931-5535, www.yale.com ; Hyster Co., 252-931-5100, www.hysterusa.com ; Crown Equipment Co., 419-629-2311, www.crown.com

Additional high bay vehicles:

Raymond Corp., 607-656-2311, www.raymondcorp.com

RF system and scanners:

Symbol Technologies, 800-927-9626, www.symbol.com

Fixed scanners:

Accu-Sort Systems, 800-227-2633, www.accusort.com

Upgrade at a glance

• 78,000 sq ft high bay area added