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Focus on: Logistics


As convenience store operator Wawa expanded, it faced a logistics challenge: The company was adding more new stores, and its manually operated chilled warehouse had run out of room. Its production had outpaced its storage capacity, and the chain’s products were now being produced, staged on the warehouse floor and quickly shipped to make room for milk, teas and juices that were newly coming off the line. The distribution center’s storage space had surpassed maximum capacity.

“The challenge was where to put the product,” said David Mann, manager of Wawa’s beverage warehouse. “Where do you store it? Basically, the plant would produce to ship. It wouldn’t ever produce more than could be shipped over the next day. There wasn’t any more room on the floor to stage it.”

Wawa solved its dilemma with a highly automated storage and retrieval system that was engineered and installed by Swisslog Warehouse and Distribution Solutions, Newport News, Va. The high-bay refrigerated warehouse is serviced by 16 high-speed, fully automated storage and retrieval mini-load stacker cranes that efficiently move crates in and out of the 35-vertical-foot, high-bay racking.

The system receives crates filled with milk, teas and juices from upstream production, stores up to 80,000 crates in the system, then selects and releases crates to fill pick orders for shipping — all with no human intervention.

Switching from a manual to an automated high-bay chilled facility provided Wawa with the key benefit of maximized building volume and increased cost efficiency since the high-bay can handle a greater number of crates on a much smaller footprint. Also, the reduced footprint is an important factor in energy savings since much of the cold loss in a chilled warehouse occurs through the roof

Wawa’s high-bay optimizes cubic space usage via its vertical stacking capability and also by minimizing aisle cubic footage. By eliminating the need for forklift trucks, aisles can be made significantly narrower — allowing 12-ft.-wide aisles to become just 5-ft.-wide. This space can then be used for more crate positions.

WMS: The direct integration of the warehouse management system, supplied by Swisslog, ensures that Wawa’s mini-load stacker cranes always select the correct inventory and item numbers, which rotates the product inventory properly.

“Everything that we operate in the warehouse is driven by the WMS,” Mann said, “from the moment the products come off the production line, through storage and through shipping.”

The WMS knows precisely what the product SKUs are and how many of those crates are entered into storage. The integrated WMS ensures optimized storage for Wawa by distributing SKUs over its 16 aisles, improving delivery execution and maximizing labor resources.

The WMS is integrated with Wawa’s ERP to monitor and streamline orders automatically straight through to shipping. The facility can automatically handle 42,000 crates of liquid products daily (2,400/hr), operating with a system uptime rate exceeding 99%, and an order accuracy rate topping 99.9%.

“The high-bay and automation has enabled us to do larger runs,” explained Mann. “And we do fewer runs of product because of the additional storage.”

The automated solution, which operates 20 hours per day, six days a week, has had ongoing upgrades since it was put into operation

“After many years of usage, the Swisslog mini-loads and WMS are still performing very well,” Mann said. “We have done numerous upgrades on the systems. The uptime on the equipment is outstanding.”

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