Food maker automates storage/retrieval in cold warehouse

The typical cold-storage warehouse in the U.S. is a large, cavernous building with ceilings approximately 20 ft high and multiple 12-ft-wide aisles with forktrucks riding in and out of them, moving product up and down from the racks. The temperature in these warehouses is typically a chilly -10 deg F, cold enough to keep food products safely stored, but an extreme environment that makes work difficult and has considerable negative impacts on production. Compared to nonfreezer facilities, cold-storage warehouses have a higher incidence of product damage, missed product rotation and wrong-item fulfillment. Not surprisingly, personnel turnover in cold-storage facilities is also higher than in nonfreezer warehouses.

Cold-storage warehouses pose definite challenges to operations and logistics managers, who endeavor to have facilities operating at a high level of efficiency. Where a 99th percentile inventory and fulfillment accuracy rate could be expected in a nonfreezer warehouse, it becomes unrealistic at -10 deg F below zero, that is, unless the warehouse has an automated storage and retrieval system (AS/RS) in place. An AS/RS is a computer-controlled system that automatically deposits, retrieves and inventories loads from defined storage locations. It allows inventory to be moved quickly, safely and precisely in a warehouse environment. When applied to a subzero warehouse, an AS/RS produces dramatic results, effectively making the cold-storage facility as efficient as an automated nonfreezer warehouse, according to Joe Maas, vp of operations at J.T.M. Food Group, Harrison, OH.

High bay accessibility

Another major benefit for a company switching from a manual to an AS/RS cold-storage facility is high-bay accessibility. In a typical cold-storage warehouse where forklifts are used, the lift's maximum reach is about 20 ft, which allows 4 vertical pallet positions. An AS/RS facility commonly has as many as 12 vertical pallet positions on racks that are 80 ft high or more.

In a nonfreezer warehouse, this increased height is an important efficiency factor in reducing the footprint of the facility. In a cold-storage warehouse, however, the footprint reduction becomes an absolutely critical factor in energy savings, because much of the heat gain occurs through the roof. In effect, cold-storage warehouses are giant insulated freezers that extract heat to produce a cold environment. This removal of heat comes at a hefty energy cost, which, incidentally, is significantly more than what it takes to merely heat a space. Because of its smaller footprint, a cold-storage warehouse with an AS/RS can handle the same number of pallets as a manual facility with one-third of the energy cost. That was the case with J.T.M., which made the switch from a manual cold-storage facility to one incorporating an AS/RS.

J.T.M. is a family-owned food processor producing such products as meatballs, sausage links, pork chorizo, beef stroganoff, turkey à la king, cream of broccoli soup and hoagie buns. All of the company's products are cooked, packaged and distributed from its own plant. Since the late 1960s, when the company first operated as a modest retail meat shop in Cincinnati, it has grown exponentially into a prominent meat processor with sales in 2007 exceeding $72 million. The company manufactures more than 1,000 items, all of which are frozen. Half of the company's products go to school-lunch programs, while 35 percent go to restaurants and 15 percent go to supermarkets and grocery stores locally.

Like most other meat processors inventorying frozen product, J.T.M. struggled for years with the limitations of inefficient cold-storage facilities, exacerbated by the company's continual need for more storage space fueled by its expansive growth.

“We had been building new storage freezers every couple of years, since we started the business,” says Maas. “We were operating with two 700-pallet storage freezers and using outside storage, and we wanted to increase our efficiency by consolidating the freezers into one space and manage our entire inventory internally on location at the plant.

“Taking up land space was another problem that we were trying to overcome,” he continues. “Freezers are quite expensive to build and operate, so we wanted to minimize aisle space, which is dead space. We tried to come up with ways to minimize aisle cubic footage, so as to maximize pallet positions and make it more reasonable to build.”

Forklifts are another problem with ordinary freezers. “Not only do forklifts let out a tremendous amount of cold air from the freezer, they also do a lot of damage to the racking, doors and product,” says Maas. “So another goal of mine was to get rid of forklifts on my shipping and receiving docks. I wanted to design a freezer that was as efficient as possible, and be operated by as few people as possible. I looked extensively, and found the automated pallet-storage-and-retrieval system.”

Double-load AS/RS

To meet its needs, J.T.M. constructed a 20,000-sq-ft, -10-deg F cold-storage warehouse with 10,000 high-bay pallet locations serviced by an AS/RS. “We were getting tired of the same size and type of storage freezers, so this time, we built a really big one with 10,000 pallet locations that would take care of our needs for many years,” says Maas. J.T.M. selected Dematic Corp. (www.dematic.us) to design and build the storage and retrieval system, including control software, racking and associated conveying equipment. Dematic designed the system with a unique double-load, remote pallet-handling device that can carry 2 pallets at a time, instead of an AS/RS machine that handles 1 pallet at a time.

Thus, when J.T.M.'s AS/RS machine picks up two loads that are coming out of manufacturing, it decreases the cycle time of the machine and increases throughput.

Deep-lane storage

When the pallet is on the pallet-handling device, it is carried off of the AS/RS machine into a rack, in a function called deep-lane storage. When the AS/RS machine runs up and down the aisle, it handles 4-deep pallet-storage lanes on one side, and 8-deep pallet-storage lanes on the other side. A conventional AS/RS machine only goes 1-, 2- or 3-pallets deep, using a fork attached to the machine, because that is the maximum it can reach. The Dematic drive-off remote can run a pallet 30 ft into the 8-deep side and drop it into storage, and then return back to the AS/RS machine.

“J.T.M. can do an entire production run of hamburger patties that are all the same lot and the same SKU, for example,” says Mike Khodl of Dematic. “So, they can store 8-pallets-deep and still access the same lot number and the same run of product. One of the key aspects of the project was that Dematic designed the order-picking stations outside of the freezer environment. This has really reduced turnover because people used to this job inside the freezer.”

“Dematic also integrated StagingDirector™ for inventory management and pallet movement with the AS/RS” explains Khodl. This is part of the Dematic Warehouse Control System information technology suite. When J.T.M. gives StagingDirector an order, it knows where it stored that palletized SKU and it goes in and gets it and brings it out to a workstation. J.T.M. personnel then pick off the cases they need to fulfill the order. The pallet then goes back into the system, which knows where to put it. It also knows how many cases are left on that pallet after the cases are picked off. This information then is integrated into J.T.M.'s order-management system. StagingDirector has visualization screens that give personnel the ability to immediately look into what level of inventory they have in their facility.”

More energy efficient

The AS/RS eliminated the excess air exchange in and out of the freezer, making it more efficient at reducing energy costs. “The roof square footage with an AS/RS is small,” Maas says. “Most of our cold loss is going to occur in the roof, so the AS/RS design minimizes that. It has a single, extremely narrow, 5-ft wide-aisle as opposed to several 12-ft-wide aisles on non-AS/RS freezers. Also, there are no large doors that open. The doors are smaller, and they only open when product needs to go in and out, and only for as long as necessary to take in a pallet. Then they immediately shut automatically behind the pallet.

“Our AS/RS doors are 6 ft high and 4 ft wide, which is the size of the pallet, so when the pallet is passing through the door, it blocks air from getting out. Then the door shuts immediately.” Maas adds that a standard freezer with a forklift has an 8x10 ft opening, and the door closes slowly, sometime after the truck passes through, releasing a lot of cold air.

The AS/RS also eliminated J.T.M.'s maintenance costs for forklifts and the labor and travel time associated with physically operating them. Now, J.T.M.'s order pickers are more efficient and more productive. They simply push a button and out come the SKUs they need, and they pick right to the order pallet. Overall, the AS/RS reduced warehouse labor by 75 percent and cut energy usage by 66 percent.

“My refrigeration engineer shakes his head every time we look at the freezer,” says Maas. “It uses one-third of the refrigeration we felt it was going to need, based on our prior experience with nonAS/RS freezers that hold 10,000 pallets and based on everything we knew before. We originally installed two compressors, but only one of them ever comes on because the other is not needed.”

J.T.M. built the freezer big enough so it could rent out the additional space until it is needed, so the company does third-party retail-logistics work out of its freezer. It has all of its own product, as well as the other company's product in its freezer. This has made it much more affordable for a smaller company like J.T.M. to take advantage of this level of automation.

Another benefit of the AS/RS is the security of the product in the freezer. “Our level of security is incredible,” says Maas. “Because no one goes in the freezer, the products are more secure from pilferage and tampering, and there is zero product damage and zero rack damage. Inventory issues were abounding before, but now our inventory is always correct. The AS/RS always gets the correct item number, and it always rotates the product properly. Our order fulfillment was in the mid- to high-90-percent range, but it has gone to more than 99 percent since we put the AS/RS in place.”