"Goods to person" puts a different spin on order picking
In some of today's high-tech warehouses, workers no longer trudge up and down aisles to fill orders. Sophisticated machines deliver everything they need right to their stations.
Back in the day, there was one thing about order fulfillment operations you could pretty much take for granted. When it came to gathering items for orders, the people did the walking and the equipment stayed put.
That's no longer a safe assumption. Today, a growing number of companies are taking the opposite tack. Instead of sending workers out to retrieve goods, they're using automated material handling equipment to deliver items to order pickers who remain in a fixed spot. This approach, known as goods to person, isn't new. In fact, it's been around for several decades. But it's attracting increased attention these days, particularly from high-volume operations that do a lot of piece picking.
What's driving much of the interest in this approach is its potential to enhance productivity. Suppliers of goods-to-person systems say the equipment can boost pick rates as high as 1,000 lines per hour. Part of the reason is that workers spend less time traveling and more time order picking, making them more productive. Another part is that automated systems offer capabilities like product sequencing that help streamline the work flow.
There are other benefits as well. For one thing, these systems save space. Goods-to-person setups allow for denser storage and eliminate the need for traditional pick faces, reducing overall storage space requirements. For another, they boost accuracy. With goods-to-person systems, only the goods needed for orders are delivered to operators, cutting down on the chances workers will pick the wrong items.
Other advantages include improved ergonomics and safety. Under this approach, workers no longer have to carry cases from place to place; the storage machines and conveyors do the heavy lifting. In addition, lift truck traffic is reduced, resulting in a safer work environment.
As for equipment, goods-to-person systems come in a variety of forms and configurations. They can incorporate pallet-based (unit load) automated storage and retrieval systems (AS/RS), tote-based miniload systems, carousels (both horizontal and vertical), robots, and vertical lift modules. (For purposes of this story, we'll concentrate on automated storage and retrieval systems, both pallet- and tote-based.)
To date, goods-to-person picking has been successfully employed in a range of industries, including retail, pharmaceutical, grocery, apparel, industrial parts, meat, dairy, and medical. What follows are four examples of companies that have successfully adopted this approach.
When it needed to boost logistics productivity, Next, one of the United Kingdom's largest clothing retailers, decided to give goods-to-person picking a go. It installed an AS/RS that is connected to high-rate put stations at its DC in South Elmsall, England. The gambit paid off. Once the new system was in place, picking productivity increased by 300 percent.
The system, which was supplied by Dematic, stores fast-moving apparel items, footwear, accessories, and home goods. When needed for orders, products are automatically retrieved and conveyed to one of the system's 20 put stations. Within each station, 24 order totes are staged, each representing a different store.
Workers follow a light-directed process to select items and place them into the proper totes. The remaining product is then sent back to the storage system until needed. Completed orders are pushed off onto takeaway conveyors that whisk them to shipping.
The result is a fast, productive system for filling store orders. Workers are able to pick up to 1,000 items per hour, which is three times the rate achieved back when they had to search the shelves for products.
Like Next PLC, Liberty Hardware saw productivity soar when it shifted to a goods-to-person picking approach. In September 2009, Liberty installed an automated AS/RS from Daifuku at one of its distribution facilities in Winston-Salem, N.C. The one-aisle miniload system, which boasts 3,520 storage locations, holds cabinet hardware, wall plates, and other items in totes. These items are picked as individual pieces, mainly to fill specialty and online orders.
Liberty made the switch in a bid to boost efficiency and make better use of space. Under the old system, employees picked products from flow racks in a traditional pick module onto carts—a method that required a lot of walking.
"The big issue for us was travel time. This eliminates it," says Tom Turner, Liberty Hardware's vice president of global logistics. "[The new system] also allows us to fit a larger amount of stored product into a smaller footprint."
When needed for orders, totes holding hardware are retrieved by crane and deposited on a conveyor for transport to a picking station. Once the selections have been made, the items are conveyed to pack stations, where they're placed into cartons for shipment. To maximize efficiency, the system allows up to 12 orders to be filled at a time.
Among other benefits, the new system has improved order accuracy. Because only the items needed for orders are delivered to the stations, accuracy now stands at better than 99 percent. The system offers security advantages as well, since only the storage/retrieval machine can access the product totes.
But the biggest gains of all have come in productivity and labor savings. With the new system, Liberty is able to fill about 80 orders an hour, a very high rate for complicated piece picking, and it does it with fewer people. "We have been able to reduce our labor over 50 percent from the old-style methodology," reports Turner.
Spar AG, one of Europe's largest grocery chains, has done more than just pay lip service to the goods-to-person approach. It has backed up its words with cash, investing heavily in automated storage systems for its distribution center in Wels, Austria. The 900,000-square-foot facility, which holds both dry food and non-food items, serves 1,500 stores, most of which are small shops that handle less-than-case quantities.
The facility boasts a number of automated systems supplied by TGW Systems and Witron. They include a high-bay AS/RS system for storing pallets, Witron's Dynamic Picking System for less-than-case quantity selection, Witron's Ergonomic-Dynamic Picking System for picking cases, and another AS/RS miniload system to sequence shipping.
The high-bay AS/RS consists of 17,500 locations and eight aisles, and primarily replenishes the other automated picking systems.
The Dynamic Picking System is a goods-to-person system used for split-case picking, with products dynamically delivered to a picking face. Products are stored in totes in miniload aisles. The bottom of the system has a large number of facings where the totes are brought for picking. Lights direct picking from the delivered totes into order totes. The product totes continuously change position as they are retrieved and placed into the facing, then sent back to storage after picking has been completed.
The Ergonomic-Dynamic Picking System, which is used for selecting full cases, puts a different spin on fulfillment. Workers are automatically transported to pick locations, riding through aisles on six crane carts that move horizontally or vertically to positions holding 800 different stock-keeping units (SKUs) that ship as full cases. Upon arrival at a picking location, the worker selects the required case and deposits it onto an order pallet, which adjusts up and down automatically to a comfortable height for picking. The worker then pushes a button and the cart whisks him to the next pick location until the pallet is complete.
A fourth AS/RS acts as a shipping buffer. It contains 11 aisles to hold totes filled with picked products until they're ready to ship. It then releases them in sequence to a stacker that gathers the totes onto wheeled carts for shipment. Upon delivery to stores, the carts are simply wheeled into shop aisles to make restocking shelves easy.
Idaho State Liquor Division
Not every facility is able to invest in a full goods-to-person picking system, but that doesn't mean it can't benefit from the technology. Distribution operations can still realize big gains by using AS/RS systems for tasks like replenishment.
A case in point is the Idaho State Liquor Division, which is completing the installation of a three-aisle AS/RS system that will be used to replenish storage racks in its Boise DC. The AS/RS, which holds more than 3,000 pallets in double-deep racks, will solve a sticky storage problem for the liquor distributor. For some time, the Boise facility, which supplies spirits and liquor to 166 state-owned or -contracted stores, has been grappling with a shortage of capacity. Installing the AS/RS system, which was supplied by Interlake Mecalux, will allow it to store most of its reserve inventory in just 17,000 square feet of floor space.
Once the system is up and running, pallets will be discharged at a floor-level station that will be used to replenish forward case picking locations on the bottom levels of the existing static storage rack. A second output station is located on an upper mezzanine. Pallets for split-case picking will be delivered to this station, where cases will be removed from the pallets and conveyed to the back of flow racks. The cases will then be made ready for split-case picking.
"We are going to touch the product less often," says Bill Applegate, the facility's product general manager. "Just in all ways, we'll have a lot denser product storage, and we'll be freeing up space in the original warehouse for either lower-volume items or to create more picking locations. Our plan is for this AS/RS to meet our needs today and as much as 25 years in the future."
About the Author
David Maloney has been a journalist for more than 35 years and is currently the editorial director for DC Velocity and Supply Chain Quarterly magazines. In this role, he is responsible for the editorial content of both brands of Agile Business Media. Dave joined DC Velocity in April of 2004. Prior to that, he was a senior editor for Modern Materials Handling magazine. Dave also has extensive experience as a broadcast journalist. Before writing for supply chain publications, he was a journalist, television producer and director in Pittsburgh. Dave combines a background of reporting on logistics with his video production experience to bring new opportunities to DC Velocity readers, including web videos highlighting top distribution and logistics facilities, webcasts and other cross-media projects. He continues to live and work in the Pittsburgh area.
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