Planning for picking? Pick your plan

Consumers have been spoiled by competing supply chain managers. A combination of technology and constantly improving practices has taught the public to want things fast, good, and cheap! At the same time, a tough economy has taught supply chain managers to seek a competitive advantage by applying advanced material handling and logistics systems that reduce labor, speed delivery, and increase accuracy.

Since order-picking is typically the area representing one of the largest labor components, material handling systems manufacturers have focused their offerings on integrated systems which reduce human travel and the number of touches associated with picking. In a book my firm was commissioned to author for the Warehousing Education & Research Council (www.WERC.org) entitled, “Pick This! - A Compendium of Piece-Picking Process Alternatives,” we identify and explore 567 piece-picking process alternatives. The sheer volume of differing approaches warrants detailed data analysis and a thorough understanding of goals and objectives before embarking on any picking automation initiative. After all, if you apply automation to a bad process, bad things happen faster.

Pick system automation is tried and true and solutions have been deployed effectively in Europe for decades. European warehousing, distribution, and fulfillment operators embraced these technologies earlier than practitioners in the United States, largely because of their higher labor and land costs and because their economic policies encourage long-term capital investment.

Further fueling the case for automation is the global trend towards higher SKU counts, smaller orders with higher frequency, compressed order cycle time requirements, and a plethora of value-added services which add cost to every order processed.

Not just for the high-margined

Contrary to conventional wisdom, the application of integrated mechanized and automated systems in Europe is not evidenced only in high-tech, high-margin business sectors such as pharmaceuticals, medical, life sciences, semiconductors, precision optics, or advanced ceramics companies.

During a recent trip to Spain, I visited a two-million square foot supermarket distribution facility, which housed one of the most highly automated operations in the world. The installation consisted of more than two-hundred Automatic Storage & Retrieval System (AS/RS) cranes operating in dry, refrigerated, and frozen environments.

An AS/RS is essentially a high-rise rack or shelving system with long, very narrow aisles in which a crane travels horizontally down the aisle on a floor mounted and overhead rail system. The crane is equipped with a carriage mechanism that travels vertically on the crane mast and inserts or extracts unit loads from either side of the aisle automatically. A Warehouse Control System (WCS) keeps track of the location of each SKU and instructs the machine where and when to operate.

In this grocery operation, homogeneous pallet loads (single SKU) are received at the loading dock, their bar-code license plates are scanned, and then the pallet loads are placed on pallet conveyor stations which induct them into the AS/RS where they remain in the proper temperature controlled environment until needed for picking.

When that particular SKU is needed to fulfill order demand, the pallet is automatically extracted by the AS/RS crane and delivered to a de-layering station where an overhead suction device lifts one layer of cases off the pallet. The layer is then deposited onto a wide array of interleaved conveyor belt sections which “singulate” them, forming a train of cases on a narrow belt.

As each case approached the end of the conveyor, it cascades gently onto a low-profile “slave tray” (a uniform plastic carrier) which is fed by an automatic tray de-stacker. Now that each case is traveling in slave trays, it can be inducted into a “mini-load” AS/RS machine which randomly stores each case of product (on its slave tray) in its correct temperature zone.

Once all of the SKUs needed to complete a particular wave of orders reside in the mini-load system, the discrete order picking cycle begins. SKUs (cases) for a particular order pallet are extracted automatically by the system and delivered to an automatic palletizing system which computed the best possible layer and interlocking patterns for the wide variety of case dimensions and weights. The empty slave trays are delivered to an automatic stacker, queuing them for use once again. Once palletized, the unit load is automatically stretch wrapped, labeled, and delivered to the shipping dock in the lane corresponding to the outbound tractor trailer (in reverse stop sequence).