Attacking the picking problem

By evaluating three areas of order picking—set up, travel time and the process—you can minimize the time you spend picking.

By Bob Trebilcock, Editor at Large -- Modern Materials Handling, 8/18/2008

Implementing best order-picking processes can be boiled down to how a facility optimizes three elements: set up, travel time and the picking process itself.

“The goal of any order-picking process is to minimize the time spent picking,” explains Kevin Hume, director of consulting services, TranSystems | ESYNC. “If you think about order picking in those three buckets, you can see where you’re spending the most time and use that data to get your biggest improvement.”

Set up: Set up is the process of getting the information about the work you’re about to do, and then preparing for the work. In batch picking, for instance, that might involve getting totes, the labels for the totes and the picking orders. “You’ll typically see more set up time with sophisticated picking processes, like zone picking or pick and pass, where you’re working on multiple orders at a time,” says Hume. “The idea is that the investment in set up time reduces travel time later on. But you have to account for the set up time.”

Travel time: Next, you’re looking for an average travel time across locations for all picks. “Once you get an average picking time, you can look at ways to reduce travel time,” says Hume. “For instance, does it make sense to put the highest velocity items in a forward pick location, even if you increase travel time for the slow movers.” Remember, Hume adds, reslotting may require technology and equipment, like lift trucks, walkies or conveyor, to retrieve and transport the slow-moving items. 

Picking: The third element is the picking process itself. “You want to represent the picking process in mathematical terms,” Hume says. “That’s the time it takes to identify the picking location, pull the product and place it in a tote, container or carton, or on a pallet.”

In addition, there’s a technology tradeoff to the picking process. That might be the comparison between what it costs to manually confirm orders and correct errors versus the cost of a warehouse management and radio frequency communication system to direct picking.           

Once each of the elements has been evaluated, Hume says, you can compare various picking methods to determine which methodologies fit best your volumes over a planning horizon that’s important to your business.