Have you mastered the basics, but still have a picking bottleneck? Well, you aren't alone. Along with accurate inventory, productive picking is key to an efficient warehouse and satisfied customers. After all, as Modern featured last month in “Order picking basics,” those cartons and pallets aren't going to move themselves. If you want to get your product out the door, someone does have to pick it. And to get that job done, most facilities rely on picking fundamentals: WMS -, RF- and voice-enabled picking by an operator on foot or lift truck.

But facilities that need to improve productivity may turn to automated and semi-automated materials handling technologies, according to Craig Bertorello, vice president of operations for TriFactor (800-507-4209, www.trifactor.com). “In general, you're going to look at advanced picking technologies when you have excessive travel time, when you need to accommodate dense storage to make the most of your footprint, or when you want real-time management of a significant number of SKUs,” says Bertorello. “To determine which technologies are best, you need to look at the size of the products you're picking and the profile of your orders.”

One way to improve picking productivity is to add hardware and software applications that extend the capabilities of a warehouse management system (WMS).

Pick-to-light: Like voice technology, light-directed picking increases productivity because it's hands-free. Instead of hand-held scanners, flashing lights along the shelves direct order pickers to pick locations. These also display the number of units to be picked from a case. “With pick-to-light, you will generally see productivity increases, improvements in order quality and reduced errors,” says Hamilton Bitely, vice president of marketing for Speas Tech (888-377-6766, www.speastech.com). As a general rule, lights are best in medium- to high-volume operations with medium- to high-moving SKUs. The more dense the picking area, the more cost-effective it is to install pick-to-light. “In the right situation, you can get a 50% gain in productivity by going to pick-to-light,” says Bill Hubacek, director of order fulfillment products at FKI Logistex (877-935-4564, www.fkilogistex.com).

Multi-modal: While not in widespread use, multi-modal technologies are emerging as an answer to picking productivity improvements. While traditional devices are limited to one function, like voice or bar code scanning, a multi-modal solution allows a picker to seamlessly choose between voice, bar code scanning or manual input without having to switch from one software application to another. “The key is not just having a multi-modal device, but having multi-modal software,” says Mike Markham, vice president of sales for Cadre Technologies (866-252-2373, www.cadretech.com).

Software: Task interleaving is a software application that directs workers based on the three P's of picking: priority, proximity and permissions. “The idea is to minimize the amount of travel between tasks,” says Jim Le Tart, director of marketing for RedPrairie (800-990-9632, www.redprairie.com). “When a lift truck driver delivers a pallet to replenish the line, the next task might be to pick up an empty pallet at the line and return it to be replenished.” Task interleaving can deliver 15 to 20% improvements in productivity. Still, not everyone uses the functionality. “It requires a whole different way of working and a different mind-set,” says Le Tart.

Slotting: Warehouse and distribution center managers looking for more productivity may be overlooking the one solution staring at them every time they look at their pick faces: slotting.

Put simply, slotting is the science behind determining the best locations to store individual products to enable the most efficient picking. The general rule is that the fastest movers should be located closest to the shipping area, and in the easiest picking locations within an area.

Sounds simple. The problem is that once a distribution center has been slotted, too many managers never ask if their order profiles have changed. Maybe the fast movers are now the slow movers; maybe items now located in pick faces up front should be in reserve storage in the back. “The best companies are constantly looking at where their products are stored, and at what is the best technology for picking each SKU,” says Bill Casey, president and COO of SI Systems (610-252-7321, www.sihs.com). “It could be that an item in a pick-to-light area is more popular and ought to be in a carousel or an automated A-frame.”

Slotting applications calculate which items will be picked most frequently and should be in the most advantageous position in the warehouse. In addition, the tool will make recommendations like putting the heaviest items at chest height to avoid back injuries or to separate similar parts to avoid picking errors. “You're trying to reduce the amount of travel a picker does to move the orders,” says RedPrairie's Le Tart.

To make the most out of slotting, Le Tart adds, the system should be integrated with a labor management program. “A labor management program will calculate the cost of moving the material from one location to another, along with the potential labor savings from more efficient picking,” he says. “That way, you can determine whether the savings from more efficient picking outweighs the costs associated with moving the product.”

In addition to licensed applications, Web-based slotting tools can help, adds Casey. “A user can enter their warehouse data over the Web and the tool will deliver a report in a matter of minutes,” he says.

WMS- and light-directed solutions still involve sending an operator to a picking location. The next step to increased efficiency is using automated storage technologies to deliver the goods to the person. “The idea is that instead of a person going out into the warehouse to get the goods, we're going to take all of the stock picking units, put them in a high-density storage device, and then use that machine to deliver the goods to the person,” says Ken Ruehrdanz, market development manager for Dematic (877-725-7500, www.dematic.com).

Two types of automated storage systems are most common in goods-to-the-person picking applications.

Carousels: Vertical and horizontal carousels provide dense storage for cartons and small-to-medium size parts. What's more, carousels eliminate operator travel time by rotating to deliver the part to the operator. “Carousels are most often integrated with pick-to-light technology,” says Ed Romaine, vice president of marketing for Remstar (800-639-5805, www.remstar.com). “With one pod of carousels and one operator, you can pick up to 750 lines per hour.”

Automated storage and retrieval systems (AS/RS): Like carousels, unit-load and case-handling mini-load AS/RS systems provide dense storage in a small footprint. And like carousels, they deliver the goods to a picker, providing real-time control of inventory and eliminating travel time. AS/RS systems also enable dynamic slotting: Rather than many picking locations dedicated to an SKU, the warehouse control system can dynamically deliver product to available locations, reducing the space required for picking locations. “These systems not only improve picking productivity, they also enable automatic replenishment of a pick space,” says FKI's Hubacek. “That allows me to do dynamic reslotting and get my faster-moving items in the golden picking zone.”

Pick-to-light and goods-to-the-person picking still involve people working on the floor. For companies that want to take operators out of the equation, A-frames work like high-speed industrial Pez dispensers to provide fully automated picking. A-frames work best in environments with a limited number of high-volume, fast-moving SKUs with a consistent size. Product is dispensed onto belt conveyors or totes as they pass beneath the units.

“Usually, you're talking about the top 20% of the SKUs in terms of volume,” says SI Systems' Casey. A-frames are also best suited to small items with a consistent size and shape, like lipstick and cosmetics, pharmaceuticals, and DVDs or CDs. “You don't want more than 100 pounds of product in a unit, and you typically don't want a product that's larger than 12 inches wide by 12 inches long,” says Casey.

While none of these technologies is a one-size-fits-all solution—you're most likely to see pick-to-light, carousels, AS/RS and A-frames used in conjunction with traditional picking—each can improve productivity, throughput and accuracy in the right situation.