May 1, 2006
equipment & applications | Pick to Light

Don't be blinded by the lights

don't be blinded by the lights

It's easy to be dazzled by the flashy colored lights in today's pick-to-light systems. But it's the software that separates the best from the rest.

By Bernie Knill

Let's get rid of the notion that pick-to-light systems start and end with lights. That might have been true 25 years ago when the technology was introduced, but not today.

What differentiates one system from another nowadays is the order fulfillment software. The lights just have to be reliable; the software is what really separates one system from another, says Bill Hubacek1, director of distribution products for FKI Logistex North America.

Hubacek advises customers to evaluate a system by its functionalities: Can it track a tote's contents? Pinpoint when an order was picked, by whom, and into which tote? Generate a packing list? Signal the system when replenishments are needed? Balance workloads to accommodate variations in workers' picking speeds? In short, can the software do what the customer requires?

Customers can be forgiven if they aren't sure exactly what they require. The last few years have seen an explosion in technological advances, leaving many confused about pick-to-light technology and its capabilities. To help clear up some of the uncertainty, we offer answers to a number of frequently asked questions.

Q: How does a pick-to-light system work?

A: A pick-to-light system uses lighted beacons, usually mounted on storage racks, to direct order picking activity. In a typical pick-to-light operation, a computer electronically reads order pick tickets, determines the best picking sequence and transmits signals to the light modules on the racks. Flashing lights then guide workers to the items they need and indicate the quantity needed. When he or she is finished, the order picker presses a button so that the computer can verify that the correct item has been picked.

Q: What are the benefits of using pick-to-light technology?

A: To begin with, there's productivity. By minimizing the time order pickers spend searching for the correct SKUs, pick-to-light technology can double or triple picking rates. That, in turn, typically translates into a reduction in labor requirements.

Then there's increased accuracy. The light-up displays make it virtually impossible to pick the wrong items. As a result, most DCs find that costs associated with returns and mispicks plummet soon after they install a pick-to-light system.

The systems are also easy to use. Pickers need only minimal training and a minimal command of the language, says Dave Broadfoot, managing partner at Lightning Pick Technologies. That's a big plus for DCs that use a lot of part-time workers or employees with limited English skills.

For an example of the results, you need look no further than East Coast Salon Services, a Runnemede, N.J.-based distributor of salon and beauty products. The company's order accuracy has soared to 99.98 percent and labor needs have dropped by half since it installed a Dematic pick-to-light system. Company officials also report that it now takes just 15 minutes to train new workers and that by the third day on the job, the average picker is able to pick 216 lines per hour and 648 pieces an hour.

Q: Is a pick-to-light system the same as a put-to-light system?

A: No. Although the two systems use the same hardware, a put-to-light system essentially works like pick to light in reverse. With pick to light, pickers with order totes fan out to retrieve items from the locations indicated by the flashing lights. With put to light, batch-picked items are instead delivered to stationary totes or bins used to collect items for an individual order. The light modules are located not at the SKUs' locations but at each order bin, telling the picker that, say, this tote needs six pink sweaters and that one needs three.

Q: What kind of software do pick-to-light systems use?

A: Many users choose to link their pick-to-light systems to their warehouse management software (WMS). But that's not the only option, says Brian Morley, vice president of Daifuku America Corp. Other possibilities include tying pick-to-light systems into a warehouse control system or a stand-alone system supplied by the pick-to-light vendor.

Q: Can a pick-to-light system be modified to accommodate changing needs?

A: Yes. They're designed to make it easy for companies to change pick zones or add more zones. In fact, many of today's systems come with modular snap-on light displays that can be swapped out in a heartbeat when a new product is introduced into a pick location. "Pick-to-light systems are flexible, based on day-to-day or week-to-week business needs," says Craig Welch, Daifuku America's manager of new product development. "Also, companies have the ability to dynamically slot product based on velocity."

If it turns out that a major overhaul is needed, suppliers will step in to help. "You're seeing a lot more upgrading, adding, changing, modifying," says Ed Romaine, director of marketing for Remstar International, which supplies pick-to-light systems. "Our current projects are all modifications."

Q: Isn't pick-to-light technology just for big companies?

A: Not any more. Prices have plummeted in the past few years, says Stephen Small, vice president of marketing and sales for Kingway. "When we first used to build these systems, they were built on a custom computer with its own operating system," he explains. "Since then, we've begun using servers that are a lot less expensive." He adds that the costs of manufacturing the lights have tumbled as well. Small claims that anybody with a couple hundred SKUs can afford to put in a pick-to-light system. "We're selling systems with 200 lights for under $l00,000," he says.

Q: How can I get a rough idea of the cost?

A: To estimate the cost, you first have to figure out how many lights you'll need. From there, it's a simple matter of multiplication. "From a budget standpoint, the industry uses a couple of hundred dollars a light as a ballpark figure," says Ken Ruehrdanz, business development manager for Dematic (formerly Siemens Dematic).

Q: Do I have to buy the components separately?

A: No. A number of suppliers offer all-inclusive packages. For example, GBI Sorters sells a turnkey system that includes the servers, pick modules, wiring, custom software and service, says Philip Sinnreich, systems sales consultant for the company.

Q: What are the most common mistakes made by companies buying pick-to-light systems?

A: One is planning for the present, not the future. "Anything you do in the warehouse has to be part of a plan," says Romaine of Remstar International. "It's important to anticipate what the [DC's through put] rate will be three years from now and design for it, matching the rates of all the components."

Another is assuming that the technology will sell itself to management based on its reputation for boosting productivity. "I think that pick to light requires some kind of justification," says Bob Carver, vice president of HK Systems. "Either that's going to be an economic or some other corporate justification—perhaps security or verification."

Q: What about maintenance and upkeep?

A: Maintenance is much simpler today than it was in the past, thanks to advances in diagnostic systems. "If a light fails, we have diagnostics that identify the light that is not responding," says Hubacek of FKI Logistex.

In addition, most suppliers offer maintenance contracts. Those contracts have become popular with customers. Today, about 80 percent of users have maintenance contracts.

Contracts are available for systems of all sizes. Prices range from just under $100,000 up to one and a half million dollars.

Q: I keep reading that RFID is the way of the future. How does RFID fit with pick to light?

A: Although there have been a limited number of installations to date, RFID is unquestionably moving into the realm of pick to light. As Broadfoot of Lightning Pick Technologies sees it, RFID is a natural fit with a technology like pick to light that's engineered to boost productivity.

For one thing, RFID frees order pickers' hands for other tasks. "With RFID, you eliminate the need for workers to use hand-held scanners," Broadfoot says. Another benefit is that workers no longer need to line up cartons for scanning. RFID doesn't require a line of sight for reading a tag. No matter which way the carton spins on the conveyor, the operator can still identify its contents.

1Due to a reporting error, Bill Hubacek was misidentified as Bill Subacek in an earlier version of this article.

About the Author

Bernie Knill
Guest Editor
Award-winning journalist Bernie Knill has been writing about material handling and logistics for more than 35 years. He can be reached at

More articles by Bernie Knill

Material Handling Videos

Join the Discussion

After you comment, click Post. If you're not already logged in, you will be asked to log in or register.

Subscribe to DC Velocity

Feedback: What did you think of this article? We'd like to hear from you. DC VELOCITY is committed to accuracy and clarity in the delivery of important and useful logistics and supply chain news and information. If you find anything in DC VELOCITY you feel is inaccurate or warrants further explanation, please ?Subject=Feedback - : don't be blinded by the lights">contact Chief Editor David Maloney. All comments are eligible for publication in the letters section of DC VELOCITY magazine. Please include you name and the name of the company or organization your work for.