DC Velocity - April 2014

techwatch

AS MORE LOGISTICS MANAGERS TURN TO AUTOMATION TO
boost distribution center (DC) productivity, many are finding that
the traditional solution isn’t working according to plan. Automated
warehouses typically have relied on two types of software in combi-
nation to oversee their operations—a warehouse management sys-
tem (WMS) and a warehouse control system (WCS). But that hasn’t
always proved to be an efficient approach. “When companies have
a ton of mechanization in the warehouse, the WMS has to integrate
into a warehouse control system,” says John Sidell, co-founder of
the firm New Course LLC. “As a result, the utilization of automated
material handling systems isn’t as effective as expected.”
To understand the problem, it helps to know
a little about how the situation evolved. WMS
solutions were originally developed to keep tabs
on inventory and oversee activities like receiving,
picking, and putaway. These solutions have proved
highly effective in manual or semiautomated oper-
ations. But when DCs install automated material
handling equipment—such as automated storage
and retrieval systems, pick-to-light systems, and
tilt tray sorters, to name a few—another “layer”
of information technology is needed: a warehouse
control system. The WCS essentially takes instruc-
tions from the WMS and then tells the equipment
what to do. “The WMS is really about managing
people,” says Marc Wulfraat, president of MWPVL
International Inc., “and the WCS is really about
managing machines.”
For many of the companies using a WMS in combination with a
WCS, the problems begin when they attempt to sequence and opti-
mize picking waves with their automated equipment. According to
Sidell, warehouse management systems are sufficient for planning
and executing manual pick waves. And in some cases, a WMS and
WCS combined can handle the execution of pick waves with auto-
mated material handling equipment. But oftentimes, he says, the pick
waves built by the WMS for execution by the WCS end up causing
slack time in parts of the operation, resulting in reduced efficiency for
the equipment and an overall slowdown in throughput.

As a result, Sidell says, companies are forced to heavily customize
the WCS to build pick waves for automated equipment and then use
the WMS only for processing manual pick orders. In fact, he told
me that he knows of companies that have purchased a brand name
WMS package only to restrict its use to inbound
shipments, directing activities like receiving, put-
away, and storage. When these companies have
orders to pick and ship, they shut off the WMS
and rely solely on the WCS to coordinate the
equipment needed to move product out the
door. “Many folks turn off the WMS on out-
bound and bolster the WCS to get the outbound
efficiencies,” says Sidell.

That’s why some companies are turning to a recently developed application, the warehouse execution system (WES), that replaces both the WMS and WCS. This type of system is offered by Forte, Knighted/ Intelligrated, and Reddwerks, among others.

A WES can both maintain the warehouse inventory records and drive the mechanization. Most importantly, WES “It’s really suited to heavily mechanized facilities that are pushing out huge volumes,” Sidell says.

Warehouse execution systems have attracted particular interest among retailers, many of whom are wrestling with the challenges of handling both direct-to-consumer fulfillment and store replenishment from a single DC. “The emergence of omnichannel retailing is putting even more pressure on the existing automated material handling equipment (AMHE) to function with higher levels of throughput and with a higher number of orders but lower order quantities,” Sidell says. “Retailers are heavy users of AMHE, so this makes them a great fit for WES.”