Getting the right e-commerce fulfillment center design

Put systems can achieve phenomenal throughput rates, and are both scalable and flexible.

By -- Modern Materials Handling, 4/1/2000

The right design. It's what will make or break an e-commerce fulfillment center. But how do you know what best matches your requirements, current and future? And just as important , how do you go about making sure that you are following the right decision making path?

In a nutshell, start by developing a thorough model of the center's profiles, inventory levels, supplier capabilities, and delivery requirements to meet consumer needs. Then study the fundamentals of fulfillment center design-first principles. Follow this with an analysis and evaluation of how these basic design approaches apply to your specific requirements both now and for the forseeable future.

Here is an overview of three design approaches likely to be considered in your deliberations. The upside and downside of each approach is mentioned too.

Order selector/packer

In this approach, the order selection and packing functions are performed by the same person. The smart cart displays multiple totes corresponding to orders. This allows the operator to batch pick and pack orders matched to the practical limitation of cart size.

A benefit favoring this approach is that it can be brought on stream quickly and is inherently flexible. The downside includes limitations on operation productivity (long travel distances limit productivity). In addition, scalability is limited for high-volume requirements.

Put system

In this approach, picking and packing are decoupled in a manner that facilitates both functions to maximize productivity. For instance, an entire day' s order requirements could be aggregated and the day's demand picked by item. It could then be temporarily held in an automated buffer that would meter out the items to "put stations" where operators would "put" (pack) multiple orders at each station.

The benefit of this approach is that productivity in the picking function (generally the most labor-intensive task) can achieve phenomenal rates. The concept is scaleable and flexible. The downside is that attention to design details must be adhered to because this concept is less forgiving if poorly conceived.

Pick, sort and pack

In high-volume centers where this approach is used, picking and packing are linked by sortation technology. On the pick side of the sorter, multiple induction stations meter product onto the sorter, which directs the items to designated packout stations. Some limited buffering ahead of induction and at the packout stations allows a slight imbalance between picking and packing unlike the put system where these functions are purposely decoupled. Typically, this design breaks down the day' s demand into time slots known as waves; say, 2 hours of work to take advantage of multiple order selection within each wave.

Next month's column will expand on "put system" concepts . . .an excellent way to achieve very high performance and one that is likely to gain considerable attention in the e-fulfillment world.