Why Your Material Handling System May Not Be Performing As Expected

By Greg Chaffee, Vice President of Systems Sales and DirectPick™

Integrated order fulfillment systems are the result of careful planning and countless hours of analysis and design. A major step in this process is understanding your universe of SKUs in terms of the frequency of hits and the associated cubic velocity. How often an item is picked and replenished is a key factor influencing the performance of your overall system.

During the design of a new system, significant effort is put into capturing the data required to do a full analysis and develop the best possible solution. Information is gathered in a variety of areas, including order and item activity profiles, forecasted expectations, material flow volumes by operation, personnel by work area and labor statistics.

Once a thorough analysis has been completed, a system layout is developed within the constraints of the available real estate. SKU assignment (slotting), is a natural part of this all encompassing process. Slotting is always a key factor in the proper execution of a new Greenfield or major retrofit project, but the major challenge is the regular application of its principals in day-to-day operations. I like to refer to this as product life cycle slotting.

There are many variables that determine where a given SKU should be slotted within a system. From a picker’s point of view, they want to move as little as possible while making the greatest number of picks. From a systems and replenishment point of view, you want to assign a SKU to the technology that best suits its activity and cubic velocity.

Too often, systems do not receive the proper attention on a scheduled basis for SKU or item slotting maintenance. If a motor was not running properly, would you check it out and do the proper maintenance? Of course you would. If a bearing was squealing, would you replace it or re-grease it? Absolutely.

However, if a SKU has increased its frequency of hits and its cubic velocity, but is still being picked from the top shelf in a flow rack or carousel, would you know to re-slot the SKU to a more appropriate location, where it could be picked more efficiently? Not necessarily. A lack of slotting maintenance could silently be killing your system.

A typical product life cycle slotting history may cover a broad range of picking technologies and placements. There may be an initial product launch which includes full cases being picked from pallets or flow rack. It may eventually evolve to open case picking from flow rack, carousels, or shelving. It may also involve seasonal characteristics which require the re-slotting of a SKU on a periodic basis.

In all cases, a slotting exercise should include an A,B,C mover analysis within the bounds of the given technology or subsystem that the SKU is currently assigned. In other words, if a product is slotted in a flow rack pick to light area, the “A” movers will be assigned to the most ergonomically pleasant shelf levels or the “golden zone” for picking. The “B” movers will be more likely accommodated in the shelves below. And, the “C” movers will be in the higher shelves.

What will happen if you neglect your slotting maintenance? Some of the most frequent down falls are:

• Greater replenishment to the forward pick location due to a mismatch of the velocity requirements of the SKU and the technology
• Slower picking and ergonomic discomfort because SKUs are not placed in the proper A,B,C location within a technology
• Low probability of multiple hits within a zone because SKUs are not placed within family groups
• Bottlenecks and inefficiencies due to unbalanced workloads across zones

Because we are acutely aware of the slotting challenge in the initial design phase and as a regular maintenance activity, Diamond Phoenix offers a slotting module in the DiamondWare Warehouse Execution System WES 3.0™. This module is designed to provide an easily understood SKU activity history which enables planners to see changes in activity with SKUs and within zones, subsystems, and complete fulfillment systems.

We encourage you to take a more pronounced look at your slotting maintenance. By applying proper slotting techniques on a regular basis, you will reap the benefits, including higher picking productivity, more efficient replenishment procedures, increased worker enjoyment and safety, and a greater continuing return on investment.