Many warehouses and fulfillment operations are being stress-tested as a result of COVID-19. If your warehouse is laid out in a classic aisle pattern, your fulfillment efforts may not be as efficient as they could be leveraging fishbones.
Your warehouse layout directly affects efficiency
In my 30+ years as a supply chain operations consultant, I’ve seen many half-hearted efforts made to get layout and slotting right, especially when initially configuring a warehouse. In particular, bin shelving is almost always laid out in a typical serpentine layout. Slotting may or may not incorporate attempts to treat higher velocity SKUs differently from low-velocity goods. It seems the default slotting technique is to position higher-velocity goods on lower shelves and lower velocity goods on the upper ones, sometimes only accessible with a ladder.
These efforts do provide some level of higher efficiency by reducing the effort required to pick high-velocity stock. However, the limited efficiencies achieved by these simple arrangements are lost due to unnecessarily increasing travel distances overall.
Most companies have a large number of slow-moving and no-moving SKUs that, in terms of fulfillment, mostly serve to lengthen the travel required during the picking process. Treat these items differently to achieve lasting slotting efficiencies. Fishbone warehouse layout configurations effectively separate slow-moving items from their fast-moving counterparts to minimize travel.
Fishbone layouts explained
In a fishbone arrangement, you have a few primary travel aisles and a series of adjacent secondary aisles – the fishbones – that you only go down if you need one of the SKUs located there. The “bones” are stocked so that higher-velocity items are located at the end of the row, near one of the main travel aisles. Slowest- and zero-movement stock is located further away from the primary aisles, eliminating the need to even travel down them unless you are picking one of those SKUs. Every secondary aisle that you don’t have to go down represents time saved compared to a warehouse arranged in a traditional fashion. Fishbones are particularly useful in an environment with a high number of slow-moving SKUs. (You can combine a fishbone configuration with a multiple-order, batch-pick process for even greater efficiencies.)
Fishbones speed things up substantially
Let’s put these travel savings into context using some relatively simple math. Assume you have 25,000 SKUs. Each SKU requires one foot of shelf space, and if you have five items on a shelf and a total of five shelves in a section, you would need 1,000 bays of rack space. Since racks share an aisle, the pick area’s total potential travel space is 2,500 linear feet. If you have to traverse just half of that distance per order and pick 400 orders in a day, you will end up traveling 500,000 feet. At three miles per hour, that’s 31 hours of walking time, much of it spent walking by SKUs that are seldom picked unless you make different layout accommodations based on velocity.
Now, let’s strip out the SKUs that make up 90% of your picking activity. You would likely have an easily accessible serpentine layout with 5,000 SKUs that would require 200 bays of rack and a corresponding 500 feet of travel, significantly reducing the walking time needed to pick these fast-movers. The fishbone created specifically for the slow-moving items still contains the remaining 2,000 feet of aisle, but now you mainly travel the primary aisle and only go down a secondary aisle only if you need one of the slow-moving SKUs kept there.
Travel less, fulfill more
Faster order fulfillment means reduced person-hours and lower costs. Evaluate changes in SKU velocities and adjust slotting as needed to maintain peak efficiency. Fishbones can be more than last night’s leftovers.
A dynamic slotting approach to warehouse design is the first step towards improving order fulfillment cycle time. Chainalytics’ combination of top supply chain talent, proven methodologies, and exclusive market intelligence consistently puts our clients ahead of the curve. Reach out to us to learn how Chainalytics’ experienced supply chain operations strategists can help you supercharge your fulfillment operations.
Stephen Bartolotta is a principal in Chainalytics’ Supply Chain Operations practice. He has more than 30 years’ experience leading transformative supply chain strategy engagements in warehouse design and operations, inventory management, transportation, and business strategy.
