Pros and Cons of Overlapping Waves for Picking
Warehouses, distribution centers, and other order fulfillment operations looking to boost efficiency and productivity often begin by thinking about the role that automated technology—like sorters, AS/RS, and robotics—might play in their facility.
Automation is a powerful tool, and for most operations there will be a tremendous opportunity to automate tasks in order to boost efficiency. But it is not the only path toward progress. It’s also important to ensure that your operation’s workflows and processes are optimized, especially when it comes to the most-time consuming and repetitive of tasks.
Case in point: Order picking.
For many operations, order picking is a labor-intensive process that accounts for the vast majority of wasted walk and search/travel time workers spend passing 99.9% of your inventory to pick the correct items within your facility. Additionally, the specific order picking strategy that you leverage will impact other processes within your operation, for better or worse. Leveraging the wrong strategy could lead to reduced order accuracy and bottlenecks, reducing your efficiencies.
While wave picking gets a lot of attention when it comes to order picking strategies, it is far from the only option available to you. Another order fulfillment strategy that is becoming increasingly popular is overlapping waves.
Below is a look at overlapping waves in picking, the benefits that it has to offer, and a discussion of alternative approaches so that you can make a more informed decision about what is best for your business.
Got questions about how to leverage overlapping waves in your facility? Speak with a member of the Conveyco Team!
What are overlapping waves in picking?
The easiest way to understand what overlapping waves are in picking is to compare the strategy directly to wave picking, as they are related forms of order processing.
In wave picking, orders are grouped into waves. When a wave begins, a picker receives their pick list and then works through their zone in order to pick the items required. As items from each order are picked, they are sorted, consolidated, packed, and sent to shipping. Following this strategy, the wave must be completed before the next wave can begin. This leads to a period of inefficiency between waves.
Overlapping waves, on the other hand, is a variation of your traditional wave picking that provides a more consistent throughput and labor utilization. When an operation leverages overlapping waves, the idea is to release the next wave before the last wave has begun to lose efficiency. Once the first wave reaches its peak and begins to become less productive, the next wave is released, and so on. The end result is that the entire operation is able to maintain a higher level of productivity, with less intense valleys and peaks compared to wave picking. (see the graph below for a simple demonstration).
Benefits of Overlapping Waves
The primary benefit of leveraging overlapping waves is that it “levels out” the productivity of an operation and eliminates the efficiency declines. This keeps the peaks and declines even by raising the valleys, ensuring that high levels of productivity remain within a narrow and predictable band. The end result is reduced labor demands and improved equipment utilization for the entire operation.
Alternatives to Overlapping Waves in Picking
The two primary alternatives to overlapping waves are wave picking (discussed above) and waveless picking.
In waveless order picking, batches are dynamic and constantly changing. As older orders are completed, new orders are constantly added into the batch. Once a worker completes one pick, the system automatically checks to identify the next optimal pick location and routes them to that spot. The result of waveless picking is similar to that of overlapping waves: A leveling out of the peaks and valleys in productivity that an operation experiences. That being said, it often results in performance that is lower than overlapping waves.
Waveless order picking has been leveraged heavily in retail, ecommerce and omnichannel applications where there is a lot of pressure for same- and next-day shipping. Overlapping wave picking improves waveless performance.
Which Strategy is Right for You? Wave, Waveless, Overlapping Wave
Wave, waveless, and overlapping waves can each be an appropriate strategy, depending on the specific requirements of your operation. While the overlapping waves method has some clear benefits for the right operation, there is no one size fits all approach that states it will be the best choice in all circumstances.
That being said, if you are looking to improve your organization’s equipment and labor performance, overlapping waves might be the solution for your operations. It’s critical that you have selected a WES that can support the strategy. Better yet will be to select a WES that can change and adapt alongside your business as it grows and evolves over time.
If you would like a no-obligation consult as to which strategy makes the most sense for your needs, speaking with a trusted systems integrator and WES provider can help you understand your options. Contact us today to speak with a member of the Conveyco Team.