What is Wave Picking?

Wave picking is a type of picking method that combines multiple orders and schedules them to be picked at the most appropriate time of the day. This group of orders to be released is called a “wave,” and they are grouped and scheduled using the following considerations:

-Shipping schedules

-Replenishment cycles (Ensures that pick faces are sufficient before scheduling waves)

-Shift changes & available workforce

-Product locations and commonality (Grouping products to maximize efficiency and reduce travel time)

-Carriers

-Priorities

By grouping and scheduling orders using the conditions above, you can effectively utilize your resources and avoid bottlenecks.

How Does Wave Picking Work?

Pre-Wave Picking

Before wave picking occurs, waves need to be scheduled. Using a warehouse management system (WMS) is advised to speed up the process because of the numerous variables involved when building the waves.

As orders come in the warehouse, the WMS reads all order details and logically groups and schedules them to be picked in the most appropriate time. And to get maximum productivity, orders may need to be stockpiled until there are enough similar orders to create the waves.

Performing Wave Picking

Many sources about wave picking vary because there are many ways to implement it. Wave picking can be merged with batch picking, cluster picking, or zone picking. But the commonality is that orders are grouped into waves and the schedule needs to be followed strictly. The way to execute your waves will be dependent on your type of warehouse, the inventory you hold, and the orders you get.

Here’s a scenario of how wave picking in its simplest way can occur:

"A warehouse received a group of orders that are bound to be shipped in a single trailer at 11 am. The WMS will then group them into a wave and execute them with enough lead time before shipment. The amount of lead time will depend on your resources and average picking, packing, and shipping time, which can all be calculated through a WMS. The program also ensures that orders have sufficient stock. In the case that you don’t have a WMS, it can be done manually but takes more time to schedule waves correctly."

Post-Wave Picking

If batch or zone picking is used in conjunction with wave, the time to segregate items into orders would need to be included in the lead time.

Pros and Cons of Wave Picking

Pros:

1. On-Time Shipments

Because wave picking takes into consideration shipping schedules and resources available, waves are released or executed with an estimated lead time before shippers or carriers depart.

2. Reduced Bottlenecks

When waves are formed, product location, labor resources, and equipment are taken into consideration. This ensures that the over-allocation of people and equipment on a single aisle does not happen, freeing operations from congestions and bottlenecks.

3. Reduced Travel Time / Reduced Cost

The reason why waves need to accumulate similar orders is so that the warehouse can reduce the amount of travel per picker. Picking multiple items per SKU or picking items near each other can significantly decrease travel time, in other words, cost.

4. Increased Accuracy

In the case of wave picking combined with zone and batch picking, it allows for a second check on product codes and quantity. Picking and sorting are separate processes when zone or batch picking is used, therefore increasing accuracy.

The nature of the methodologies where picking and sorting are separate processes, therefore allowing for a second check.

5. Suitable for High-Security or Fresh Goods

Because orders are picked just in time before shipment, high-security or fresh goods can have less idle time.

Cons:

1. Potential for Downtime

If labor and resources are not equally distributed in waves, downtimes can potentially occur. Because waves are executed sequentially, workers and equipment need to wait for the current wave to finish before moving on to the next wave.

2. Unable to Accommodate Emergency Picks

Once a wave is established and executed, it is tough to accommodate emergency, high priority, or same-day picks without resorting to very manual processes. And because each wave is designed to maximize all resources, executing waves simultaneously is not efficient.

Wave picking is an effective way to utilize resources correctly and without bottlenecks. This method is useful in large scale operations where workers can bump into each other because of limited regulations when operating.