As a warehouse supervisor or eCommerce business owner, you’re constantly looking for ways to cut costs and increase efficiency.
Especially as your warehouse scales, it’s critical to ensure you’re maximizing productivity, both from a personnel perspective and an order fulfillment perspective.
Wave picking is a powerful way to decrease your fulfillment time and go into each day with a concrete plan. It’s about getting away from reactive mode and into proactive mode.
If you’re tired of feeling like you’re constantly putting out proverbial fires in your warehouse, wave picking might be the best way forward.
First, let’s start with a basic definition.
What is Wave Picking?
Wave picking is a method of order fulfillment designed to solve a few specific problems.
The first problem is, “How do I prioritize my daily fulfillments so that it’s not complete chaos in my warehouse?” The second problem is, “How do I optimize my workforce so that there’s not inequality in responsibilities or wasted time?”
In other words, warehouse employees standing around, waiting to fulfill orders. These costly bottlenecks hinder the entire workflow of the operation.
But it’s not because they’re lazy. It’s because the order they need to process and fulfill is contingent upon someone else’s picking. And that person is halfway across the warehouse, inefficiently going back and forth from one corner of the warehouse to another to find items.
Then, a more substantial question arises. Should you even be focusing on these particular orders? Which orders are the most cost-effective to prioritize?
Wave picking helps answer these questions and solve these problems. The entire philosophy of wave picking has two central elements:
- Planning each day’s orders by prioritizing which should be fulfilled according to predetermined criteria
- Batching these orders and releasing them in “waves” that all employees work on simultaneously
We’ll get into what criteria warehouses use to batch orders and how this creates efficiency later in this post.
It’s worth mentioning that facilitating wave picking is almost impossible without an IMS (inventory management system). Wave picking is best suited for larger warehouses with lots of square footage to traverse or organizations with many SKUs.
Trying to manage, batch, prioritize and release these “waves” of orders to warehouse employees is an impossible task without some digital system. You’ll soon see why.
What Are the Advantages of Wave Picking?
Wave picking sets clear expectations for the day
If you’re easily stressed or flustered, warehouse work is probably not the career for you. Anyone who’s worked in a warehouse — especially a disorganized one — knows that the energy can get chaotic very quickly.
This tendency toward anarchy is especially prevalent when there’s no clear direction for who should fulfill what and which orders take priority.
It sounds dramatic, but this can lead to workers literally crashing carts and forklifts into each other in frantic attempts to get orders out the door.
It’s not only inefficient but dangerous. Here’s how wave picking mitigates these issues.
Wave picking surveys the entire backlog of orders and asks three simple questions:
- How many of these can I get out the door tomorrow?
- Which of these are the most important to fulfill tomorrow?
- By what criteria does it make sense to batch these orders?
This is where an IMS comes in. A robust inventory management solution like SkuVault can intelligently sort items by specific criteria and priority.
Once warehouse managers answer these questions with a substantial degree of confidence, It’s time to build out the waves themselves. These waves, which utilize Short Interval Scheduling (SIS), are the bread and butter of wave picking. (More on that in the next section.)
Nothing completely eliminates the stress of a high-energy warehouse, but having a plan goes a long way.
Wave picking reduces warehouse waste
Warehouse waste is measured in time. Minutes and seconds are the precious currency of an efficient warehousing operation.
Wave picking eliminates two disparate, but closely-related categories of waste:
Wave picking reduces motion waste
Motion waste is the unnecessary or inefficient movement required to fulfill orders. Motion waste includes traversing or blocking warehouse “lanes” to complete an order or moving machinery in an unproductive way.
Motion waste also dramatically increases the risk of injury and unwarranted traffic jams, as alluded to in the previous section.
Wave picking reduces waiting waste
“I’m not paying you to stand around and kick rocks.” It’s a phrase uttered by bosses since the dawn of time. The problem is that most warehouse workers waiting around aren’t merely lazy or incompetent. They actually have nothing to do.
In other words: it’s not a motivation issue. It’s a delegation issue.
This inefficiency in personnel utilization stems from dozens of different causes. It could be that their zone isn’t receiving any orders in a Zone Picking scenario. Or it could be because they’re waiting to process orders at the staging area.
(Many large warehouses have a place where items are picked and collected to be processed. This is often called the staging area, and having an employee assigned to this area permanently can be a significant source of waiting waste.)
Even still, they might be paralyzed by indecision as to which orders to prioritize due to unclear directions from leadership.
A well-executed wave picking plan eliminates all these problems.
Wave picking mitigates poor customer experiences
All customer experiences are downstream from your warehouse operations. Poor warehouse operations correlate to poor experiences with your brand.
Wave picking affords larger warehouses a degree of excellence absent from most other picking philosophies.
This means more orders are more likely to be on time, accurate, and fulfilled cost-effectively.
Now, before we dive into the disadvantages of wave picking, we need to take a quick detour and talk about the “secret sauce” of what makes wave picking so great — Short Interval Scheduling (SIS).
SIS refers to how employees are scheduled in sprint-like bursts to fulfill orders. This process has numerous benefits for warehouse managers and operators, specifically in maximizing employee efficiency.
What is Short Interval Scheduling (SIS) and Why Does it Work So Well?
Waiting waste is not only unproductive for your business, but it sabotages employee morale as well. If your employees are standing around waiting, they’re more likely to get out of a picking “flow state.”
Research on this psychological phenomenon demonstrates that when humans are distracted or taken out of their “flow,” it can take up to 15 minutes to get back in a productive groove.
Before we talk about the nuts and bolts of SIS, let’s dig a bit deeper into the problem that it’s trying to solve.
Namely, why do employees just stand around?
Let’s say you’ve got a large warehouse operation with lots of SKUs. Your aim is to fulfill orders as they come in — in real-time. After all, it worked when you were a smaller operation, so why not now?
Well, one employee might be assigned a massive order, another might get a small one. The larger order takes an hour to pick while the small one takes 15 minutes, making it difficult to monitor and maximize the flow of goods in the warehouse.
Once the small order is finished, should the employee move onto the following order, or help get the large order out the door? How does this impact other pickers moving around the warehouse? You can see how easily this scenario can go sideways, especially when you’re compounding this complexity with a large warehouse and more employees.
On top of that, you see literal traffic jams in your warehouse as employees are trekking from one corner of the warehouse to another to fulfill a single order. You don’t need an MBA to recognize the inefficiency in this.
To fix this problem, you implement a Zone Picking philosophy. Zone picking, much like “zone defense” in American football, is when you assign employees to specific zones in your warehouse.
Their job is to be ready to fulfill any order that falls into their “zone.” Well, what happens when no orders fall into their zone that day? Or, what happens when an order comes in that requires picking 1-2 products from their zone and 12 products from other zones?
That means this employee must wait for their coworkers to finish picking their products before fulfilling, packaging, and processing the final order. Completing the task at hand is contingent on others’ work. In the meantime, all the employee can do is stand around and watch.
Let’s go back to wave picking and how it helps solve these problems. Once the manager batches orders into a wave, that wave is released to everyone.
All employees are assigned an equal amount of orders or products to pick, often batched by zone or priority, and it’s an “all-hands-on-deck” situation until they complete the wave.
The complexity of prioritization and equal batching is one of the many reasons why doing this by hand is impossible. You need an IMS.
Once everyone picks their products, takes them to the processing area, and fully fulfills them, the next “wave” is released.
Generally speaking, waves can last anywhere between one and four hours. This translates to between two and eight waves for full-time employees on a given shift.
Everyone works together to accomplish a shared goal. It sounds so simple, yet so many warehouse managers overlook this simple concept of scheduling work in short, efficient bursts.
What Are the Disadvantages of Wave Picking?
There are always going to be trade-offs in any picking or warehouse management philosophy. As much as we’ve sung the praises of wave picking in this post, it’s not without its drawbacks.
Wave picking requires software
We’ve mentioned it several times already, but it must be reiterated. Trying to batch waves of orders by multifaceted and complex criteria is no easy task.
An efficient IMS will consider prioritization criteria across the wide swath of your orders. It can then parse out items according to zones or batches (multiples of the same SKU) and distribute these responsibilities equally across your workforce.
Trying to do it manually? That’s a fools’ errand.
It’s no surprise that we at SkuVault believe every eCommerce business sets itself up for success with a great IMS, so it’s tough to even call software a “disadvantage.”
That said, there’s no getting around the fact that wave picking requires an initial investment in a good IMS.
Wave picking is inflexible
Any time you make a concrete plan, you run the risk of being inflexible. That’s the problem with concrete — it’s not exactly malleable.
What wave picking affords warehouses in the area of productivity, costs them in the area of spontaneity. For many managers, this is a small price to pay. Just be aware that any deviation from the plan — even when a “high priority” order comes in — will derail the entire day.
Wave picking may introduce sorting errors
Remember the staging area mentioned above? In wave picking, the employee focus is on picking items primarily, not orders primarily. It’s only once employees pick all items and place them in the staging area that the orders are processed.
This is a major part of the wave workflow — everyone picks, then everyone processes. Only then is the wave complete and the next one released. Herein lies the equality of responsibility that makes wave picking such an efficient way to eliminate waiting waste.
The potential problems arise when sorting through mountains of product in the staging area. When dealing in high volumes, it’s easy for employees to put products in the wrong parcels. This is especially problematic when the waves are large or involve a wide variety of SKUs.
Of course, to err is human. Expecting any picking philosophy to be 100% accurate just isn’t realistic. That said, you’ll want to make sure that your pickers take just as much care in sorting and processing items into specific orders as they did in their picking process.
How to Optimize a Wave Picking Strategy
At this point, you may feel confident this picking philosophy is the right one for your warehouse. How can you ensure you’re maximizing your wave picking strategy for all it’s worth?
Formulate a reasonable delivery commitment
How many orders will you fulfill by “End of Business” (EOB)? Starting to design your wave picking strategy begins with this bottom line number. How many orders is it realistic to process in one workday?
Sometimes, you don’t have a choice in the matter if you’ve set a delivery precedent with your customers. Obviously, promised orders first will take priority.
Decide on a staging zone and processing workflow
Once the waves are picked, they’re sent to the staging area for sorting. You can have a full-time employee assigned to this staging area so that employees don’t have to do it all at the end. However, as mentioned above, you’re now introducing more waiting waste in the lulls between order processing.
Most likely, the most efficient way forward is to have all employees pick their waves, and then all employees process those orders in the staging area.
Determine what picking method is right for you
There are several permutations of wave picking, such as:
- Batch wave picking – employees are assigned to pick one type of item rather than an entire order. This is ideal for warehouses with several product variations.
- Zone wave picking – employees are assigned waves in certain physical locations of the warehouse. This is ideal for geographically large warehouses with a high risk of traffic jams.
- Hybrid wave picking – this is a combination of batch and zone wave picking. Employees are assigned to pick specific items in a specific location, regardless of the overall order. This is best suited for very large warehouse operations that need to parse their process down even further than the aforementioned categories.
The key is to understand your operation and decide on a strategy that works for you. Of course, if you don’t want to burden yourself with doing an expensive experiment, you can use advanced tools such as SkuVault’s HyperPicking. More on that in a bit.
Building Out Your Waves for Wave Picking
So far, we’ve talked a lot about batching orders in waves according to certain criteria. This begs the question — according to what criteria should managers batch their picking waves? That depends on your goals, but here are a few templates to start with
Batching Waves by Promised Delivery Times
If your eCommerce organization offers multiple shipping tiers, you can prioritize your daily waves according to promised delivery times. Obviously, any same-day or rush deliveries would be batched as the first waves of the day.
The following waves would be batched according to delivery times in descending order. This is the most logical and straightforward approach to wave batching.
Batching Waves by Delivery Region & Cut-off Time
Sometimes, due to delivery logistics and transportation schedules, it makes more sense to batch orders by their destination.
It’s not uncommon for deliveries to the West Coast to be on different schedules than the Northeast. Missing a certain delivery cut-off could compromise your promised delivery times. If you’re shipping all across the country (or even worldwide), you’ll want to batch according to this criteria.
Batching Waves by Product Type
All delivery times being equal, it’s beneficial to batch waves by product type. For example, if you’re a mobile phone accessory retailer, batching all orders of one particular iPhone case into a wave makes things stupid simple for pickers.
Doing this also almost completely eliminates the risk of erroneous fulfillment, as there’s no risk of the “wrong” product going into an order.
Hyper Picking: An Even Better Way Forward
At SkuVault, we know that picking is a massive part of inventory management. That’s why we’ve put countless hours into developing the most efficient picking system possible.
With SkuVault, employees can pick both digitally or with paper pick lists. The system generates pick lists according to certain pick “routes.” These routes minimize motion waste and backtracking.
Pick lists work great for wholesalers with lots of orders or companies in the early stages of their business. But for large warehouses who outgrow standard pick lists, SkuVault’s Hyper Picking system is the best way forward.
Hyper Picking is a digital form of picking similar to wave picking. However, Hyper Picking utilizes an intelligent location system and filters from wave picking sessions to create the most efficient pick route possible.
Managers can automate picking sessions by filtering the highest-priority orders. If you use physical bins, Hyper Picking even allows the option of picking based on the capacity of bins in a cart.
Filters are especially helpful during Hyper Picking because they dramatically decrease fulfillment time. Managers can assign filters to specific employees and immediately populate their pick lists instead of having to manually create them.
Prioritizing how employees pick products is both an art and a science. SkuVault exists to simplify these complex processes so business owners and warehouse managers can get out of the weeds and focus on tasks that move the needle for their business.
To learn more about how SkuVault can help automate your inventory management practices and maximize your bottom line revenue, reach out to our team today.
