Order picking is the productive operation in a warehouse. Any warehouse design exercise that doesn’t include a rigorous approach to the processes and equipment layout for order picking is suspect.
Picking is where products are selected and retrieved from stock to fulfil customer orders. In most operations it remains manual and time-consuming, and it demands accuracy, speed and attention to detail in equal measure.
It matters because it drives customer satisfaction, warehouse cost, and business performance. Get the process right and you cut labour costs, lift productivity, and hold onto customers who would otherwise go elsewhere.
When we pick an order, we are essentially manufacturing the thing the client pays us for. Obvious, perhaps, but worth stating plainly. If picking takes too long, costs rise and profitability falls. If we get it wrong, the client doesn’t receive what they’re paying for.
Split Case and Full Case Picking
Setting aside full pallet picking, there are two main types of order picking operation, and most warehouses run some combination of both.
Full case picking means whole cartons are picked and assembled into orders.
Split case picking means cartons are opened and some of their contents picked and packed for dispatch. In some operations the items are unpacked and placed into tubs or bins before presentation at the pick-face, which is most common in goods-to-person operations.
The cost difference between the two is substantial, and it’s worth being clear about why.
In full case picking, the operator takes a whole carton from a pallet and places it on another pallet or a conveyor. One movement, and the client is charged for every unit in that carton.
In split case picking, the operator opens the carton, counts out the required units, and repacks them. Several movements, more opportunities for error, and the client is charged for only part of the carton’s contents.
Split case picking therefore attracts considerably more cost than full case. That’s where your design effort should go.
The Three Levers of Split Case Productivity
Split case picking design should concentrate on three things: reducing operator travel, improving accuracy, and increasing picking speed. Nearly every worthwhile improvement fits under one of them.
Reducing travel comes from pick-face design, specialised equipment such as carton live storage, picking zones, and process design. Where you locate each SKU (stock keeping unit) in the pick-face, known as slotting, matters just as much as the equipment you buy.
Improving accuracy comes from pick-face design, slotting, and systems such as radio frequency data terminals, pick-to-light and pick-to-voice. A properly designed picking document will do more for accuracy than most managers expect.
Increasing speed comes from all of the above, plus a deliberate effort to strip out wasted time: the seconds lost finding a SKU, confirming the pick, and waiting for stock to arrive at the face. Those seconds are small individually and enormous in aggregate.
Split case picking is complex, and the service level a company delivers depends on it running error-free and on time. Design it well, support it with the processes around it, and the profitability of the whole warehouse improves.
Picking Methods, and What Each One Buys You
There are several picking methods. Rather than list them neutrally, it’s more useful to sort them by which of the three levers they pull.
Discrete picking means one picker completes one full order before starting the next. It pulls no lever particularly well, because travel per order is at its highest. It survives because it’s simple to run and easy to supervise, and for low order volumes that’s often enough.
Batch picking consolidates the same SKU across many orders, so the picker visits each location once and picks the total quantity. It’s the strongest travel-reduction method available, and it’s the right default for high-volume operations. The catch is that it requires a downstream sortation step to break the batch back into individual orders, so you’re moving work rather than removing it.
Cluster picking has the operator pick into several separate containers at once, one per order. It reduces travel like batch picking but needs no sortation afterwards, because the orders were never combined. Where your order profiles suit it, it’s usually the better of the two.
Zone picking divides the warehouse into areas, with each picker responsible for their own. It cuts travel and reduces congestion in the aisles, but orders spanning several zones then have to be consolidated before packing.
Wave picking is often listed alongside these, and it shouldn’t be. A wave is a decision about when work is released, not how it’s picked. You can run waves with zone picking, batch picking or any of the others. Waves are worth using to smooth labour planning and align picking with carrier departures, but treat them as a scheduling tool rather than a picking method.
Tools Worth the Investment
The equipment that supports picking maps onto the same three levers.
- Automated storage and retrieval systems (AS/RS) attack travel directly by bringing goods to the operator instead of the other way round. The largest gain, and the largest capital cost.
- Conveyor and sortation systems move and sort items so pickers don’t have to, which is what makes batch picking viable at scale.
- Barcode scanners and printers are the baseline for accuracy, and there’s no good reason to run without them.
- Voice and pick-to-light systems improve both accuracy and speed by removing the need to read and interpret a document mid-pick.
- Mobile computers and tablets give operators real-time order and inventory information, which cuts the waiting time that quietly erodes velocity.
- Picking carts and bins are what make cluster picking work, and they cost a fraction of everything above.
A warehouse management system (WMS) sits underneath all of it, managing inventory, orders and picking tasks. Without one, most of the methods above can’t be run properly at all.
Where to Start
If your picking operation is under strain, resist the urge to buy equipment first. Look at slotting and pick-face design before anything else, because they’re the cheapest levers available and they determine how much benefit any subsequent investment will deliver. A poorly slotted pick-face will waste the money you spend automating it.
If you’d like an objective look at your picking processes, or at the layout they run in, our team of warehouse consultants can help.
