The different order picking methods
- Single-order picking: This method involves involves picking all items for a single order before moving on to the next one.
- Batch picking: Operators prepare multiple orders simultaneously. Picking tasks are organized according to the similarity between the SKUs that need to be picked in order to fulfill different orders. The items are collected together (in batches), which reduces operators’ movements, then routed to a dedicated area where they are sorted and assigned to the relevant orders to be shipped.
- Zone picking: In this method, the warehouse is divided into zones and picking operators are responsible for collecting items within their assigned zone. This zone-based approach groups together items that are often ordered together or are similar in terms of size, weight, or other characteristics. Once all the items in the order have been collected in the respective zone, they are then routed to a consolidation area, where they are grouped together and checked to make sure the order is complete.
- Wave picking: This method involves picking several orders simultaneously. The orders are then grouped together according to carrier type, shipping lead times, product types and dimensions, or other criteria. These groups of orders form “waves.”
- Waveless picking (or waveless fulfillment): Here, instead of grouping orders in waves and running the pick at specific points in time, pick tasks are allocated dynamically as orders come in over the course of the day. This method is especially well-suited to e-commerce operations, where promised lead times are typically short.
Order picking: Special cases
- Cross-docking: Products are transferred straight from the incoming goods area to the shipping area. The items may be repacked or grouped, but the overall aim of this method is to keep handling and storage times to a minimum.
- Drop shipping: In this case, the order is forwarded directly to the supplier, which handles order picking and shipping. The seller does not physically handle the product at all.
- Kitting: This method involves grouping different items, parts, or components together to form a kit—a single unit that is ready to be shipped.
- Co-packing: Here, individual products are grouped, assembled, or packed together in a single dispatch pack according to customer requirements or current promotions.
- Store picking: In physical retail outlets, operators pick orders from stock in the sales area and storeroom.
Automated and semi-automated picking
Orders can be picked manually by logistics operators, or using automated or semi-automated systems such as:
- Voice picking systems: Voice technology guides operators throughout the order picking process in the warehouse.
- Conveyor systems: Conveyors transport the products to the picking operators.
- Sorting machines: These machines collect and transport products or cartons and deposit them in the correct sorting area according to their destination.
- Pick to light systems: Lights guide picking operators to the item locations.
- Horizontal and vertical carousels: These storage systems rotate around a horizontal or vertical axis, automatically bringing the items to the picking operators. Carousels are capable of storing large quantities of items in a compact space, thereby freeing up room for other activities.
- Automated storage and retrieval systems (AS/RS): These machines automate the item storage and retrieval process.
- Picking robots: Robots are programmed to collect items from various locations in the warehouse.
Under goods-to-man systems, the items are automatically routed to the picking operators. With man-to-goods systems, meanwhile, the operators move through the warehouse to collect the relevant items.
Several of these methods can be used in combination in order to limit operators’ movements, boost efficiency, optimize storage space, reduce the risk of picking errors, and more. But whatever method is chosen, the warehouse management system (WMS) orchestrates the order picking process— can even determine the most appropriate picking strategy. So before you choose a WMS, make sure it can accommodate your target processes!