Knowledge Post: What are the common order-picking models used in e‑commerce warehouses, and how can they be implemented?

Release date:

2025-01-24

Author:

Jinhua Logistics

618, Double 11, Double 12—throughout the year, there are countless e‑commerce promotional events. How can you effectively boost picking efficiency in your e‑commerce warehouse to ensure swift order fulfillment and delivery?

01 Understanding Types of E-commerce Picking Models

With the rapid growth of e‑commerce, the role of logistics and warehousing in supporting its development has become increasingly prominent. Warehousing operations constitute a fundamental set of activities that underpin e‑commerce production, management, and competitive advantage. Sorting accounts for the majority of both time and cost in warehouse operations; therefore, optimizing e‑commerce warehousing and sorting processes is of critical importance.

By analyzing the characteristics of contemporary e‑commerce warehousing, sorting strategies can be optimized. Warehouse operators conduct data analysis and categorization of orders and develop tailored sorting plans, which effectively eliminate redundant tasks, enhance overall efficiency, and ensure orderly operations. Sorting strategies are pivotal to sorting performance and typically encompass zone allocation, order splitting, batch processing, and classification. The interplay among these four factors gives rise to a variety of sorting approaches.

Specifically, what sorting methods are used in e-commerce warehouses?

Introduction to Sorting Method Types

E‑commerce warehouses primarily employ three picking methods: single-item picking, also known as “pick‑and‑place” picking; batch picking; and pick‑and‑pack.

1. Order-based picking—picking by the “pick-to-light” method. When picking items, goods are sorted into different picking containers according to the order and then sent to the packing area for packaging.

2. Consolidated picking—batch picking. During the picking process, items are sorted by category and sent directly to the packing area, where they are then consolidated and packed according to each order.

3. Pick and broadcast simultaneously—sort and sort as you go. It combines the features of both pick‑to‑cart and put‑to‑cart operations. For example, multiple picking bins are loaded onto a single cart, with one bin per order; orders can be placed sequentially. Operators use handheld PDAs to perform intelligent picking within the warehouse based on order details, followed by a second verification before packing and placing the items on the conveyor belt, thus completing the shipping process.

(1) Broadcast Picking

Sowing‑type sorting resembles the sowing process: multiple orders—each representing a customer’s product requirements—are consolidated into a single batch. First, the quantity of each item is tallied separately. Then, pickers, following the order sequence, collect all items of the same type in one go and place them in sorting containers. Finally, the sorted items are distributed to each customer by product category, a method that mimics sowing; hence, the term “item‑by‑item aggregation and sowing” is more appropriate.

Features: 1) Process multiple orders or several customers at once. 2) The operations are complex and highly challenging.

Applicable: Suitable for warehouse environments with high order volumes that require high-speed processing.

Advantages: In warehouses with very high order volumes, picking efficiency can be significantly improved by reducing the distance traveled and the amount of handling required during the picking process, thereby increasing the number of items picked per unit of time.

Shortcomings: Centralized picking reduces picking time but introduces additional sorting and consolidation steps in the downstream verification and order‑assembly stages, thereby increasing the processing time of these operations compared to single‑order picking.

In practice:

Sowing-type sorting systems that also employ electronic display tags are commonly used.

The warehouse initiates picking waves, with each wave comprising multiple customer orders. Picking labels are printed for that wave, one label per item, containing information such as the customer order number and the designated picking location. Pickers process all items in a single wave, retrieving them according to the labels and placing them in a picking cart. Once a wave is complete, the cart is moved to the sorting area, where each electronic‑tagged bin corresponds to a specific order (a particular customer). Operators first scan the barcode to enter the details of the items to be sorted into the system; the electronic tag associated with the required bin lights up, displaying the quantity needed at that location. Picking personnel or automated equipment then move between the bins assigned to each customer, dispensing the exact quantities indicated. After sorting is finished, shipping documents, invoices, and waybills are printed and placed in the corresponding customer‑specific bins. Finally, the items are double-checked against the documentation, packed, weighed, and consolidated for shipment.

The process is as follows:

1) Receive customer sales orders. The WMS receives customer sales orders from the ERP system and generates picking instructions within the WMS.

2) Initiate the wave. Fulfillment operations, also known as “wave management,” filter fulfillment notices based on various criteria—such as order source, courier company, presence of an invoice, and VIP status—to segment orders into waves, initiate internal warehouse processes, and generate picking lists for in‑warehouse order picking. At the same time, the system automatically assesses whether replenishment is required from storage locations to picking stations by comparing the wave‑specific demand quantities with the available stock at each location. If replenishment is needed, the system automatically generates a replenishment order and sends a replenishment instruction to the picker’s RF device.

3) Restocking. Replenishment staff restock picking locations for items that are low in inventory; the system supports multiple replenishment triggers and strategies, including pre‑picking replenishment of an entire wave’s demand to the picking locations, as well as incremental replenishment during the picking process. It also enables customization of replenishment strategies and algorithms to meet individual customer requirements.

4) Label picking. Each picker can process multiple orders simultaneously during the picking process—say, 50 or even 100 orders—depending primarily on their capacity to handle that volume.

5) Split broadcasting. After picking the items, place them on the PTL sorting location. Each order corresponds to a single sorting location. When placing the items in the location, use an RF device to scan the picking label and the consolidation location barcode, link the two, and then transmit the association back to the WMS system via RF.

6) Print the shipping label, courier waybill, and invoice, then pick and place the items at the corresponding consolidation location for the order. Supports RF‑based scanning of picking documents, associating document barcodes with consolidation location information.

7) Recheck, pack, and weigh. At the consolidation location, conduct a total count of all full‑case and piece‑goods items, and use an RF/scanning platform to scan the goods, documentation, and consolidation‑location information. Once the verification is complete, select appropriately sized cartons, pack the items from the consolidation location into the boxes, and then weigh them.

a) Scan-based re‑verification: To enhance picking accuracy and reduce the substantial follow‑up effort required to correct errors, items must undergo a second verification. A scanning platform is employed to improve verification efficiency: each item’s picking label, shipping manifest, courier waybill, and invoice are scanned individually. Upon completion of the scan‑based re‑verification, the carton is moved into the packing area.

b) Packing: Remove the shipping label, seal the box with plastic tape, and affix the label to the outside of the box.

c) Weighing: Place the box on the electronic scale, scan the courier waybill barcode, and record the weight. The weight is automatically entered into the system and displayed on the screen. The weigher then manually transcribes the weight shown on the screen onto the courier waybill. Finally, place the box in the pending‑shipment area.

d) When the courier company picks up the shipment, hand over the delivery box to them.

e) Upon completion of the handover, record the handover in the system and transmit the information to the ERP system to notify the customer of the logistics operation’s progress.

This label‑based picking combined with PTL picking is well suited to logistics centers that handle high annual order values, require substantial capital investment, and demand a high level of accuracy.

(2) Pick-and-Place Picking

The pick‑by‑putting method resembles the act of picking fruit. Pickers fulfill each order—i.e., each customer—by moving between storage locations to retrieve the required items and place them into the appropriate containers or vehicles, much like picking fruit from a tree.

Features: 1) Each person handles only one order or one customer at a time; 2) Simple and easy to use.

Applicable: A warehouse that stores a wide variety of products, with relatively low order volumes.

Advantages: 1) Easy to learn: For new employees, the pick‑by‑put‑away method is relatively straightforward, reducing training and onboarding time. 2) One‑walk picking allows all items for a single order to be picked in a single pass, eliminating the sorting and consolidation steps required in batch‑picking.

Shortcomings: When the number of SKUs is large, it significantly impacts picking routes and efficiency, leading to longer order‑picking and outbound processing times. Moreover, when multiple workers simultaneously pick from the same zone for different batch orders, congestion in the aisles can occur. Additionally, the larger the picking area, the more challenging material handling becomes.

In practice:

Electronic display tags are typically used for pick‑to‑light picking. Each product variety (storage location) is generally assigned a dedicated electronic tag. The control computer system, based on item locations and order data, issues shipping instructions and illuminates the corresponding electronic display tag on the shelf. Operators then use these tags to pick the correct quantities promptly and accurately.

The process is as follows:

1) Restocking: The storage area delivers goods to the piece-picking area, placing each item on the shelf one by one.

2) Along-the-line picking: The tote bins move along the sorting conveyor line, and sorters retrieve items from the shelves and place them into the bins.

3) Re-inspection and packing: Goods already packed into turnover boxes are checked for correct variety and quantity, and sometimes they must be repacked into new boxes.

4) Consolidation and Freight Forwarding: Deliver the already inspected and packed cartons to the shipping area and await dispatch.

(3) Picking and sorting simultaneously

Pick-and-sort is a picking method designed for multi‑item orders. The process involves first consolidating a specified number of orders, then using RF devices and picking carts to sort and allocate items directly into the designated storage locations for each order as picking progresses.

Operating procedure:

1) The computer system consolidates orders according to warehouse‑zone‑optimization rules, ensuring that all picking orders for a single wave are concentrated within a relatively small operational area. This way, our picking operations are confined to that specific zone.

2) Distribute the consolidated orders from this wave to each storage location on the picking cart, with each location corresponding to a single order. This step is referred to as the “order broadcasting” operation.

3) Receive picking instructions via the RF device and proceed to the work area with the picking cart. The RF display shows the total quantity for consolidated picking and presents, in graphical or list format, the quantity to be picked for each order. Follow the RF prompts to pick directly from the designated locations, adhering to the specified quantities.

This operational model is well-suited for e‑commerce products in the apparel, cosmetics, and 3C sectors. It is particularly appropriate for logistics centers with small warehouse footprints, an average order size of 2–3 line items, high‑value SKUs, and daily shipment volumes of no more than 10,000 orders.

02 Measures to Improve Picking Efficiency

Here are some efficient methods for order picking in e-commerce warehouses:

1. Rational warehouse layout: Arrange the warehouse according to product categories, storage requirements, and other factors to facilitate quick location of items and reduce search time.

2. Clearly label storage locations: Assign a clear location identifier to each storage bin, such as labels or shelf numbers, to facilitate quick retrieval of product locations.

3. Make efficient use of shelving: Based on the product’s size, weight, and other characteristics, select appropriate shelf types and dimensions to maximize space utilization while ensuring that the shelves meet the required load‑bearing capacity.

4. Establish an effective inventory management system: By using inventory management systems such as ERP and WMS, you can achieve real-time monitoring of product inventory, order processing, shipment management, and more, thereby improving operational efficiency.

5. Regularly organize inventory: Regularly organize the warehouse, dispose of expired, damaged, and slow-moving items, and maintain a clean and orderly storage environment.

6. Arrange manpower appropriately: Based on order volume, product type, and other factors, appropriately schedule the number of pickers and shift assignments to enhance operational efficiency.

7. Establish a standardized picking process: Establish standardized picking procedures, such as first-in-first-out and order‑based picking, to ensure orderly execution of picking operations.

8. Use picking tools: Using picking tools such as electronic picking carts and label printers can help quickly locate items and improve picking accuracy.

9. Conducting concurrent operations: When order volumes are high, cross‑docking can be implemented, allowing multiple pickers to perform picking simultaneously in the same area, thereby improving operational efficiency.

10. Conduct regular employee training: Conduct regular training for employees to enhance their professional skills and service awareness, ensuring smooth order-picking operations.

The above are several methods for improving picking efficiency in e‑commerce warehouses, which can be selected and adapted based on the specific circumstances.

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