As previously introduced, the two core picking modes in the industry are Pick-by-Order (order-based picking) and Pick-and-Distribute (product-based batch picking). They differ significantly in logic, workflow, applicable scenarios, and equipment requirements. Today, we will provide a detailed analysis of these two modes.
I. Pick-by-Order
The picker handles only one order at a time, following an optimized picking path to collect all the items required for that order from the shelves until it is complete. This method is less prone to errors and easy for beginners to adopt. Additionally, since the order is completed in one go, there is no need for secondary sorting or consolidation, saving time and space in the sorting step.
1. Main Features
- Order-oriented: Each order is processed as a single unit, with the picker collecting all required items for that specific order.
- Single-pass completion: The order is picked and packed continuously, without mixing with other orders.
- Simple operation: The workflow is straightforward, easy to understand and implement, suitable for standard process training.
- No waiting: Orders can be picked as they arrive, without waiting for batch accumulation.
2. Workflow
- Order receipt: The system receives a customer order.
- Generate picking task: The system creates a picking list for the order, specifying all required items and their locations.
- Sequential picking: The picker follows the list and path, collecting the specified quantity of each item from its storage location into an order bin or picking cart.
- Completion and verification: Once all items for the order are picked, they are sent directly to the packing and verification area for final checking before shipment.
II. Pick-and-Distribute
The picker processes multiple orders simultaneously, collecting items for these orders together, and then delivers all items along the picking path to a designated distribution area for sorting into individual orders. Compared to pick-by-order, this method significantly reduces travel distance, handles multiple orders in one trip, and increases path efficiency. It also improves the picking volume per unit time, especially suitable for scenarios with a high number of orders.
1. Main Features
- Product-oriented: Items are picked based on the SKU, gathering quantities needed for multiple orders at once.
- Secondary distribution: The core step is distribution, where batch-picked items are assigned to their respective orders.
- Efficiency-focused: By aggregating the same item demands from many orders, picker travel distance and repetitions are reduced, significantly increasing single-item picking efficiency.
- Batch processing: Orders need to be accumulated and processed together.
2. Workflow
- Order aggregation: The system accumulates multiple orders over a period for consolidation analysis.
- Generate consolidated picking list and distribution list:
- Consolidated picking list: Guides batch picking of items (e.g., Item A, total 50 units).
- Distribution list: Guides sorting in the distribution area (e.g., Order 1 needs 2 units of A, Order 2 needs 3 units of A, etc.).
- Batch picking: The picker collects large quantities of the same SKU according to the consolidated list and transports them to the distribution area.
- Sorting and distribution: In the distribution area, items are accurately placed into containers representing different orders according to the distribution list or electronic labels.
- Order consolidation and shipment: After all items are sorted, each order bin contains the full set of items, followed by verification, packing, and shipping.
III. Equipment used for the two modes
Both Pick-by-Order and Pick-and-Distribute can use automation equipment to improve efficiency and accuracy. The commonly used key equipment for each mode includes:
1. General equipment (used in both modes)
- Handheld terminals (PDA): Receive picking instructions, scan barcodes/QR codes for confirmation, enabling paperless operations and real-time data interaction.
- Picking carts/material handling equipment: Used for transporting items or order bins (e.g., AGVs, forklifts, pallet jacks).
2. Equipment for Pick-by-Order
- Order picking cart: A cart with multiple bins, one bin per order.
- Voice picking system: Communicates location and quantity instructions via headset, freeing hands and improving efficiency.
- RFID technology: Enables batch scanning, speeding up verification for large items or full-case picking.
- Electronic shelf label picking system (DPS): Each location has an electronic label showing the quantity required for the order; pickers follow label instructions to reduce errors.
3. Equipment for Pick-and-Distribute
- Automated sorting system: Highly automated equipment that uses barcode or vision recognition to distribute items into order-specific chutes or packages, suitable for ultra-large e-commerce warehouses.
- Dynamic weighing machine: Weighs packages after sorting or before packing, comparing with system expected weight for quick verification.
- Electronic shelf label picking system (DPS): Same as above, reduces picking errors.
IV. Comparison Summary
Choosing between Pick-by-Order and Pick-and-Distribute should consider order characteristics (batch size, variety, differences), warehouse equipment, and customer requirements:
If orders are small batch, high variety, and highly differentiated, with a need for quick response → choose Pick-by-Order.
If orders are large batch, low variety, and high overlap, requiring high efficiency → choose Pick-and-Distribute.
In practice, a hybrid mode can be adopted (e.g., Pick-by-Order for urgent orders, Pick-and-Distribute for regular orders), or the WMS system can dynamically adjust (e.g., automatically switch modes based on order volume), achieving a balance between efficiency and flexibility.
