Picking is where most of the activity in the warehouse happens. There are nearly as many picking strategies as there are companies, and warehouse productivity is all over the map as a result. Here are the basic picking systems that companies have come to rely on most.
Individual Order Picking
The most common form of picking is single order picking. In this case, a picker is given one order at a time, and they travel through the warehouse to find each item on the list before returning for their next order. Ideally, the sequence in which orders are given to pickers and the routes that each picker follows in order to pick the line items are optimized, but often this is not the case. A Warehouse Management System can address these problems and increase warehouse productivity, but at the end of the day, the worker is making a full trip through the warehouse in order to fill a single order.
With batch picking, a worker is picking for several orders at the same time. A common setup is one where the worker pushes a cart with several totes on it, and each tote is dedicated to its own order. When the same part is included as a line item in more than one order, the worker picks the total quantity needed for all of the orders and then places the correct amount in each of the totes.
A robust WMS is required in order to manage the inherent complexity of the situation. It needs to direct the worker to the correct location, prompt the worker to pick the right quantity of the part and then direct them to place the correct amounts in each of the totes. This process is often guided by batch picking lights (Pick to Light) that indicate which tote should be filled at a given point in time. Batch picking is often used with AS/RS equipment like carousels and VLMs too. Your WMS needs to be able to communicate with these types of equipment in order to manage the whole process. Batch picking can result in a large boost to warehouse productivity since a single picker can now fill multiple orders at once.
Zone picking is another way to improve warehouse productivity by assigning pickers to work within a subset of the warehouse floor. One example might be to have a large parts zone that consist of shelving and a small parts area that uses carousels or VLMs. One worker picks the order in the large parts zone and then passes the tote for the order off to the worker who is in the small parts zone. You can even have each zone picked simultaneously and have the separate components brought to a consolidation area where they will be married up.
Advanced Systems Picking
Complex warehouses may use combinations of all of these approaches in order to maximize productivity. Totes for individual orders may travel from zone to zone where they are delivered into batch picking stations in which a worker is picking from carousels or VLMs. The batch picking stations use Pick to Light systems in order to direct the correct quantity to each tote. While this is happening, the bulk components of orders may be picked by workers on forklifts who are working on one order at a time or perhaps batch picking as well. All of the individual components are brought together in consolidation. You can even have scenarios where the appropriate shipping box is selected before the order is released, that box moves from zone to zone, and the line items for the order are picked into it. This effectively eliminates the need for a separate packing process.
Today, companies often combine these methods across their warehouse to optimize picking. There is no one-size-fits-all method, especially when it comes to handling large or sensitive items. The key is to find a system that suits your warehouse and your productivity goals while simplifying the process and reducing errors.