Order picking is a core function in any distribution operation. There are a variety of warehouse order picking methods and strategies used to help save time, increase productivity, optimize accuracy, and cut costs. Zone picking is a strategy used by many large DC’s with a variety of SKU’s.
In this post we will define zone picking, discuss the pros and cons, and describe one particular zone picking strategy that many companies have used with Lucas to improve productivity when picking orders that contain both slow- and fast-moving items.
Definition: Zone Picking
Zone picking can be thought of as the warehouse picking version of an assembly line, in which parts of an order are picked in different zones by different workers. The zones in question can be sections within a pick module, or larger pick areas that may be defined by product type (bulk, flammable, grocery), racking type, environmental features (freezer, cooler), SKU velocity, and/or picking processes: for example, a static shelving area, a high velocity each pick module, or a case-pick zone, etc.
In large DCs with diverse products and large numbers of SKUs, orders containing products from different pick areas may be broken up and picked by zone, and the items picked in the various zones are then consolidated prior to shipping. For example, B2B orders may be consolidated in an outbound staging area: cases from one area can be placed on the same pallet with totes picked in an each pick area. Put walls are another popular method for order assembly, especially in ecommerce fulfillment.
Pros and Cons of Picking by Zone
Con: Separate parts of the order need to be combined after picking
When order lines are picked in multiple zones, the products will need to be consolidated post-pick, adding a step to the outbound process.
Con: Balancing work across zones may be challenging
The volume of work by zone is likely to fluctuate throughout a work day, leading to times when some zones are very busy and others are waiting for more work. Therefore, it may be necessary for managers to re-allocate or shift workers from one zone to another. This also requires that workers are trained to work in different zones.
Pro: Improve slotting by velocity
Zone picking is extremely useful for warehouses that have a large number of SKU’s, with diverse product characteristics. Zoning products based on SKU velocity allows DCs to design different picking processes that are tailored to optimize the process for the particular velocity of products in different zones.
Pro: Increase picker productivity by optimizing processes
Dividing products by velocity or other characteristics allows DCs to optimize their picking processes across all item types rather than employing one pick process for all products. For example, by placing high volume items in case flow rack where a pick and pass process is used, versus lower volume items in static shelving or racks where a pick-to-cart process is used.
Pro: Reduce congestion
Zone based picking will typically reduce the number of workers per zone, reducing congestion.
Pro: Cut travel time
Zone based picking reduces the area covered by each picker, so travel time is significantly reduced. Since travel may account for 30-70 percent of travel time in picking, this represents a significant additional productivity boost.
Zone Picking Example: Two-Stage Picking
The animation below describes how slow- and fast-moving items may be picked in different zones in a coordinated two-stage picking process. This is one example of how zone based picking increases productivity, despite adding a consolidation step for the slow moving items.