What is carton flow racking, and how does it speed up order picking?

Detailed Answer

Carton flow racking works on the same gravity principle as pallet flow, but at the case and carton level rather than full pallets. Each shelf lane is fitted with rollers or skate wheels set at a slight downward pitch. Cases are loaded at the back (high end) and roll forward to the pick face at the front (low end). When a picker pulls a carton from the front, the next one advances into position automatically.

This design speeds up picking in three ways.

• First, it reduces travel time. In a standard shelving or selective rack setup, pickers walk up and down long aisles to reach each SKU. Carton flow racking concentrates a high number of SKUs into a compact pick face, which means more picks per linear foot of aisle. A picker working a carton flow section can fill orders with significantly fewer steps than the same picker working a traditional shelf layout.
• Second, it separates picking from replenishment. Pickers work the front of the rack while warehouse associates or forklifts restock from the rear aisle. In a conventional shelving setup, replenishment blocks the pick aisle and forces pickers to wait or reroute. Carton flow eliminates that conflict entirely. Pick faces stay full, and pickers never lose time waiting for a restock.
• Third, it enforces FIFO rotation at the case level. The oldest carton is always at the front of the lane, which matters for food, beverage, pharmaceutical, and any product with lot codes or expiration dates. There is no reliance on manual discipline or WMS overrides to pull the right case.

Carton flow racking is most commonly deployed inside pick modules, which are multi-level rack-supported structures that combine bulk pallet storage above with case-pick flow lanes below. Full pallets are broken down on the upper level and loaded into the flow lanes, where pickers on the lower level pull cases directly to conveyor lines or packing stations. This vertical integration dramatically reduces the floor space needed for a picking operation and shortens the path from reserve stock to a shipped order.

Even outside of a full pick module, carton flow works well as a standalone solution for operations that pick high volumes of mixed-SKU cases. E-commerce fulfillment centers, grocery distribution, parts distribution, and retail replenishment operations all see measurable gains from replacing static shelving with carton flow in their highest-velocity pick zones.

The main considerations when specifying carton flow are lane width (sized to the carton dimensions for each SKU), lane depth (typically three to six cartons deep depending on replenishment frequency), weight capacity per lane, and the roller or wheel type best suited to your packaging. Smooth-bottomed cases roll well on skate wheels, while irregular or lightweight packaging may need full-width rollers for reliable feeding.

Warehouse Cubed’s layout and design team evaluates your order profile, SKU velocity, and carton dimensions to determine where carton flow fits into your operation and how to integrate it with conveyors, pick modules, or existing shelving. If your pickers are spending more time walking than picking, a free consultation is a good place to start.