Gravity is free, and unforgiving
A flow rack exists to enforce first-in-first-out without anyone policing it. Load at the back, pick at the front, and the newest item physically cannot be picked first. That is the whole idea, and it works only when slope, lane width and carton condition are matched to each other.
Almost every failure of this design is a slope problem wearing a different costume. Cartons stalling halfway is too shallow. Cartons arriving hard enough to scatter contents is too steep. One lane jamming while others run is usually a carton condition problem — scuffed or soft bases on one supplier's packaging — that no amount of slope adjustment fixes for the whole rack.
- Set slope during commissioning, not from a drawing. Build in adjustability.
- One lane per SKU in the pick face. Building too few lanes is the error that never gets corrected.
- Size lane depth to the replenishment interval. Too shallow means hourly restocking; too deep and it becomes a storage rack that defeats rotation.
- Side guides are mandatory for mixed carton sizes. Without them, narrow boxes turn and jam.
- Keep the pick face in the operator's comfortable reach band. Every pick that requires a bend is a future complaint.
Replenishment access
Plan rear-aisle access before installation. A rack pushed against a wall turns every restock into a front-of-house operation, which is exactly the condition under which FIFO stops being followed.
