Carton flow racking is a warehouse storage system that uses slightly sloped roller or wheel tracks to move cartons from a rear loading aisle to a front picking aisle. It supports first-in, first-out inventory flow, which is important for products with dates, changing demand, or frequent restocking. The system reduces walking time for pickers because products are presented at the front face of the rack.
It also separates stocking and picking work, which can improve safety and reduce congestion.
Key Facts
- Carton flow uses gravity: cartons move down sloped tracks from the loading side to the picking side.
- Typical lane slope is about 2% to 5%, depending on carton weight, roller type, and desired speed.
- FIFO means first in, first out, so the earliest loaded carton is the first one picked.
- Available pick faces = number of lanes across the rack × number of vertical levels.
- Lane capacity = lane depth ÷ carton depth, using consistent units.
- Restock frequency = daily demand ÷ cartons stored per lane, if one lane is dedicated to one SKU.
Vocabulary
- Carton flow racking
- A storage rack system with sloped roller or wheel tracks that move cartons by gravity from a loading side to a picking side.
- FIFO
- First-in, first-out is an inventory rule where the oldest stock is picked before newer stock.
- Pick face
- The front position of a storage lane where a worker removes cartons or items for orders.
- Lane
- A single sloped track path in a carton flow rack that holds one line of cartons from back to front.
- Replenishment
- The process of adding new cartons to the loading side of the rack so the picking side stays stocked.
Common Mistakes to Avoid
- Using too steep a slope, which is wrong because cartons can travel too fast, impact the front stop, and become damaged or unsafe to pick.
- Mixing different carton sizes in one lane, which is wrong because smaller or irregular cartons can jam, tip, or fail to move smoothly on the rollers.
- Ignoring FIFO loading direction, which is wrong because loading from the picking side can trap older stock behind newer stock and create inventory aging problems.
- Calculating capacity from rack width only, which is wrong because usable capacity also depends on lane depth, carton depth, number of levels, and required clearances.
Practice Questions
- 1 A carton flow lane is 3.0 m deep and each carton is 0.50 m deep. How many cartons fit in one lane if no extra clearance is included?
- 2 A rack has 6 lanes across and 4 vertical levels. Each lane holds 5 cartons. What is the total carton capacity of the rack?
- 3 A warehouse handles snack cartons with expiration dates and high daily picking volume. Explain why carton flow racking may be better than static shelving for this product.