FIFO
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FIFO (First In, First Out) ensures items are processed or consumed in the order they arrived, preventing aging and maintaining flow.
Definition
FIFO (First In, First Out) is an inventory management and material flow principle ensuring that items are consumed or processed in the same sequence they arrived. This prevents older items from sitting while newer items pass them, which causes aging, obsolescence, and inconsistent lead times. FIFO lanes are physical channels where material enters one end and exits from the other, making it impossible to break the sequence. FIFO is simpler than supermarkets (no kanban management) but requires sequential processing.
Examples
A FIFO lane between machining and heat treatment holds parts in sequence. Parts enter from machining, advance down the lane, and exit to heat treatment in the same order. The lane has a capacity limit; when full, machining cannot add more until heat treatment consumes from the other end.
Key Points
- FIFO maintains sequence and prevents cherry-picking
- FIFO lanes have capacity limits that control WIP
- Simpler than supermarkets—no kanban management required
- Used between processes when sequence must be maintained
Common Misconceptions
FIFO is just about product freshness. While FIFO does prevent aging, it also maintains flow discipline, prevents WIP accumulation, and ensures predictable lead times by keeping items moving in order.
Any queue is FIFO. True FIFO prevents sequence violation by design—physical lanes, software constraints, or procedural controls that make breaking sequence impossible, not just discouraged.
Play It
Flow Pro runs the same line two ways: items pushed through in batches of five, then one at a time. You load stations, inspect at the quality check, and pull defects out to rework. In the batch round the queue between stations grows and a defect is found long after it was made. FIFO is the discipline that keeps that queue short and in order, and the second round is what a short queue feels like.
See Also
- Supermarket - Alternative controlled inventory approach