Definition
The ability to allow products or processes to move in the shortest possible delivery cycle, in a high quality and in the most economical manner.
In detail
Flow is the ability of a product or service to move smoothly through a process with the shortest lead time, high quality, and most economical manner. It emphasizes eliminating stagnation, waiting, and backtracking, allowing value to flow continuously. In the lean system, flow is a core principle, complementing pull and perfection. Unlike pull systems, flow focuses on continuity within the process, while pull focuses on demand signals between upstream and downstream. The output is typically a continuous flow production layout or process design that reduces WIP inventory and delivery time.
Example in practice
An electronics assembly factory found that products were transferred in batches between multiple processes, leading to long waiting times. Through value stream mapping, they rearranged equipment, adopted U-shaped cells, and implemented one-piece flow. Employees operated to takt time, and downstream processes pulled from upstream, reducing transportation and waiting, significantly shortening delivery lead time.