Definition
The minimum amount of material required to ensure normal flow of operations is the enabling condition of a single stream.
In detail
Standard Work-in-Process (SWIP) is the minimum amount of WIP required to ensure smooth flow of work. It is an enabler for one-piece flow. It addresses the problem of operators being interrupted due to waiting for materials, ensuring that each station has enough WIP for operators to work continuously, thereby achieving smooth flow. Unlike inventory, SWIP is a precisely calculated minimum necessary amount, not excess buffer. It typically becomes a key parameter in standard work documents, guiding on-site material configuration and work balancing.
Example in practice
On an assembly line, an operator had to wait for the next part to arrive after completing a process, causing work interruptions. By calculating the SWIP at each station, the minimum number of parts to be placed before each station was determined, ensuring operators can work continuously without waiting. After implementation, work flow became smoother, waiting waste was reduced, laying the foundation for one-piece flow.