Cycle

A cycle is the time from the start of a process until the operator (or machine) is ready to start the next time through the process.

An alternative definition of cycle says it is the time from the start of one part until the start of the next part.

The problem with the second definition of cycle is that it fails to address the wait time that is inherent in linked processes, such as on an assembly line. One station may finish early, and then have to wait to start the next cycle. With the second definition, all stations on a moving assembly line would have the same cycle time.

For machines, a cycle can be misleading. It may only take a small amount of time to process one part to completion. This cycle does not, however, take the setup time into account. There can be a substantial overhead which often drives large batch sizes.

The actual measurement of a cycle—cycle time—is used to balance a line to takt time and make sure it is capable of efficiently producing to customer demand.