Cycle time

Cycle time is the interval between the start and the end of producing one part on a machine or station. In machining it usually runs from cycle start to program end, including cuts, tool changes and rapid moves. It is the basis for machine-hour quoting and for plant capacity.

How it works

A cycle has cutting time (the tool removing material) and non-cutting time (tool changes, approaches, part changes). Cutting time depends on speed, feed and depth of cut; non-cutting time depends on the program and the fixturing. To compare, separate the ideal cycle (the best stable cycle) from the measured actual cycle; the gap feeds the performance factor of OEE.

Practical example

A flange takes 4 min 10 s with the original program. Combining two operations on the same tool and trimming rapid approaches brings the cycle to 3 min 25 s. On a batch of 600 parts, that frees 7.5 machine hours for another order.

Common mistakes

• Quoting with the CAM simulator time without adding part loading and inspection.
• Not tracking the actual cycle and finding out at month end that the part loses money.
• Confusing cycle time with takt time, which is the pace the customer demands.