Cycle Time

Cycle Time is the total time a production station spends completing one part; it covers loading, processing, unloading, and intra-station transitions. Its unit is typically minutes/unit or seconds/unit. Cycle time is often confused with takt time and throughput but is distinct: takt is the target rhythm imposed by the customer, cycle time is the station's actual processing time, and throughput is the system's hourly output. On a line of several stations, system throughput is constrained by the station with the longest cycle time (the bottleneck): throughput = 1 / max(cycle time). This is the mathematical foundation of Goldratt's Theory of Constraints argument. Cycle time splits into two parts: value-adding time (truly transforming the product) and non-value-adding time (loading, gauging, motion). The lean target is to drive the non-value-adding share to zero. The fundamental parameter matrix of job-shop scheduling, assembly line balancing, and flow-shop scheduling problems is the cycle-time matrix (m machines × n parts). SMB measurement practice: stopwatch time study, video analysis, or automated MES tracking. Variability (cycle-time variance) is as critical to system performance as the mean — Hopp and Spearman (1996) 'Factory Physics' stress this point: when variance is high, throughput at the same mean cycle time drops (queueing effect). References: Taylor 'The Principles of Scientific Management' (1911); Hopp and Spearman (1996); ISO 22400-2.