Cycle time vs takt time

Cycle time and takt time sound interchangeable and are constantly mixed up, but they answer two different questions. Cycle time is how fast you actually make a part. Takt time is how fast you need to, to meet demand. Get the difference straight and a lot of scheduling, staffing and OEE confusion clears up at once.

Takt time: the pace of demand

Takt time is the rhythm customer demand sets. It's the available production time divided by the number of units customers want in that time: the beat the line must hit to keep up, no faster and no slower.

If you have 420 productive minutes in a shift and need 840 units, takt time is 30 seconds: you must finish one good unit every 30 seconds to ship the order on time. Takt is a target, set by the market, not the machine. Work out yours with the takt time calculator.

Cycle time: the pace of the line

Cycle time is how often a finished part actually comes off the line: the real, observed interval between completions. It's a measured fact about your process, not a goal.

Two flavours are worth separating:

• Ideal (or design) cycle time: the fastest the equipment can produce one unit under perfect conditions. This is the benchmark OEE measures speed against.
• Actual cycle time: what you really get once minor stops, slow running and small jams are included. It's always slower than ideal.

How they relate to OEE

Healthy lines keep cycle time < takt time. If your fastest possible cycle is slower than takt, no amount of efficiency saves you: the line physically can't meet demand and you need another shift, another line, or a faster process. If cycle is faster than takt but you still miss the order, the gap is losses, and that's exactly what OEE measures.

Ideal cycle time is the heart of OEE's performance factor: performance is the ratio of the output you'd get at ideal cycle time to what you actually got.

So an accurate ideal cycle time isn't paperwork; it's the yardstick your whole performance number is built on. Set it too slow ("sandbagging") and a mediocre line looks great; set it honestly and OEE tells you the truth. The full method is in how to calculate OEE.

A worked example

• Takt time: 420 min ÷ 840 units = 30 s/unit needed.
• Ideal cycle time: the machine can do one every 20 s, comfortably under takt, so the line is capable on paper.
• Actual cycle time: with stops and slow running you average 33 s/unit, now slower than takt, so you'll miss the order.

Nothing is wrong with the machine; it's the 13 seconds of losses per unit between ideal and actual. That's where OEE points you, and where improving OEE recovers the order without buying a faster machine.