Takt Time

Takt time is set by demand, not by the machine. That is the distinction people miss. Cycle time is what your equipment actually achieves; takt time is what the customer's volume requires. Quoting a line means proving your cycle time comes in under takt with margin to spare, and the size of that margin is a commercial decision as much as an engineering one.

The margin exists because takt assumes perfect operation and nothing operates perfectly. Tool changes, part starvation, minor stoppages and rework all consume time that takt does not account for. Integrators typically design to 85 to 92 percent of takt so the line still meets its number on a bad day. Design exactly to takt and the line misses its target every week.

When a bid package states a JPH figure rather than a takt time, they are the same requirement in different units: takt in seconds equals 3600 divided by JPH. A 55 JPH line has a 65.5 second takt. Converting between them is the first thing to do on any line enquiry, because the rest of the quote hangs off it.

Takt, cycle and JPH, converted

• Takt from JPH: 3600 / JPH. 55 JPH gives a 65.5 second takt.
• JPH from takt: 3600 / takt seconds. A 48 second takt gives 75 JPH.
• Takt from demand: available seconds per shift / units required per shift.
• Design cycle: usually 85 to 92 percent of takt, to absorb downtime.
• Bottleneck station: the one station whose cycle exceeds the rest; it sets the real line rate regardless of takt.