Industries
Jobs per hour, the model launch, and the line that cannot absorb another variant.
A plant already posts jobs per hour. Body shop, paint, and final assembly share one takt, and a station that cannot hold it takes the line with it. The rack that feeds paint, booth time, and first-pass units that do not leave the line sit inside that same number.
A running line and a launch occupy the same floor and do not run the same way. Jobs-per-hour on the current model is not the same problem as the first weeks of the next one — same crew, different work content.
The mix shifts and the balance sheet written for the base model does not hold. Option content that was never in the original station work shows up as overtime at one job and idle at the next.
A late sequence stops the line from outside the building. The andon is inside. The part is not.
Time on the floor goes to station balance against takt, launch work content versus the running model, sequenced inbound to the line, and andon response when the stop is outside the building. What we do is the full method.
60 s
Takt many assembly lines still run to. JPH is that number expressed as jobs.
Typical high-volume line cadence; AllAboutLean on automotive assembly takt (60–90 s common).
90 days
The window a plant usually treats as the new-model launch.
Plant launch window, not first-90-day owner quality surveys.
30%+
Option content that a balance sheet written for the base model does not hold.
Option content / mix variability as a line-load problem; Fisher & Ittner on automotive option variety.
1 station
An andon stop that takes the whole line with it.
Line-stop practice on a moving assembly conveyor; Toyota Production System andon.
Final assembly posts takt. A station that cannot hold it when the mix shifts stops body, paint, and the jobs behind it.
Option content the base-model sheet never carried. Work piles up at one job and leaves the next one waiting.
Same crew, different work content, first ninety days. JPH on the current model is not the launch problem.
A late rack from a tier supplier stops the line. The andon is on the floor. The part is not.