2026-04-02
When a changeover swallows the hour count
On many lines the official changeover window is forty minutes and the actual window is whatever happens between the last good piece of SKU A and the first good piece of SKU B that packing will accept. That gap often includes hunting for the next die, waiting for a sign-off, and running a first-off that quality has not yet seen. If the shift log only has a “C/O” box, all of that collapse into one planned number and the day looks fine on paper.
Mark three clocks, not one: last good A, first piece of B off the machine, and first piece of B that clears the quality check used for the official count. The middle clock is useful for the setter. The last clock is the one that belongs on the throughput chart, because units the plant cannot ship are not units.
We often find the mechanical swap is inside the planned window and the wait for gauges or labels sits outside it. Crews already know this. The written record does not. A quality trend walk that never looks at first-off pieces will miss the same delay from the other side of the aisle.
If a plant wants a local record of these three clocks, a desktop utility that never leaves the room can hold them. That is record-keeping, not a production control system. The floor still runs on the setter’s sequence and the supervisor’s call.