The buffer that looks like a machine problem

Maintenance tickets accumulate on the loudest machine. That is human. The observer’s job on a throughput study is to stay with the flow of pieces, not with the noise. If the press stops with a green ready light and an operator walking toward a stack of empty totes, the hours still look like downtime on a naive log. They are waiting on material handling.

Count the pieces in the inbound buffer at a fixed interval, even a crude high/medium/low mark on a card. When the inbound mark is low and the machine is stopped, do not file it as a mechanical stop. When the outbound chute is buried and the machine is stopped, do not file it as a quality stop unless a hold was actually called.

Plants with shared forklifts see this pattern on every other Tuesday, when shipping also needs the same driver. The local record of stops will show a cluster in late morning. That cluster will never appear in a mean-time-between-failure report because nothing failed.

This is why we still do line walks with a watch and a card. Charts drawn from a single auto-collected “running” bit will sort the week by the wrong noun. The noun that matters is the one the operator uses while pointing at a tote.

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