Inspection cadence: what to look for at 1K, 10K, 50K, and 100K hits

A die at 48K hits is running clean. The day-shift inspector logs "heat-check normal, flash land showing wear, dimensions in spec" and signs off. The die runs another shift. Night-shift operator notices a hairline crack on the back corner of the impression and writes "checked, no change" on the log without measuring it. The die runs another shift. Mid-morning the next day, a fingertip-sized chunk of the corner leaves the impression on a hit and lodges in the next forging. The press eats a punch holder. The line is down for nine hours.

The crack was 1.8 mm at the night-shift log entry and 3.1 mm by the time it left. The inspection cadence was the cadence. The checklist was wrong, and the log was a signature instead of a measurement.