Trips that look acceptable individually can hide a directional process shift.

Locate the issue

Control limits are monitoring aids from a stable process, not product acceptance limits.

Build the comparison. Plot one defined measure from comparable routes and loads in time order; mark device and process changes.

Four control fields

  • Measure and unit
  • Reference period
  • Signal review
  • Process change

Let a signal trigger process review; product condition needs product measurement and authorised disposition.