This presentation is an actual case study and will walk through a situation where Statistical Process Control (SPC) was used, after-the-fact, to assess a supplier’s problem with a critical heat-seal process. While SPC did not identify the root cause, an analysis of the historical data from this long-running process brought to light, to both the customer and the supplier, inappropriate acceptance criteria and unrecognized output variability. The study shows the value of SPC when applied to processes with output that can only be measured with destructive testing.