Monitoring infrequent failures of high-volume production processes

We present a case study in monitoring a high-volume production process with a high yield. Testing the products is difficult and is only possible in a destructive way with a defect/no-defect result. We review several attribute charting procedures for high-yield processes. It turns out that monitoring the number of conforming items between the occurrence of non-conforming items is appropriate. We discuss several implementation aspects of CCCr charts in our case study. The implementation is based on a new formula for the standard deviation of the number of inspected items before a signal.