Monitoring supplier quality at PPM levels

Motorola has traditionally monitored supplier quality levels using the lot accept rate. This measure, total lots accepted at incoming QA divided by the total lots received, was an adequate measure of supplier quality for many years. With the Motorola Six Sigma goal in place, supplier quality levels approached 100 percent and lot accept rate as a monitoring and rating metric lost its relevance. Suppliers with 99 to 100 percent lot accept rates began to feel that they had solved all their problems while line complaints continued to be received from Motorola manufacturing sites. Lot accept rate had lost its value as a metric for monitoring supplier quality. Line p.p.m. was chosen as a new metric for supplier quality. The authors discuss the need for the line p.p.m. metric, how the program was successfully implemented into five Motorola sites within the one year pilot project, some of the stumbling blocks encountered along the way, and the type of data that is currently being reported