Track 1 Session 9
8:00 to 9:00 a.m. Friday April 9, 2010
Identify and Fix Reliability Problems Missed by FMEA and Validation Testing Before Shipping
Despite widespread adoption of FMEA and best practice validation testing, OEMs suffer from growing warranty costs. In this presentation, a stepper motor case is used to illustrate the following points: 1) Most economic impact from performance and reliability failures can be classified as infant mortality. 2) Failures are easily predicted from a device’s energetic behavior; in small population samples at the end of the production process, whether failures are few or many parts per million, hard or soft. The key is to characterize functions of a device. The methodology exploits the fact that simple rules govern the flow of energy and these are consistent across all energy domains: electrical, rotational, translational, fluid, chemical, etc. There are only seven types of functions driving behavior, and fewer that need to be characterized. Functional testing can be done hierarchically, at t0 to tn, allowing high risk functions to be found rapidly through a progressive search. This extremely successful methodology extends to failures classified as premature wear-out, because further energetic interaction with environments causes decay in function performance.
Key Words: FMEA, FMECA, Risk, Function, Validation, Diagnosis, Reliability Management
David J. Hartshorne
The New Science of Fixing Things Ltd.
UK