Process failure mode effects analysis (PFMEA) has long been part of advanced quality planning (AQP) or advanced product quality planning (APQP). Previous approaches were subject to drawbacks and limitations such as (1) the need to quantify the probability of a failure mode's occurrence and (2) the status of the risk priority number (RPN) as the product of three ordinal numbers (Severity, Occurrence, and Detection).
The newest approach, as described by the AIAG/VDA (2019) FMEA handbook, does away with these limitations while offering a logical and structured FMEA process that helps ensure that all potential failure modes are identified and then disabled or at least suppressed. The tables for assessment of Severity, Occurrence, and Detection are easy to understand, and Occurrence and Detection ratings are based not on quantitative estimates but rather on the nature of the process' prevention and detection controls, which are in turn synergistic with the control plan that is required by IATF 16949 (and recommended very highly for ISO 9001 users). The Occurrence and Detection tables also make it clear that engineering controls, or machine-based controls, are superior to administrative controls that rely on worker vigilance. This principle is consistent with Shigeo Shingo's Zero Quality Control: Source Inspection and the Poka-Yoke System.
The new approach also replaces the RPN with an Action Priority (Low, Medium, or High) that depends on the Severity, Occurrence, and Detection ratings with Occurrence receiving more weight than Detection. This reinforces the principle that it is better to prevent the defect or nonconformance (e.g. with poka-yoke or error-proofing) than to detect it after the fact, even if the detection controls (e.g. self-check systems) intercept the defect before it can reach the next process.
Attendees will gain an overview of the newest and most advanced approach to PFMEA, and illustrative manufacturing examples along with an occupational health and safety (OH&S) example. The goal is to make PFMEA more user-friendly and also more effective in terms of ensuring that processes deliver their intended outputs. The webinar will also show how a control plan can be appended to a PFMEA to create a dynamic control plan.
William A. Levinson, P.E., FASQ, CQE is the principal of Levinson Productivity Systems, P.C. He is also the author of several books on quality, productivity, and management, of which the most recent is The Expanded and Annotated My Life and Work: Henry Ford's Universal Code for World-Class Success.