Design Controls prevention and Detection
Just a note while on the road in New York about prevention and detection controls. Some confusion exists about these two very distinct types of controls.
Prevention controls include things that help you do it right the first time without having to physically test. These include FEA, Modeling technology, Product DNA, and Standards that can be followed. Note that FEA in a iterative design process as opposed to using a the design process. These Type 1 controls affect the Occurrence number and are not to be evaluated for the Detection ranking.
Detection controls or type 2 controls are used to detect design weakness and potential errors. Tests and formal protocols, physical representations of parts, past test results etc… each is rated independantly of each other for each cause and failure mode. the lowest value is used for the detection ranking to be included in the FMEA. More on Process FMEA in my next post