FMEA (AMDEC in French), failure modes, effects and criticality analysis, is a preventive reliability method. A working group reviews, step by step, what can go wrong in a product or a process, with what causes and what consequences, then decides on the actions that reduce risks before they occur. IEC 60812 describes the technique.
For each failure mode, the severity of its effect, the frequency of occurrence of its cause and the ability to detect it before delivery are rated, often on scales of 1 to 10. The product of these three scores gives a criticality index that prioritises actions; some recent standards, notably in automotive, prefer an action priority that gives more weight to severity.
A distinction is made between design FMEA, which covers failures of the part in service, and process FMEA, which covers manufacturing. Example in machining: failure mode “diameter out of tolerance”, cause “tool wear”, detection “in-process check every twenty parts”. The action decided may be a preventive tool change or a gauge at the machine.
In subcontracting, it is requested mainly for safety parts or high-stakes parts (automotive, aerospace, medical). The buyer supplies its design version, with the key characteristics; the workshop prepares the process version and derives a control plan from it. For a prototype or a simple small batch, it is rarely required: preparing it takes hours of engineering. It links with the first article, traceability and ISO 9001.
In a quote request
Specify whether a process FMEA is required, before the series is launched, in what format or under which standard, and whether you are supplying your design FMEA or the list of critical characteristics. Engineering time must appear in the quote; see the guide from prototype to series.