Fmea

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  • Topic: Failure mode and effects analysis, Reliability engineering, Failure
  • Pages : 13 (3649 words )
  • Download(s) : 129
  • Published : February 24, 2013
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A failure modes and effects analysis (FMEA) is an inductive failure analysis used in product development, systems engineering, reliability engineering and operations management for analysis of failure modes within a system. It helps a team to identify potential failure modes based on past experience with similar products or processes or based on common failure mechanism logic, enabling the team to design those failures out of the system with the minimum of effort and resource expenditure, thereby reducing development time and costs. It serves as a form of design review to erase weakness out of the design or process. It is widely used in development and manufacturing industries in various phases of the product life cycle. Effects analysis refers to studying the consequences of those failures on different system levels. -------------------------------------------------

Basic terms[1]

FMEA cycle.
Failure
The loss of an intended function of a device under stated conditions. Failure mode
The manner or way by which a failure is observed in terms of failure of the part function under investigation; it may generally describe the way the failure occurs. It shall at least clearly describe a (end) failure state of the item/function under consideration as result of the failure mechanism (cause of the failure mode). For example; a fractured axle or an open electrical contact can be a failure mode. Failure Cause and/or Mechanism

Defects in requirements, design, process, quality control, handling or part application, which are the underlying cause or sequence of causes that initiate a process (mechanism) that leads to a failure mode over a certain time. A failure mode may have more causes. For example; fatigue or corrosion of a beam or contact is a failure mechanism and not a failure mode. The related failure mode (state) under analysis could be a "full fracture of structural beam" or for example "a open electrical contact". The initial Cause might have been "Improper application of corrosion protection layer (paint)" and /or "(abnormal) vibration input from another failed system". Failure effect

Immediate consequences of a failure on operation, function or functionality, or status of some item Indenture levels
An identifier for item complexity. Complexity increases as levels are closer to one. Local effect
The failure effect as it applies to the item under analysis. Next higher level effect
The failure effect as it applies at the next higher indenture level. End effect
The failure effect at the highest indenture level or total system. Severity
The consequences of a failure mode. Severity considers the worst potential consequence of a failure, determined by the degree of injury, property damage, system damage and/or time lost to repair the failure.

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History
Procedures for conducting FMECA were described in US Armed Forces Military Procedures document MIL-P-1629[2] (1949; revised in 1980 as MIL-STD-1629A).[3] By the early 1960s, contractors for the U.S. National Aeronautics and Space Administration (NASA) were using variations of FMECA or FMEA under a variety of names.[4][5] NASA programs using FMEA variants includedApollo, Viking, Voyager, Magellan, Galileo, and Skylab.[6][7][8] The civil aviation industry was an early adopter of FMEA, with the Society for Automotive Engineers publishing ARP926 in 1967.[9] During the 1970s, use of FMEA and related techniques spread to other industries. In 1971 NASA prepared a report for the U.S. Geological Survey recommending the use of FMEA in assessment of offshore petroleum exploration.[10] FMEA as application for HACCP on the Apollo Space Program moved into the food industry in general.[11] In the late 1970s the Ford Motor Companyintroduced FMEA to the automotive industry for safety and regulatory consideration after the Pinto affair. They applied the same approach to processes (PFMEA) to consider potential process induced failures...
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