FMEA or Failure Mode and Effects Analysis
Design FMEA
1 - PURPOSE
This document defines how to apply the method of FMEA (Failure Mode and Effects Analysis) to a product.
The purpose of the Design FMEA is to analyze the potential modes of failure of a product, caused by its design and definition.
This technique of preventative analysis makes it possible to do the following:
{ Look for product malfunctions caused by its design and definition,
{ Evaluate their potential effects on the customer,
{ Identify the possible causes connected with the design and definition of the product,
{ Look for appropriate preventative actions.
2 - SCOPE
This method of analysis applies to the design and development of any new product during the quality planning phase.
3 - DEFINITIONS
DATE OF ORIGINAL OF THE STUDY:
This is the date the study specifications were written.
REQUESTER:
Person who, as part of his or her functions, has the power to request that an FMEA be carried out, in agreement with the "decider".
DECIDER:
Person who, as part of his or her functions, has the power to employ the human and financial means necessary to carry out the FMEA and to implement the plan of action resulting from it. The requester and the decider can be the same person.
FUNCTION:
Service to be provided by each element of the product. Example : To ensure air-tightness.
FAILURE MODE:
Malfunction of an element of the product leading to a partial or total failure to satisfy its function. It is judged in relation to each function. There are one or more potential failure modes for each function, e.g., cracked (split), non-airtight, oxidized.
EFFECTS:
These are the possible consequences of the failure mode on the products performance during use, as perceived by the customer, e.g., slow decrease in pressure, irregular wear of the cover.
CAUSES:
These are the causes, relating to the choice and definition of a product element, which can provoke a failure mode. These causes can involve:
{ The material (nature and quantity),
{ Shape,
{ Position,
{ Links with adjacent elements,
{ Identification.
There can be several possible causes for a failure mode. Likewise, one cause can generate several failure modes. These causes can be:
{ Independent: A cause generates a failure mode for itself. Example: Poorly defined shape.
{ Combined: Several causes must arise together for a failure mode to be generated. Example: Poorly defined shape and position.
DETECTIONS:
These are all the different means (human and/or material) which exist during the design period (before production of the product) which could prevent a non-conform product from reaching the customer, e.g., verification by calculating in terms of finished elements, trials, tests.
CLASSIFICATION:
This is left to the initiative of the product lines and serves to identify failure modes, which could affect a special or main characteristic of the finished product. This identification can be in the form of an asterisk.
SEVERITY (S):
This is the severity of the consequences of the potential effects as felt by the customer. Severity is scored from 1 to 10 using a pre-determined scale.
A failure mode can have consequences of varying degrees of severity. The score it is given corresponds to the most serious consequences, which could reasonably be observed.
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OCCURRENCE (O):
This is the probability that the potential cause of failure will occur and that it will bring about the failure mode being considered. This is irrespective of the severity of the consequences. Occurrence is scored from 1 to 10 using a pre-determined scale.
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