Failure Mode Effects Analysis

Failure Mode Effects Analysis (FMEA)

Typical FMEA worksheetFailure Mode Effects Analysis (FMEA) or to give it its correct title Failure Mode Effects & Criticality Analysis (FMECA) is a logical technique used to identify and eliminate possible causes of failure. The technique requires a sequential, disciplined approach,  to assess systems, products or processes in order to establish the modes of failure and the effects of failure on the system, product or process. This is to ensure that all possible failure modes have been fully identified and ranked in order of their importance. The FMECA discipline requires the documentation (see worksheet opposite) of any evaluation with regard to the failure mode, effect and criticality. The analysis work can be applied at any stage; design, manufacture, test, installation or use, but is best performed at the early (development or design) stage. In a simple system the study may be performed on the total system or product but with more complex systems it may be necessary to break the product down into various sub-systems or sub-assemblies.

The technique is often seen as part of an organisation's; Lean, Value Stream Analysis, Root Cause Analysis programme.

Reasons for FMECA

With ever increasing demands to ensure that QUALITY is achieved RIGHT FIRST TIME then still greater pressures are placed on the engineer or process developer. This is to ensure that the process or design performs consistently, reliably and safely throughout the life of the product or process, thus providing a quality product or service that completely meets the demands of the customer. Designers and developers are only human, they can make mistakes and have off days just like everyone else. FMECA ensures that any inadequacies in the product or service are quickly identified, preventing the possibility of releasing sub-standard products or providing a sub-standard service. Product testing will of course help identify any design deficiencies, there are however, possible limitations with this approach:

 

bulletIf the product fails the trial then the modified and hopefully improved design will need to be retested - this can lead to inefficient use of resource.
bulletProcess improvement
bulletTests and trials can usually only be performed on a limited number of products, consequently all the possible variations in specification and build standard cannot always be evaluated. Using small samples may also not be sufficiently accurate to predict field failure rates, particularly when attempting to identify causes of potentially low field failure rates (½ or 1%). These missed potential failures may result in the need for product recall or the issuing of advisory notices, (particularly in the case of safety critical failures). This can be not only expensive but also damaging for both the company and product's credibility and reputation.
bulletRegulatory Reasons
bulletContinuous Improvement
bulletPreventive (not corrective) approach
bulletTeam Building
bulletRequired by Procedures e.g. specifically dossier for submission when CE marking

Other reasons may include, meeting the requirements of:

bulletISO TS 16949 - Quality management systems - Particular requirements for the application of ISO 9001:2000 for automotive production and relevant service part organisations
bulletAS9100 - Quality Management System Requirements for Design and/or Manufacture of Aerospace Products or AS9110 - Quality Management System Requirements for Maintenance Organisations
bulletBS EN 60812 Analysis techniques for system reliability. Procedure for failure mode and effects analysis (FMEA)
bulletISO 14971 The application of Risk Management to Medical devices
bulletBS EN 31010 The standard associated with Risk Management techniques

Stage

Process Function

Possible Failure Mode

Effects of Failure on System

Cause

O

S

D

R

Action to
eliminate

Receiving

Initial check for identification, damage & paperwork. Segregate & locate items from untested and test.

Inadvertent use of untested items

Loss traceability

Possible use of defective materials

Human
error

2

10

5

100

Separate incoming goods .

Labelling

Identify product with part number

Operator error, documentation not clear, note identifying area small

Loss of traceability

Human
Error

2

10

5

100

Automatic label generator printing correct details

Review Cert of Conformity

Confirm product tested and within spec.

Material has deteriorated. Wrong material sent

 

Human
Error

1

10

1

10

Product sent for analysis

 

So FMECA provides the potential for:

bulletReducing the likelihood of Customer Complaints
bulletReducing the likelihood of campaign changes
bulletReducing maintenance and warranty costs
bulletReducing the possibility of safety failures
bulletReducing the possibility of extended life or reliability failures
bulletReducing the likelihood of product liability claims

Typical FMECA Process

For further information

bullet Training courses
bullet Software
bulletFMEA Support
bullet FMEA Free Software

If you would like to know more about FMEA please contact Sales at:

Telephone:    +44 -0 1483 453511Fax:    +44 -0 1483 453512 Postal address:   Quality Management & Training Limited PO Box 172, Guildford, Surrey, GU2 7FN United Kingdom Electronic mail:
Technical Support: help@qmt.co.uk
General Information: sales@qmt.co.uk
Customer Support: tutor@qmt.co.uk

 

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© Quality Management & Training Limited    Friday, 16 April 2004

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