Failure Mode Effects Analysis

Failure Mode Effects Analysis (FMEA)

Typical FMEA worksheet Failure 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:

	If 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.
	Process improvement
	Tests 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.
	Regulatory Reasons
	Continuous Improvement
	Preventive (not corrective) approach
	Team Building
	Required by Procedures e.g. specifically dossier for submission when CE marking

Other reasons may include, meeting the requirements of:

	ISO TS 16949 - Quality management systems - Particular requirements for the application of ISO 9001:2000 for automotive production and relevant service part organisations
	AS9100 - Quality Management System Requirements for Design and/or Manufacture of Aerospace Products or AS9110 - Quality Management System Requirements for Maintenance Organisations
	BS EN 60812 Analysis techniques for system reliability. Procedure for failure mode and effects analysis (FMEA)
	ISO 14971 The application of Risk Management to Medical devices
	BS 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:

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

Typical FMECA Process

For further information

	Training courses
	Software
	FMEA Support
	FMEA Free Software

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