FMEA is a procedure which is used within the field of operations management to identify areas of potential failure modes. The procedure has a system which classifies the potential failures according to severity (the failure modes) or by determining what effect that the failures would have on the system (the effects).

Manufacturing industries use this procedure or system quite widely and it is also being used within various sectors of the service industries. Within the world of FMEA, there are various terms used, often indtiscriminately but they have very specific meanings within this context.

Failure Modes:

Failure modes are mistakes or errors within any process. These may also be in the design of the product or the machinery or in the finished product itself. The failure modes do not have to be real; they could simply be potential failures. The key element of the failure modes is that they could potentially adversely affect the customer, so they need to be identified and then actions taken to ensure that they are eliminated, or that they do not happen!

Effects Analysis:

The effects analysis is basically looking at the effects of the mistakes or failures and what the consequences could be.

Severity:

This refers to the consequences of the failure or error. The severity looks at the ‘worst case’ scenario and attempts to use the level of severity to indicate which errors or failures will have the worst consequences.

Occurrence:

Within an FMEA it is also important to look at how often a failure occurs. For example a failure that is identified as being minor in terms of severity may occur almost every day. This will affect how seriously it is viewed, so in a sense it is a balance between the severity (which is the most important criteria) and the occurrence, since no failure that happens frequently can be tolerated.

Failure Cause:

The failure cause, is to some extent self explanatory, but it looks at what may cause the failure in terms of its root cause. Is it due to design? Is it caused by working practices? Is there any quality issue that has not been addressed?

Application of FMEA

Within FMEA, various failures are identified and then given a priority, according to their potential severity. So a failure which could be designated as a low risk, because the failing will ultimately have only a minor effect, will be dealt with only after very severe failures have been dealt with.

The FMEA also provides a written ‘history’ of the decisions taken, the risk assessment, the actions that were then taken to ensure that the failures were removed. This enables continuous improvement to be undertaken and because records clearly show decisions taken etc, then it is not possible for people to claim that they ‘didn’t know’ about the potential failures etc.

FMEA and Design

FMEA can also be used within the design process, to ensure that it can design out any failure modes. FMEA can clearly indicate which of the risks has the highest risk and so these can be addressed prior to the design being finalised. Typical issues that may arise relate to safety, reliability, performance and quality. So addressing these before a workcell or machine is designed, there is a real opportunity to maximise performance.

FMEA Updates

An FMEA has to be updated, as machinery may change, or even working practices and processes change. This is important, because any changes to the environment or processes used could significantly alter the accuracy of the accuracy of the FMEA. But when they are kept up to date and carried out in a manner that is methodical and thorough, they are an extremely useful tool used to drive forward improved performance.

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