Welcome to the course, Failure Mode and Effects Analysis. Often reliability is achieved by performing extensive testing in the late stages of product development. Failure Mode and Effects Analysis (FMEA) is used to identify potential failure modes early in the development cycle. FMEA not only identifies potential failure modes, it is used to determine their effect on the product. FMEA is also used to identify actions to mitigate the potential failures. Using FMEA allows companies to design out failures and produce more reliable, high quality products.

Many engineers and developers use a less formal approach to think about potential failures and ways to prevent them. FMEA provides a formal, more disciplined, technique.

Initially the information may be subjective. It may be estimates based upon the information available. However, as actual data becomes available the FMEA analysis should be updated to reflect this progress.

While not all problems can be anticipated, a genuine effort is made to identify problems in advance and look for solutions. The emphasis on teams working together will help ensure success.

The first formal application of FMEA didn not occur until the mid 1960's when FMEA was used in the space industry. Widespread use began in the 1970's by automobile manufacturers. FMEA is currently being used by many industries.

Product recalls can be very expensive. Avoiding product failure and the ensuing bad publicity and/or lawsuits makes this tool very worthwhile. It is sometimes difficult to put a price tag on a problem that never happened, but avoiding one major problem will usually more than pay for the time and effort put into completing an FMEA.

Let's start with an example of a Design FMEA. Here is a cross-sectional view of a product called the Fizz-Keeper. It is used on two liter bottles of soda, soda pop, or pop (depending upon which part of the USA you are in). When the bottle is opened the carbon dioxide begins to effervesce - it "fizzes". In order to keep leftover pop from going flat, this product is screwed onto the bottle and the bottle is repressurized.

Having the right team members is critical to an accurate and complete FMEA. Representatives of many different points of view should be part of the team or be available as needed to be called in for discussion.

The main difference between FMEA and typical "post-mortem" analysis done on a program is the FMEA is FUNCTION-DRIVEN. The first step is to identify all of the functions of a part, component or system. This is a very important first step and must not be short-circuited.

Reducing a function to a two word combination will express it in the simplest form.

In this example, the potential Failure Mode is that it leaks air from the chamber into the atmosphere.

Failure modes do not have to be catastrophic. When a component does not accomplish what was intended, that is considered a failure. There can be multiple effects resulting from a given failure mode.

Here is an example of the severity criteria that is often used in the auto industry. A rating of 1 is a very low severity of failure. A rating of 10 is the worst severity of failure that can occur. Attempt to make the scale linear between 1 and 10.

List every conceivable failure cause assignable to each potential failure mode. Causes should be described so that remedial efforts can be aimed at those causes which are pertinent.

If there is historical data available, it should be used either directly or as a guideline for making decisions about frequency of occurrence and detection. Objective data should be used whenever possible. If no data is available then make a subjective evaluation initially and change it to objective data as it is gathered.

Increasing inspection may serve as a temporary measure to lower the RPN, but it is not as desirable as lowering the occurrence or severity.

A Process FMEA is similar to a Design FMEA in that it assesses the severity, occurrence and detection of potential failures. A Process FMEA differs from a Design FMEA because it does not rely upon design changes to reduce the Risk Priority Number. It does take into account manufacturing and assembly processes to assure that the resultant product meets customer requirements. Let's look at an example from the fast food industry for our Process FMEA.

Notice the header information is not identical to the Design FMEA. This is only an example and should be customized for your project.

Maintaining the sense of urgency is sometimes difficult to do. Often a problem has been present for so long that it is taken for granted that it will always be present. Use the FMEA evaluation to drive the committment to improve.

Anytime processes are changed or improved the FMEA should be updated. Even when the change is proposed but still in the evaluation stage, it would be proper to examine how it would affect the RPN.