What Is the Lapse Rate?

Failure rate refers to the product that has not expired until a certain time, and after that moment, the probability of failure in unit time. Generally referred to as , it is also a function of time t, so it is also referred to as (t), which is called the failure rate function, sometimes also called the failure rate function or risk function.

Failure rate priority

RPN does not play a significant role in selecting actions to prevent failure modes. They are to a greater extent the threshold for evaluating these actions.

After grading severity, frequency of occurrence, and ease of discovery, simply multiply these three values to get the RPN:

RPN = S x O x D

This must be done for the entire process and / or design. Once completed, the determination of the maximum focus area will be easy. In terms of corrective action, the failure mode with the highest RPN should receive the highest priority. This means that failure modes with the highest severity values do not necessarily need to be addressed first. The first things that should be dealt with are those failures that are relatively low in severity, but occur more often and are less easily detected,

After these values have been assigned, the action recommendations with goals, responsibilities, and implementation dates are recorded. These actions can include specific inspections, tests or quality procedures, redesigns (such as selecting new components), adding more redundancy, and limiting environmental stress or scope of work. Once these actions have been implemented in the design / process, new RPNs should be checked to identify improvements. To facilitate visualization, these tests are often presented as graphics. Whenever a design or process changes, the FMEA should be updated.

The logical and important points are:

Try to eliminate failure modes (some failures are easier to prevent than others). Minimize the severity of failures. Reduce the frequency of failure modes.

Failure timing

The FMEA should be updated whenever:

· The beginning of each cycle (new product / process)

· Changes to operating conditions

· Make design changes

Established new laws or regulations

· Consumer feedback indicates a problem

FMEA Use of Failure Rate FMEA

Establish system requirements that minimize the possibility of failure.

Establish system design and test methods to ensure that corresponding failures are eliminated.

Evaluate consumer needs to ensure that they do not cause potential failure.

Identify certain design characteristics that contributed to the failure and minimize or eliminate the impact.

Track and manage potential risks in your design. This helps to avoid the same failures in future projects.

Ensure that any failures that may occur will not harm consumers or seriously affect the system.

Failure rate advantage

Improve product / process quality, reliability and safety

Improve company image and competitiveness

Increase user satisfaction

Reduce the time and cost of system development work

Gather information to reduce future failures and gain engineering design knowledge

Reduce the possibility of order problems

Early detection, identification and elimination of potential failure modes

Prevention of key issues

Minimize subsequent changes and their associated costs

Promote teamwork and exchange of views between different functional departments

Limitation of failure rate

Since FMEA actually relies on committee members who are responsible for investigating product failure issues, their experience with past failure issues also constrains FMEA. If a failure mode cannot be determined, external assistance is needed from consultants who understand the failure issues of many different types of products. Therefore, FMEA is part of a larger-scale quality control system; of which, documentation is essential for implementation. In the field of engineering technical qualification (forensic engineering) and failure analysis (or failure analysis), there have been general articles and detailed publications in 2013. The application of FMEA in the evaluation of product integrity has been a general requirement for many specific national and international standards in 2013.

If used as a top-down tool, FMEA may only find the major failure modes in the system. Fault tree analysis (FTA) is more suitable for top-down analysis. As a "bottom-up" tool, FMEA can enhance or supplement FTA, discovering and identifying much more causes and failure modes of top-level symptoms. FMEA cannot detect complex failure modes that involve multiple failure issues within the same subsystem, or report that specific failure modes are appropriate for the expected failure interval of a higher-level subsystem or system.

In addition, multiplying the severity, frequency of occurrence, and difficulty level of discovery may cause a level reversal phenomenon, that is, a less severe failure mode will get an RPN higher than a more severe failure mode. The reason this happens is that these classifications belong to ordinal scale numbers, and for them, multiplication is not an efficient method of operation. Hierarchical rank only indicates that one rank is better or worse than another rank, but it does not say to what extent. For example, a rank of "2" does not mean that it is twice as bad as a rank of "1", or a rank of "8" does not mean that it is twice as bad as a rank of "4" . However, the above multiplications treat them as such. For further discussion, see Level of measurement.