FMEA model

What is FMEA for?

FMEA is short for failure mode and effects analysis. It helps to determine and prioritize causes and, as such, is mostly used to systematically map potential product or process failures before they actually cause any problems.

Determining scores within the FMEA model

A team searches for potential failure factors, defects and consequences of failures within each process step. Scores are then given to the gravity of the consequence, the frequency of occurrence of the defect and how reasonably possible it is to detect the cause of the defect before the consequence occurs. These scores are then multiplied by each other in order to determine a total score: the Risk Priority Number (RPN). This RPN shows the priority of the factors that need to be worked on in order to reduce the risk. The FMEA model can be used in different phases as well, in order to create and arrange relations.

Requirements for a successful FMEA analysis

Making a FMEA analysis is done with a team. To do it correctly, this team needs to prepare well. The following instruments can help provide input and improve the preparation: a process diagram, the cause and effect matrix, the process’ history and the process’ technical procedures.

The goal

Results from a FMEA analysis differ based on the purpose of the analysis and the phase in which it is applied. Outcomes can be things such as:

– An arranged list of CTQ’s (critical to quality) and y’s (output)

– An arranged list of X’s (input)

– A list of actions to prevent causes or ways of failure

– A history of taken actions and future activities

Initiating a FMEA analysis before failures occur

The FMEA is meant to enable action before any failures occur, not afterwards. Representatives from each of the involved departments are required to properly draw up the analysis. Sometimes, experts will be required to make a good estimation when it comes to certain topics in this regard. The FMEA should be a living document which is adjusted by the team whenever an action, or total number of actions, are taken. This enables the team to set new priorities. In this phase of the improvement project, the FMEA is an instrument to inventory and categorize the causes of variation in the Y (output).

FMEA in summary

The FMEA is a living document and priority list for the yet to be taken measures to improve a process. After taking action, or a collection of actions, the other team will redefine the chance of detection, the frequency and the gravity again. Subsequently, the RPN is recalculated and the list is rearranged. The cause for which actions were taken will then end up lower on the priority list, causing another cause to top it and become the next priority.