A Failure Mode and effect analysis, or FMEA, is a quality-planning tool used to identify and eliminate potential product or process failures or defects.
By using an FMEA, the practitioner can systematically identify, analyze, prioritize and document potential failure modes, their consequences on a system, product or process and prevent future failures from occurring.
The aplications of FMEAs are nearly limitless. Early applications were largely oriented towards flight safety in the aerospace industry. Safety FMEAs have since spread into manufacturing, design and development, administrative, accounting and finance process as an attempt to eliminate errors and reduce failures and customer complaints. Wether the FMEA is being accomplished on a complex system, product or process, the earlier it is used in the life cycle of a product or process, the greater the potential for positive resoults.
When and How Use the Failure Mode & Effect Analysis?
Prior to beinning an FMEA, the following should be addressed:
- An appropiate, cross-functional team should be commissioned and a team leader selected. All team members must know who the FMEA "owner" is.
- Next, the system, product or process must be thoroughly defined. For a process, a process follow diagram or process map, defined elsewhere in this guide, best accomplishes this. For a system or product, this can be accomplished using schematics, blue prints, engineering or manufacturing diagrams and drawings, or prototypes if available.
- The FMEA´s boundaries must be clearly defined to include deadlines, product limitations, budget(s), usuable resources, report format(s), final report dissemination or any other limitations.
- The size or scope of the problem must be considered. If the task is too large for one FMEA, it Might be advantageous to break the problem into smaller pieces and attend to each piece separately.
The basic steps for conducting a FMEA are as follows:
- Study the system, product or process to be analyzed.
- Brainstorm, over the multiple brainstorming session, the possible range of failure modes.
- List the potential consequences of each failure mode.
- Assign severity (SEV) scores for each failure mode.
- Identify the cause(s) of each failure mode.
- Assign occurence (OCC) scores for each cause.
- Identify current controls to detect the failure modes.
- Assign an escaped detection (DET) Score for each cause and control.
- Calculate the Risk Priority Number (RPN) for each line in the FMEA
- Prioritize the failure modes and causes based oin the RPN
- Determine the action(s) to be taken.
- Re-calculate the RPNs based on the action plans.
Ideally, the steps of an FMEA should be accomplished in order and each steps should be complete before progressing to the next step. However, this does not preclude the team from backtracking when they deem it necessary due to errors, incomplete steps, or incomplete information.
