What Is A failure Mode And Effects Analysis? Failure Mode And Effects Analysis In A Nutshell

A failure mode and effects analysis (FMEA) is a structured approach to identifying design failures in a product or process. Developed in the 1950s, the failure mode and effects analysis is one of the earliest methodologies of its kind. It enables organizations to anticipate a range of potential failures during the design stage.

Component	Description
Overview	Failure Mode and Effects Analysis (FMEA) is a systematic and proactive approach to identify potential failure modes, their causes, and the effects or consequences of those failures in a product, process, or system. It helps prioritize and mitigate risks to improve reliability and safety.
Key Elements	– Failure Modes: Identifying possible ways in which a product, process, or system could fail.
	– Causes: Determining the root causes or factors that contribute to each failure mode.
	– Effects: Evaluating the consequences or impact of each failure mode on the overall operation or objectives.
How It Works	FMEA involves a step-by-step process: First, identifying all potential failure modes, then determining their causes and effects. Each failure mode is assigned a risk priority number (RPN) based on criteria such as severity, occurrence, and detection. This helps prioritize which failure modes require mitigation efforts. Finally, corrective actions are planned and implemented to reduce risks and improve reliability.
Applications	– Manufacturing: Used to assess and enhance the reliability of manufacturing processes and product quality.
	– Engineering: Applied in product design and development to identify and mitigate potential failure modes.
	– Healthcare: Utilized in healthcare settings to minimize risks associated with medical procedures and equipment.
Benefits	– Risk Reduction: FMEA helps identify and prioritize potential failure modes, allowing organizations to focus on high-risk areas.
	– Improved Reliability: By addressing weaknesses in design or processes, FMEA enhances the reliability and performance of products and systems.
Drawbacks	– Resource-Intensive: Conducting FMEA can be time-consuming and requires skilled personnel.
	– Subjectivity: Risk assessments and RPNs may vary based on individual judgments and expertise.
Key Takeaway	Failure Mode and Effects Analysis (FMEA) is a structured approach to identify potential failure modes, their causes, and their effects on products, processes, or systems. By systematically assessing risks and prioritizing mitigation efforts, FMEA helps organizations improve reliability, safety, and performance. It finds applications in manufacturing, engineering, healthcare, and various industries where risk management is critical. However, it can be resource-intensive and subject to individual judgments.

Understanding a failure mode and effects analysis

History is littered with examples of product recalls because of poorly designed products or processes.

One such example is the Takata airbag recall, the largest automotive recall in the world affecting an estimated 100 million vehicles.

The recall was caused by design and manufacturing problems which lead to the airbag becoming highly explosive if exposed to high humidity.

Developed in the 1950s, the failure mode and effects analysis is one the earliest methodologies of its kind.

It enables organizations to anticipate a range of potential failures during the design stage.

When conducting a FMEA, the team is prompted to evaluate the:

Steps in the process.
Failure modes – what could go wrong?
Failure causes – why would the failure occur?
Failure effects – what would be the consequences of failure occurrence?

Significance of FMEA

FMEA offers several significant advantages and benefits:

1. Risk Mitigation:

FMEA helps organizations identify and mitigate potential risks and failures early in the design or process development stage.

2. Enhanced Reliability:

By addressing failure modes proactively, FMEA contributes to improved product and process reliability.

3. Cost Reduction:

Identifying and addressing failure modes early can prevent costly recalls, rework, or warranty claims.

4. Safety Improvement:

FMEA is particularly critical in safety-critical industries, such as healthcare and aerospace, where it helps prevent accidents and injuries.

5. Process Optimization:

FMEA can lead to process improvements and optimization, resulting in higher efficiency and quality.

6. Regulatory Compliance:

In regulated industries, FMEA is often a requirement to demonstrate safety and reliability compliance.

Conducting a failure mode and effects analysis

A FMEA should be performed using a simple spreadsheet. In general terms, here is how a typical business might run the analysis:

Step 1 – Assemble a team

Start by creating a cross-functional team with a diverse range of knowledge about the process or product to be analyzed.

This may include manufacturing, quality control, customer service, maintenance, or purchasing.

Step 2 – Define the scope

In other words, is the FMEA being used for a concept, system, process, or design? Where are the boundaries and what is the level of detail required?

Process steps should be listed in rows at the far left of the spreadsheet.

Step 3 – List failure mechanisms

List the ways that each process step can fail through brainstorming or the reviewing of existing documentation.

This list should be exhaustive and many steps will have multiple avenues to failing.

Then, repeat the same process for the potential effects of each failure.

Step 4 – Assign severity rankings

Using a scale of 1 to 10, rank the severity of the potential effect on the customer.

A score of 9 would denote a high-impact event, while a score of 2 would denote a low-impact event.

Step 5 – List and score potential causes of failure

How could the failure effect occur?

For example, a bank customer could become dissatisfied (failure effect) because of an ATM running out of cash (failure cause).

For each potential failure cause, rank it according to how frequently it is likely to occur.

Rare occurrences receive low scores, while frequent events receive higher scores.

Step 6 – List and score current process controls

What are the existing controls that prevent the failure mode from occurring? Some controls may only detect failure modes after they occur.

Returning to the previous example, the bank might receive an internal alert that cash in the ATM is running low.

Each control should then be scored according to its ability to detect the occurrence of a failure event.

A failure event that is easily detected by a control is given a low score while a higher score is assigned to an inconspicuous failure event.

Step 7 – Determine the risk priority number

The risk priority number (RPN) is the overall risk score of an event. It can be calculated by multiplying the severity, occurrence, and detection scores together.

A process step with a higher RPN demands immediate attention. Lower RPN steps are at less risk of failure.

Step 8 – Propose recommended courses of action

Lastly, the team should propose a course of action for:

All process steps with a high RPN.
All failure effects with a severity score of 9 or 10, or those effects associated with customer safety or regulation.
All process steps scoring highly for both severity and occurrence – otherwise known as high criticality combinations.

Actions that reduce risk ultimately involve eliminating the failure or addressing the cause of the failure.

Processes can also be improved by increasing design tolerance and reducing variation in process output quality.

Lastly, controls can be improved by making processes and tools mistake-proof (often achieved through automation).

Enhanced inspection and evaluation techniques can also increase control effectiveness.

Failure mode and effects analysis example

Consider the FMEA analysis for a company that designs bicycle brake cables. The assembled team defines three potential failure models and their associated effects:

Cable breaks (potential failure mode) – bicycle rider is not able to close brake caliper to reduce speed, which may result in an accident and/or injury (failure effect).
Cable binds – bicycle rider is required to use more force to close brake calipers because of increased friction between brake cable and sheath.
Cable slips at brake lever locking nut or caliper – brake caliper does not close when correct amount of force is applied to lever. This may result in less friction between the brake pads and wheels and a possible accident and/or injury.

Next, the team scores each failure mode for its potential severity (step four in the process outlined above):

Cable breaks – 10.
Cable binds – 6.
Cable slips at break lever locking nut or caliper – 9.

Then, the team discusses how each failure could arise and then score it according to how frequently it may occur.

Remember, frequent events receive higher scores than events perceived to be rarer.

Cable breaks – nylon abrasion due to improper material use (2), nylon becomes brittle because of low relative humidity or repeated bending under load (4).
Cable binds – cable that is bent or kinked because of misalignment (5), poor or non-existent lubrication between sheath and cable (2).
Cable slips at break level locking nut or caliper – the diameter of the brake cable is too small to be secure after the locking nut is engaged (7).

In step six, the team lists the current controls that either prevent a failure mode from occurring or detect it after it has occurred.

Each control is also scored according to how well it detects a failure event, with lower scores associated with events that are more easily detected.

Nylon abrasion due to improper material use – choice of cable material based on applicable American National Standards Institute (ANSI) criteria, factory cable strength test (1).
Nylon becomes brittle because of low relative humidity or repeated bending under load – laboratory examination for evidence of cracking (4).
Nylon cable that is bent or kinked because of misalignment – design guide for nylon cable material, inspection of all new cable material (2).
Poor or non-existent lubrication between sheath and cable – design guide for cable lubrication, perform brake lever effort test (1).
The diameter of the brake cable is too small to be secure after locking nut is engaged – undertake brake mechanism tolerance study, perform brake calibration test (2).

Now it is time to calculate the RPN by multiplying the severity, occurrence, and detection for each event:

Cable breaks because of nylon abrasion – 10 x 2 x 1 = 20.
Cable breaks because nylon becomes brittle – 10 x 4 x 4 = 160.
Cable binds because of bend or kink in cable – 6 x 5 x 2 = 60.
Cable binds because of inadequate lubrication – 6 x 2 x 1 = 12.
Cable slips because of small cable diameter – 9 x 7 x 2 = 126.

From these results, failure effects that result in accident or injury to the rider should be prioritized.

A cable that slips because of a smaller diameter is a high criticality combination because it scores relatively highly for both severity and occurrence.

In this case, one potential way to improve this process would be to redesign the cable locking mechanism from scratch.

Case Studies

Food Manufacturing Company: Chocolate Bar Production

Step 1 – Assemble a team:

Production manager, quality assurance manager, maintenance technician, and customer service representative.

Step 2 – Define the scope:

Analysis of the chocolate bar molding process.

Step 3 – List failure mechanisms:

Chocolate doesn’t set properly, presence of foreign contaminants, uneven mixture of ingredients.
Effects: Dissatisfied customers, potential health risks, inconsistent taste.

Step 4 – Assign severity rankings:

Chocolate not setting (7), contaminants (10), uneven mixture (6).

Step 5 – List and score potential causes:

Improper temperature (5), unclean equipment (8), malfunctioning mixer (4).

Step 6 – List and score current process controls:

Regular thermometer checks, equipment cleaning schedule, mixer maintenance checks.
Detection scores: 3, 2, 4 respectively.

Step 7 – Determine RPN:

Improper temperature: 7 x 5 x 3 = 105.
Contaminants: 10 x 8 x 2 = 160.
Uneven mixture: 6 x 4 x 4 = 96.

Step 8 – Recommended actions:

Improved temperature monitoring, stricter cleaning protocols, and enhanced mixer maintenance.

Online E-commerce Platform

Step 1 – Assemble a team:

IT specialist, customer service representative, quality assurance tester, and security expert.

Step 2 – Define the scope:

Analysis of the checkout process.

Step 3 – List failure mechanisms:

System crashes during checkout, incorrect billing, unauthorized access.
Effects: Lost sales, financial discrepancies, potential data breaches.

Step 4 – Assign severity rankings:

System crash (8), incorrect billing (7), unauthorized access (10).

Step 5 – List and score potential causes:

Server overload (6), software bug (5), weak security measures (9).

Step 6 – List and score current process controls:

Server monitoring tools, routine software testing, two-factor authentication.
Detection scores: 4, 3, 5 respectively.

Step 7 – Determine RPN:

System crash: 8 x 6 x 4 = 192.
Incorrect billing: 7 x 5 x 3 = 105.
Unauthorized access: 10 x 9 x 5 = 450.

Step 8 – Recommended actions:

Enhance server capacity, rectify software glitches, strengthen security measures.

Airline Industry: Flight Booking Process

Step 1 – Assemble a team:

Flight operations expert, IT specialist, customer service manager, and a financial controller.

Step 2 – Define the scope:

Analysis of online flight booking.

Step 3 – List failure mechanisms:

Double booking of seats, wrong flight details provided, payment failures.
Effects: Inconvenienced passengers, lost trust, revenue loss.

Step 4 – Assign severity rankings:

Double booking (9), wrong flight details (8), payment failure (7).

Step 5 – List and score potential causes:

System synchronization issues (8), database errors (6), payment gateway issues (7).

Step 6 – List and score current process controls:

Real-time system checks, data validation protocols, payment gateway monitoring.
Detection scores: 3, 4, 2 respectively.

Step 7 – Determine RPN:

Double booking: 9 x 8 x 3 = 216.
Wrong flight details: 8 x 6 x 4 = 192.
Payment failure: 7 x 7 x 2 = 98.

Step 8 – Recommended actions:

Improve system synchronization, enhance database accuracy, and coordinate with payment service providers.

Key takeaways

A failure mode and effects analysis is a structured, evaluative approach to identifying failures in a product or process.
A failure mode and effects analysis forces teams to critically evaluate each step in a process. This is achieved by considering the modes, causes, and potential effects of process failures.
A failure mode and effects analysis can be performed using spreadsheet software. Teams must assign weighted scores to a range of variables and focus their efforts on process steps with the highest risk of failure.

Key Highlights

Failure Mode and Effects Analysis (FMEA): A structured approach to identify design failures in products or processes, allowing organizations to anticipate potential failures during the design stage.
History of FMEA: Developed in the 1950s, it helps prevent product recalls and improve design quality.
FMEA Process Steps:
1. Assemble a Team: Create a cross-functional team with diverse knowledge about the process/product to be analyzed.
2. Define the Scope: Determine the focus of the analysis and set boundaries for the evaluation.
3. List Failure Mechanisms: Brainstorm potential failure modes for each process step and their associated effects.
4. Assign Severity Rankings: Rank the severity of potential failure effects on customers using a scale of 1 to 10.
5. List and Score Potential Causes of Failure: Identify the reasons for each failure effect and rank their likelihood of occurrence.
6. List and Score Current Process Controls: Evaluate existing controls to prevent or detect failures and score their effectiveness.
7. Determine the Risk Priority Number (RPN): Calculate the overall risk score by multiplying severity, occurrence, and detection scores.
8. Propose Recommended Courses of Action: Develop action plans to address high-risk process steps and failure effects.
Example: Bicycle brake cables FMEA analysis:
- Identified failure modes and effects for cable breaks, cable binds, and cable slips.
- Scored severity, occurrence, and detection for each failure mode.
- Calculated RPN to prioritize high-risk failures.
- Recommended actions to improve critical process steps and mitigate risks.
Benefits of FMEA: Allows critical evaluation of each process step, helps identify potential failures, and enables continuous improvement.