Guide to Failure Mode and Effects Analysis (FMEA)

What is a Failure Mode and Effect Analysis (FMEA)?

Failure Mode and Effect Analysis (FMEA), also known as “Potential Failure Modes and Effects Analysis” as well as “Failure Modes, Effects and Criticality Analysis (FMECA)” is a systematic method for identifying?possible failures that pose the greatest overall risk for a process, product, or?service which could include failures in design, manufacturing or assembly lines. A process analysis tool depends on identifying:

1. Failure mode: One of how a product can fail; one of its?possible deficiencies or defects
2. Effect of failure: The consequences of a particular mode of failure
3. Cause of failure: One of the possible causes of an observed mode of?failure
4. Analysis of the failure mode: Its frequency, severity, and chance of?detection

Failure Mode and Effects Analysis (FMEA) is a robust and systematic approach to anticipate, prioritize, and mitigate risks. It helps organizations preemptively address possible hitches in their processes or products, paving the way for higher safety, improved quality, and increased customer satisfaction.

Despite its complexity, the returns it offers in risk mitigation are invaluable, making FMEA a tool of choice for organizations keen on proactive problem-solving and continuous improvement. It’s not just about solving problems – it’s about predicting and preventing them. That is the power of FMEA.

Types of FMEA

There are currently two types of FMEA: Design FMEA (DFMEA) and Process FMEA (PFMEA).

Design FMEA

Design FMEA (DFMEA) is a methodology used to analyze risks associated with a new, updated or modified product design and explores the possibility of product/design malfunctions, reduced product life, and safety and regulatory concerns/effects on the customer derived from:

1. Material Properties (Strength, Lubricity, Viscosity, Elasticity, Plasticity, Malleability, Machinability etc.)
2. The Geometry of the Product (Shape, Position, Flatness, Parallelism,
3. Tolerances/Stack-Ups
4. Interfaces with other Components and/or Systems (Physical Attachment/Clearance; Energy Transfers; Material Exchange or Flow i.e Gas/Liquid; Data Exchanges – Commands, Signals, Timings)
5. Engineering Noise including User Profile, Environments, Systems Interactions & Degradation

Process FMEA

Process FMEA (PFMEA) is a methodology used to discovers risks associated with process changes including failure that impacts product quality, reduced reliability of the process, customer dissatisfaction, and safety or environmental hazards derived from the 6Ms:

1. Man: Human Factors / Human Error
2. Methods: Methods involved in processes of product/service including assembly lines, supply chains and communications standards
3. Materials: Materials used in the process
4. Machinery: Machines utilized to do the work
5. Measurement: Measurement systems and impact on acceptance
6. Mother Earth: Environment Factors on process performance

Why Perform Failure Mode and Effects Analysis (FMEA)

Historically, the sooner a failure is discovered, the less it will cost. If a failure is discovered late in product development or launch, the impact is exponentially more devastating.

FMEA is one of many tools used to discover failure at its earliest possible point in product or process design. Discovering a failure early in Product Development (PD) using FMEA provides the benefits of:

• Multiple choices for Mitigating the Risk
• Higher capability of Verification and Validation of changes
• Collaboration between design of the product and process
• Improved Design for Manufacturing and Assembly (DFM/A)
• Lower cost solutions
• Legacy, Tribal Knowledge, and Standard Work utilization

Ultimately, this methodology is effective at identifying and correcting process failures early on so that you can avoid the nasty consequences of poor performance.

When to Perform Failure Mode and Effects Analysis (FMEA)

There are several times at which it makes sense to perform a Failure Mode and Effects Analysis:

• When you are designing a new product, process or service
• When you are planning on performing an existing process in a different way
• When you have a quality improvement goal for a specific process
• When you need to understand and improve the failures of a process

In addition, it is advisable to perform an FMEA occasionally throughout the lifetime of a process. Quality and reliability must be consistently examined and improved for optimal results.

How Does FMEA Work?

Once each failure mode is identified, the data is analyzed, and three factors are?quantified:

• Severity (SEV):?The severity of the effect of the failure as felt by the?customer (internal or external). The question may be asked, “How?significant is the impact of the effect on the customer?”
• Occurrence (OCC):?The frequency which each failure or potential cause?of the failure occurs. The question may be asked, “How likely is the cause?of the failure mode to occur?”
• Detection (DET):?The chance that the failure will be detected before it?affects the customer internal or external). The question may be asked,?“How likely will the current system detect the failure mode if it occurs, or?when the cause is present?”

Risk Priority Number

The information inputted into an FMEA is calculated, and the output is a Risk Priority Number (RPN). The RPN is calculated by multiplying the severity times the occurrence times the detection (RPN = Severity x Occurrence x Detection) of each recognized failure mode.

Each of the three factors is scored on a 1 (Best) to 10 (Worst) scale. The combined?impact of these three factors is the Risk Priority Number (RPN). This is the?calculation of the risk of a particular failure mode and is determined by the following?calculation:

RPN = SEV x OCC x DET

How to Construct an FMEA: FMEA Procedure

Step 1: Provide background information on the FMEA:

• Identify a name or item name for the FMEA
• Identify the team participating in development of the FMEA
• Record when the FMEA was first created and subsequent revisions
• Identify and record the owner or preparer of the FMEA

Step 2: List the process steps, variable or key inputs.

Step 3: Identify potential failure modes.

• A failure mode is defined as the manner in which a component, subsystem, process, etc. could potentially fail. Failure?modes can be identified through existing data, or by brainstorming possible?instances when the process, product, or service may fail.

Step 4: Describe the potential effect(s) of failure modes.

Answer the question—if the?failure occurs what are the consequences? Examples of failures include:

• Incorrect data
• Inoperability or stalling of the process
• Poor service

Step 5: Identify the severity of the failure using the following table.

Since this?rating is based on the team’s perception, it can also be arbitrary unless?backed up with data.

FMEA Severity Rating Factors

Step 6: Identify potential cause(s) of failure.

Describe the causes in terms of?something that can be corrected or can be controlled.

Step 7: Rate the likelihood of the identified failure cause occurring.

Use the?following table to determine ranking.

FMEA Probability Rating Factors

Step 8: Describe the current process controls to prevent the failure mode—controls?that either prevent the failure mode from occurring or detect the failure?mode, should it occur.

1. First Line of Defense—Avoid or Eliminate Failure Cause(s)
2. Second Line of Defense—Identify or Detect Failure Earlier
3. Third Line of Defense—Reduce Impacts/Consequences of Failure

*Design Verification Testing (DVT) is a test conducted when designing new products or?services to verify that the optimal process design performs at the level specified by?customer requirements (CTQs). DVT is a methodical approach used to identify and resolve?problems before finalizing the process for new products or services.

Step 9: Next, rank the likelihood that the failure cause will be detected. Use the?following table.

FMEA Detection Rating Factors

Step 10: Multiply the three ratings to determine the Risk Priority Number (RPN)?for each potential failure mode.

These numbers will provide the team with?a better idea of how to prioritize future work addressing the failure modes?and causes.

Step 11: Use the RPN to identify and prioritize further actions and who is?responsible for completing those actions and by what date.

Document?in the “actions taken” column only completed actions. As actions are?completed there is another opportunity to recalculate the RPN and re-prioritize?your next actions.

FMEA Action Planning

FMEA Relationship to Problem Solving

The Failure Modes in an FMEA are equivalent to the Problem Statement or Problem Description in Problem Solving. Causes in an FMEA are equivalent to potential root causes in Problem Solving. Effects of failure in an FMEA are Problem Symptoms in Problem Solving. More examples of this relationship are:

• The problem statements and descriptions are linked between both documents. Problem-solving methods are completed faster by utilizing easy-to-locate, pre-brainstormed information from an FMEA.
• Possible causes in an FMEA are immediately used to jump-start Fishbone or Ishikawa diagrams. Brainstorming information that is already known is not a good use of time or resources.
• Data collected from problem-solving is placed into an FMEA for future planning of new products or process quality. This allows an FMEA to consider actual failures, categorized as failure modes and causes, making the FMEA more effective and complete.
• The design or process controls in an FMEA are used in verifying the root cause and Permanent Corrective Action (PCA).
• The FMEA and Problem-Solving reconcile each failure and cause by cross-documenting failure modes, problem statements and possible causes.

Reference

1. How to Conduct an FMEA Analysis | Lucidchart
2. FMEA | Failure Mode and Effects Analysis | Quality-One
3. Guide to Failure Mode and Effects Analysis (FMEA) | Reliability
4. What is FMEA? Failure Mode & Effects Analysis | ASQ
5. Guide to Failure Mode and Effect Analysis - FMEA | Juran Institute, An Attain Partners Company