FMEA Explained: 2021 Guide

20 May 2021 by Jimmy Nguyen

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Table of Contents:

  1. What is FMEA?
  2. Why is FMEA important?
  3. When is FMEA necessary?
  4. How the FMEA process works.
  5. Digitizing the FMEA process
  6. Conclusion

What is FMEA?

FMEA stands for Failure Mode and Effects Analysis.

In the manufacturing industry, as the complexity of a product increases, so does the probability of error as work transitions downstream from design to manufacturing to product and/or service.

FMEA is a proactive qualitative and systematic risk analysis that identifies and ranks all potential problems (failure mode) and their repercussions (effects analysis) to ensure a reliable and repeatable product and process.

Failure Mode and Effects Analysis is a living document that:

  1. Records all potential product and process failures.
  2. Minimizes risk of product and process failures through corrective action.
  3. Documents results and insights for current and future product and process success.

FMEA is part of the five Core Tools for effective quality management with APQP, PPAP, MSA, and SPC being the other core tools.

Types of FMEA:

  1. Design FMEA (DFMEA)
  2. Process FMEA (PFMEA)
  3. Functional FMEA (FFMEA) / System FMEA (SFMEA)
  4. Software FMEA

Why is FMEA important?

FMEA is a preemptive look into identifying potential problems earlier in the design process.

Scrap, rework, defects, retesting, and recalls are expensive.

However, they are exponentially more costly as corrective action is taken further in the product lifecycle. For example, corrective action in the operations phase is at a minimum 29X more expensive than in the design phase.

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The Cost of Poor Quality (COPQ) measures costs associated with product and process failures. Top manufacturers have a COPQ score of around 1% whereas poor performers have a COPQ score of around 5%.

To put that into perspective, if two manufacturers make $100 million in revenue a year, the one with a 1% COPQ score will pay $1 million in scrap and rework costs whereas the other with a 5% COPQ score will pay $5 million.

Compound that by the number of years and that’s money left on the table that could be well spent on other important initiatives.

Although FMEA can’t anticipate all failures, it greatly reduces the frequency and impact of risks.

5 Benefits of FMEA

  1. Improved product and process reliability, quality, and safety.
  2. Identify and eliminate or reduce potential product and process failures.
  3. Document and organize shared knowledge for current and future use.
  4. Reduce costs and problems later in the product lifecycle.
  5. Better customer satisfaction.

When is FMEA necessary?

FMEA is typically used for the following reasons:

  1. Development of new product or process.
  2. Changes to an existing product or process.
  3. Regular checkup of product and process integrity.
  4. New improvement goals for product or process.
  5. New regulations.
  6. Change of product function outside of original scope.
  7. Deeper look into analyzing failures of product or process.

How the FMEA process works

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The FMEA process is composed of a cross-functional collaborative team composed of members in engineering, manufacturing, quality, operations, procurement, and other functions with a process manager responsible for managing the project.

The FMEA process (by AIAG and VDA standards) is typically defined in seven steps. Each step is sequential, so the previous step creates an output that serves as the next step’s input.

Here is the FMEA 7-Step Process:

System Analysis

  • Step 1: Planning & Preparation
  • Step 2: Structure Analysis
  • Step 3: Function Analysis

Failure Analysis and Risk Mitigation

  • Step 4: Failure Analysis
  • Step 5: Risk Analysis
  • Step 6: Optimization

Risk Communication

  • Step 7: Result Documentation

Step 1: Planning & Preparation

In Planning & Preparation, the team defines the purpose and definition of the scope, sets boundaries of the analysis (what needs to be included or excluded), and establishes the foundation for the entire FMEA process.

Project planning can be broken down into 5 topics known as the 5 T’s:

  1. InTent: Why are we doing the FMEA?
  2. Timing: When is this due?
  3. Team: Who needs to be on the team?
  4. Task: What work needs to be done?
  5. Tools: How do we conduct the analysis?

Step 2: Structure Analysis

In Structure Analysis, the system structure is further clarified for technical analysis.

The boundaries set up in Planning & Preparation are analyzed to identify which systems, sub-systems, and/or components will be part of the FMEA.

For Design FMEA (DFMEA), interfaces (physical connection, material exchange, energy transfer, data exchange, and human-machine), interactions, and close clearances are identified.

For Process FMEA (PFMEA), process steps and sub-steps are identified.

Additional tools to support the Structure Analysis are provided such as a structure tree, block diagram, boundary diagram, flow diagram, or other visualization tools.

Step 3: Function Analysis

In Function Analysis, the product and process functions are explored as well as the criteria on how to evaluate the performance of functions.

The system elements done in the Structure Analysis are individually analyzed of its functions and corresponding requirements.

For DFMEA, functions and requirements are identified by next higher level function (highest level of integration within scope of analysis), focus element (item in focus), and next lower level function (element that is next level down the structure from focus element).

For PFMEA, functions and requirements are identified by function of process item system, function of process step and product characteristic, and function of the process work element and process characteristic. 

Step 4: Failure Analysis

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In Failure Analysis, the team establishes a Failure Chain through the cause-and-effect relationships of these 3 categories:

  1. Failure mode: An item/element that fails to meet its intended function.
  2. Failure effect: The consequences.
  3. Failure cause: Why the failure mode would happen.

Types of potential failure modes include:

  1. Loss of function
  2. Degradation of function
  3. Intermittent function
  4. Partial function
  5. Unintended function
  6. Exceeding function
  7. Delayed function

Step 5: Risk Analysis

In Risk Analysis, root cause analysis is estimated and prioritized by evaluating these 3 categories:

  1. Severity: How badly does this affect the customer?
  2. Occurrence: How often will it happen?
  3. Detection: How easy is it to detect?

Each risk category has a scoring matrix from 1 to 10 with 1 being low-risk to 10 being high-risk.

In a previous FMEA risk analysis, each score is multiplied together (Severity x Occurrence x Detection) to produce a Risk Priority Number (RPN). However, RPN alone is not adequate since it gives equal weight to Severity, Occurrence, and Detection.

In a newer FMEA risk analysis, priority is given to Severity first, then Occurrence, and then Detection, creating better decisions to prioritize risks.

This new method is called Action Priority (AP) and accounts for all 1,000 combinations of Severity, Occurrence, and Detection and is ranked by three classifications:

  1. Priority High (H): REQUIRED to identify appropriate action to improve prevention and/or detection controls or justify why current controls are adequate.
  2. Priority Medium (M): SHOULD identify appropriate actions to improve prevention and/or detection controls or justify why current controls are adequate.
  3. Priority Low (L): COULD identify appropriate action to improve prevention and/or detection controls.

Risks with a Severity score of 7 and above are predominately high AP.

Example of AP Table:

Action Priority (AP) for DFMEA and PFMEA
Action Priority is based on combinations of Severity, Occurrence, Detection ratings to prioritize actions for risk reduction. Blank until filled by user
Effect S Prediction of Failure Cause Occurring O Ability to Detect D Action Priority (AP) Comments
Product or Plant Effect Very High 9-10 Very high 8-10 Low - Very Low 7-10 H  
Moderate 5-6 H  
High 2-4 H  
Very high 1 H  
High 6-7 Low - Very Low 7-10 H  
Moderate 5-6 H  
High 2-4 H  
Very high 1 H  
Moderate 4-5 Low - Very Low 7-10 H  
Moderate 5-6 H  
High 2-4 H  
Very high 1 M  
Low 2-3 Low - Very Low 7-10 H  
Moderate 5-6 M  
High 2-4 L  
Very high 1 L  
Very low 1 Very high -Very low 1-10 L  

Step 6: Optimization

In Optimization, the team develops a plan of action to mitigate risks and assess the effectiveness of the optimization actions.

Actions are divided into 2 categories: prevention and detection.

Assignments of responsibilities and deadlines are given.

After actions have been performed, the team reviews the results to rescore the risks.

Step 7: Result Documentation

In Results Documentation, the FMEA is summarized, documented, and communicated to the team and stakeholders.

The FMEA report includes summary of scope, identification of high-risk failures, the corrective actions taken and their effectiveness, and insights/plans for current and future processes.

The results documentation is to summarize and communicate the results of the FMEA activity.

5 Common FMEA Mistakes:

  1. Performing FMEA too late: The earlier in design phase the better.
  2. Accountability of required actions: Have clear ownership for parts of the process.
  3. Setting it and forgetting it: FMEA is a living document of continuous improvement.
  4. Poor documentation: Useful documentation limits redundancies and leaves insight for future teams.
  5. Poor root cause identification: Due diligence confirms a proper solution and not wasted efforted and continued defects.

Digitizing the FMEA process

FMEA is a lot of work.

Some challenges include the considerable number of documents, spreadsheets, and people involved--especially with constantly updating data as the complexity of the project evolves.

The traditional drawing-based, paper-based workflow leads to increased laborious and repetitive manual work (especially repeat data entry), a lack of organization and consistency for all FMEAs, and a need for a structured knowledge base for current and future insights.

Digitization is the future here.

MBD Benefits

A model-based approach called MBD (model-based definition) uses a single source of truth: the 3D CAD model + PMI (product manufacturing information) to store the geometry and manufacturing data to build and measure a part that could be used downstream throughout entire the supply chain.

This model contains a large portion of the product definition and requirements (e.g. information regarding significant characteristics, etc.) which follows the FMEA analysis. Additional data like risk information and process plans can also be generated using requirement management software tools or MBDVidia

When you have a digital source for your data which includes production definition and tolerances (MBD), product requirements and risks, process plan info, etc., then it all becomes streamlined significantly.

The results: automatic time-savings and a more repeatable and faster FMEA process.

The ISO QIF standard provides the ability to digitize the MBD, Control Plan (from FMEA), measurement results (PPAP and MSA), and measurement statistics (SPC). QIF is rapidly being adopted by the industry as the digital backbone of the MBD transformation in the manufacturing industry.

If FMEA unifies early risk analysis (the what), the MBD-based FMEA process unifies the risk analysis process (the how).

Conclusion

FMEA evaluates potential failure through 5 questions:

  1. What can go wrong?
  2. Why would that happen?
  3. What are the consequences?
  4. How can that be prevented?
  5. What insights apply to current and future scenarios?

When properly implemented and documented, current and future teams can detect failure earlier in the manufacturing process.  This creates immediate time and cost savings upfront vs the exponential time and cost expenses when fixed later in the product lifecycle.  


Have questions about FMEA?

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Capvidia is a leader in MBD-based workflows and all things pertaining to digital transformation in the manufacturing industry.


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