IE 5356 Biomedical Innovation
Failure Mode and Effects Analysis (FMEA)
Instructor: Dr. George Z. Tan
Medical Device Failure – The Bleeding Edge (2018)
Failure Mode and Effects Analysis (FMEA): What
Begun in the 1940s by the U.S. military, failure modes and effects analysis
(FMEA) is a step-by-step approach for identifying all possible failures in a
design, a manufacturing or assembly process, or a product or service.
•Failure modes - the ways, or modes, in which something might
fail. Failures are any errors or defects, especially ones that affect
the customer, and can be potential or actual.
•Effects analysis - studying the consequences of those failures.
FMEA: Why
• The purpose of the FMEA is to take actions to eliminate or reduce failures,
starting with the highest-priority ones.
• Failure modes and effects analysis also documents current knowledge and
actions about the risks of failures, for use in continuous improvement.
• Ideally, FMEA begins during the earliest conceptual stages of design and
continues throughout the life of the product or service.
FMEA: When
• When a process, product, or service is being designed or redesigned, after quality
function deployment (QFD)
• When an existing process, product, or service is being applied in a new way
• Before developing control plans for a new or modified process
• When improvement goals are planned for an existing process, product, or service
• When analyzing failures of an existing process, product, or service
• Periodically throughout the life of the process, product, or service
FMEA: When
The Risk categories during the lifecycle of medical device product
FMEA: How
1.
2.
3.
4.
5.
Break down the system, design, or process into its component elements.
Review each element systematically and uncover all possible ways it could fail.
Analyze the effects and likely causes of each failure.
Rank each potential effect based on user-defined risk criteria.
Decide how to detect, eliminate, or minimize the most critical risks. Then,
outline a plan of recommended actions to implement to reduce the risks of
failure effects.
6. Return to the original risk levels and revise them based on the completed
action items in the plan to ensure that the risk goals have been met.
The Process of Risk Management
FMEA: Key Terms
RISK - combination of the probability of occurrence of harm and the severity of that harm
HAZARD - potential source of harm
HAZARDOUS SITUATION - circumstance in which people, property, or the environment are exposed
to one or more hazard(s)
HARM - physical injury or damage to the health of people, or damage to property or the
environment
SEVERITY - measure of the possible consequences of a hazard
Risk Factors
◦ Probability of occurrence
◦ Range of possible outcomes (impact or amount at stake
◦ Expected Timing of event
◦ Anticipated frequency of risk events from that source
FMEA: Risk Metrics Diagram
● If the potential risk event appears in the
critical region or high region, it should be
prevented without any care about the cost.
● If the potential risk event appears in the
medium region, it should be prevented at a
reasonable cost.
● If the potential risk event appears in the
low region, it should be prevented following
some reasonable steps or some measures
should be taken to reduce its negative
impacts.
Risk Priority Number
Three groups of data can be got through FMEA process
Severity (S)
An assessment of the significance of the failure mode’s effect on item operation
Occurrence (O) or Probability (P)
The frequency or probability of occurrence of each failure mode
Detection (D)
The risk that the failure will escape detection.
RPN (risk priority number) is a product of these three groups of data
RPN=S×O×D
Risk Priority Number
Score
Occurrence
Severity
Detection
1
Very unlikely to occur
Very low—will not affect the
process
Certain—fault will be caught
on test
2/3
Unlikely to occur
Low—may affect the process
High
4/5
May occur about half of the
time
Medium—slightly affect the
process
Moderate
6/7/8
Likely to occur
High—mostly affect the process
Low
9/10
Very likely to occur
Very high—definitely affect the
process
Fault will be passed to
customer undetected
The Major Process of FMEA Method
Diagramming Techniques
Cause and Effect Diagrams
◦ Also known as Ishikawa or fishbone
Potential Causes
Testing
Inadequate
Time
Effect
Project
Prioritization
Product
Delivered
Late
Personnel
Materials
Insufficient
Resources
Bad Specs
FMEA Example
15
Risk Register
List of
◦ Identified risks
◦ Potential responses
◦ Root causes
Updated risk categories (if required)
Probability and Impact Plots
Rate each risk on scales then plot on
matrix
Develop mitigation technique for risks
above tolerance
Add




Probability and Impact Matrix results
Perform quality check on results
Categorize the risks to make them easier to handle
Perform urgency assessment to determine which
risk need immediate attention
Risk Control
Overall Strategies
Negative Risks (or Threats)
◦ Avoid
◦ Transfer
◦ Mitigate
◦ Acceptance
Positive Risks (or Opportunities)
◦ Exploit
◦ Share
◦ Enhance
◦ Acceptance
Summary
20