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Categorization of Failures
SMALL UNMANNED SYSTEMS BUSINESS EXPOSITION 2015Karen Rayment, MSEE, MBA, P.E., CFEI, PMP510-775-3394 Mobile
KRayment@CASEForensics.com
April 18, 2023Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Categorization of Failures: Overview and Basic Concepts
1. Definitions- Categorize the Failure First, if Possible: Legal Framework
2. FA Tips and Techniques: Put up Walls!3. Business Considerations
a. Product Lifecycle to Help Clarify Remediesb. Artifacts of Catastrophic Failures- Business
and Human Factors Losses
April 18, 2023 2Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Categorization of Failures: Overview and Basic Concepts
1. Definitions- Categorize the Failure First, if Possible: Legal Framework
2. FA Tips and Techniques: Put up Walls!3. Business Considerations
a. Product Lifecycle to Help Clarify Remediesb. Artifacts of Catastrophic Failures- Business
and Human Factors Losses
April 18, 2023 3Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Why We Study Framework
◊ “The biggest problem in communication is the illusion that it has taken place.”
- George Bernard Shaw
April 18, 2023 4Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
1. Definitions- Categorize the Failure First, if Possible, within the Product Liability Legal Framework
April 18, 2023Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Failures within the Product Liability Framework – Important Distinctions1. Design Defect: Is a product inherently
dangerous, due to the design specifications, for its intended purpose?
2. Manufacturing Defect: Were sub-standard materials or processes used in producing the unit in question, but design is according to specifications?
3. Foreseeable Product Abuse: What would a “reasonable person” do within the intended use environment?
April 18, 2023 6Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Categorization of Failures:Overview and Basic Concepts
1. Definitions- Categorize the Failure First, if Possible: Legal Framework
2. FA Tips and Techniques: Put up Walls!3. Business Considerations
a. Product Lifecycle to Help Clarify Remediesb. Artifacts of Catastrophic Failures- Business
and Human Factors Losses
April 18, 2023 7Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
2. FA Tips and Techniques: Put up Walls!
April 18, 2023
Available Energy, Failure Mode, and then Effects
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
3. FA Tips and Techniques: Put up the Walls!◊ Engineers MUST set aside emotional
language, such as customer reports◊ Engineers MUST make a distinction
between a failure and its effects◊ Engineers should always follow the
standard Scientific Method process flowNOTE: With a working hypothesis, additional questions will
fall out- do one iteration of Scientific Method per question!!!
April 18, 2023 9Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Engineers MUST Set Aside Emotional Language, Such as in Customer Reports!
April 18, 2023 10
◊ When products fail, people get panicky◊ When people get panicky and don’t
understand something, they tend to exaggerate the effects of failure
◊ CASE STUDY EXAMPLE 1 - Customer comment was, “You almost burned my house down, and my family almost died!”
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Engineers MUST Set Aside Emotional Language, Such as in Customer Reports!
April 18, 2023 11Consumer Product Field Failures © Case Forensics 2014 – All Rights Reserved
◊ The wall power supply had experienced overheating, and had a short between power and ground traces, which caused a SELF-EXTINGUISHING, SHORT DURATION, LOCALIZED FAULT
◊ NOT ENOUGH AVAILABLE ENERGY TO START A FIRE!
◊ Energy Considerations Include: Available Mechanical & Electrical Energy, and Time
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Engineers MUST Set Aside Emotional Language, Such as in Customer Reports!
April 18, 2023 12
◊ CASE STUDY RESULTS: The wall power supply experienced a FAST, SELF-EXTINGUISHING, LOCALIZED FAILURE
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Engineers MUST Make a Distinction between a Failure and its Effects!
April 18, 2023 13
◊ We can’t both replicate root cause, and study field failure effects during the same iteration of an experiment – lose patterns
◊ It is much easier to form a hypothesis about root cause based upon observations of effects, and then replicate effects and backtrack to prove a hypothesis
◊ It is rare when a lab-created fault will EXACTLY replicate a field failure – don’t waste your time and effort
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Engineers should Always Follow the Standard Scientific Method Process
April 18, 2023 14Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
CASE STUDY EXAMPLE 2 - Separate Cause and Effects: Intermittent CPU Failures
From Legal Definitions - Categorize the Failure First, if Possible: Most Likely a Manufacturing Defect – Why?
◊ Product Lifecycle in the Market – Product has been in Field Use for 3.5 Years, and CPU Design is Older than the Product
◊ FA Tips and Techniques: Put up the Wall! Hypothesis: Intermittent Fault in CPU is Likely Due to Assembly Issue, not Bad CPU’s
April 18, 2023 15Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Methodology – Traced Clock, Data, and Power Paths on the Circuit Assembly
April 18, 2023 16Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Visible Artifacts and Associated Study
April 18, 2023 17
◊ Case Study Results: Glue on printed circuit board was contaminated by water
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Visible Artifacts and Associated Tests
April 18, 2023 18
Step 1: Photograph area of interest, where there is potential ionic contamination
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
April 18, 2023 19
Step 2: Use a scanning electron microscope (SEM) to identify sample of interest
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Visible Artifacts and Associated Tests
April 18, 2023 20
Step 3: Use energy dispersive x-ray spectroscopy (EDS) to plot the elements
Green arrows on the plot show the presence of salt - sodium chloride (NaCl) which indicates
fresh water was present in or near the glue
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Visible Artifacts and Associated Tests
SUCESSFUL EXAMPLE of Putting up the Walls in Formal Failure Analysis Study
From Legal Definitions - Categorized the Failure Legally: Most Likely a Manufacturing Defect – THIS WAS PROVEN
◊ Product Lifecycle in the Market – Product has been in Field Use for 3.5 Years, and CPU was Found to be Working Properly
◊ Outcome: Contaminated glue caused bridging between power and data lines - CPU was operating normally, but assembly defect caused intermittent data clocking errors
April 18, 2023 21Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Categorization of Failures: Overview and Basic Concepts
1. Definitions- Categorize the Failure First, if Possible: Legal Framework
2. FA Tips and Techniques: Put up Walls!3. Business Considerations
a. Product Lifecycle to Help Clarify Remediesb. Artifacts of Catastrophic Failures- Business
and Human Factors Losses
April 18, 2023 22Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
3. Business Considerations
April 18, 2023Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Product Lifecycle
24April 18, 2023Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Product Lifecycle Considerations for FA
1. Introduction: Not well-known across a wide variety of field conditions
2. Growth: May have several revisions in the field, may have deviated from regulatory compliance bill of materials
3. Maturity: Most likely lifecycle stage for Manufacturing Defects
4. Decline: The least amount of Engineering is dedicated, but more component issues
April 18, 2023 25Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Artifacts of Catastrophic Events
26April 18, 2023
◊ Case Study: Test engineer for semiconductor company sent email to another engineer that was part of Discovery, “I don’t know why we bother to test and grade these processors- we know we are going to just sell them all anyway.”
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Artifacts of Catastrophic Events
27April 18, 2023
◊ Moral declined when the failures were mentioned by brand name in the news.
◊ Then the team became emotional - attention to detail declined, causing more sub-standard products to slip through the QA final checks, then more returns from customers.
◊ Downward spiral, company’s revenue plunged for 2 years due to one bad batch of approximately 50,000 units that were sold without internal communication that they may be sub-standard. People quit.
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Artifacts of Catastrophic Events
28April 18, 2023
“The San Jose, California - based company's fourth-quarter loss was $22.7 million,
or $0.18 per share, compared to net profit of $27.2 million
or $0.16 per share last year.”
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
April 18, 2023
Thank you!
Categorization of Failures © Case Forensics 2014 – 2015, All Rights Reserved
Karen Rayment, MSEE, MBA, P.E., CFEI, PMP
Mobile: 510-775-3394
Krayment@CASEForensics.com
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