3. Tutorial Objectives
To outline the key traits for the effective
management of a reliability program.
To make you think about how to implement
reliability engineering within an organization.
6. Additional Reading
Practical Reliability Engineering, 4th Edition,
Patrick D. T. O’Connor, 2002
Improving Product Reliability: Strategies and
Implementation, Mark A. Levin and Ted T.
Kalal, 2003
Quality if Free: The Art of Making Quality
Certain, Philip B. Crosby, 1979
Design Paradigms: Case Histories of Error
and Judgment in Engineering, Henry Petroski,
1994
7. HP’s Design for Reliability Story
Which activities have impact?
9. The Situation
"Based on an in-depth study of HP's most
successful divisions, we discovered that as
much as 25% of our manufacturing assets
were tied up in reacting to quality problems!
"Clearly, a bold approach was needed to con-
vince people that a problem existed and to fully
engage the entire organization in solving it."
10. The 10X Challenge
"The proper place to start, we concluded,
was with a startling goal - one that would
get attention. The goal we chose was a
tenfold reduction in the failure rates of
our products during the 1980's."
John
Young
HP CEO
11. Dick Moss retired from HP in February
1999, as the Corporate Product
Reliability Manager and winner of the
CEO’s Customer Satisfaction Award.
He worked at HP 39 years, the first 15
in new product development (R&D),
and the last 24 in hardware quality &
reliability. During that time, he
presented more than 700 technical
seminars to over 35,000 HP employees
worldwide. He wrote or edited parts of
4 books and published numerous
papers. He holds a BSEE from
Princeton and an MSEE from Stanford,
and has one patent.
12. The 10X Challenge Results
FAILURE RATE
Actual 10X Goal
(Normalized)
1.2
1.0
0.8
0.6
0.4
0.2
0.126 ACTUAL (8X)
0.100 GOAL (10X)
0.0
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
FISCAL YEAR
13. Warranty Savings During 10X
(ACTUAL vs PROJECTED @ 1980 RATE)
ACTUAL 1980 RATE
$300M
$200M
ANNUAL $808 MILLION
EXPENSE 10 YR SAVINGS
PROJECTED COST
$100M
ACTUAL WTY COST
0
FY80 FY81 FY82 FY83 FY84 FY85 FY86 FY87 FY88 FY89 FY90
FISCAL YEAR
14. Design for Reliability
HOW'D WE DO THAT?
Commitment
Management Leadership & Involvement
Lengthen Warranty Period
Find & Share Best Practices
16. DFR Survey
SURVEY CHECKLIST
Scoring: 4 = 100%, top priority Engineering:
3 = >75, use expected Documented design cycle
2 = 25 - 75%, variable use Reliability goal budgeting
1 = <25%, occasional use Priority of reliability improvement
0 = not done or discontinued DFR training programs
Preferred technology program
Management:
Component qualification testing
Goal setting for division
OEM selection & qualif. Testing
Priority of Quality & Reliab.
Physical failure analysis
Mgmnt attention & follow up
Root cause analysis
Manufacturing: Statistical engineering experiments
Design for Manufacturability Design & stress derating rules
Priority of Q & R goals Design reviews & checking
Ownership of Q & R goals Failure rate estimation
Quality training programs Thermal design & measurements
SPC & SQC use Worst case analysis
Internal process audits Failure Modes & Effects Analysis
Supplier process audits Environmental (margin) testing
Incoming inspection Highly Accel. Stress Testing
Product burn-in Design defect tracking
Defect Tracking Lessons-learned database
Corrective action
17. results
widespread use
environmental test
manual
product lifecycle
range of use
module goal setting
derating rules
limited use
DFR training
physics of failure
analysis
18. findings
ODM concerns
how to convey needs
and get reliable products?
time to market priority
urgent versus important
management structures
many ways to organize roles
mature products & scores
when only select tools apply
19. observations
best practices worst practices
goal setting repair & warranty
prediction invisible
statistics lessons learned capture
golden nuggets single owner of product
first look process reliability
multiple defect tracking
systems
22. Reliability Definition
Reliability is often considered quality over
time
Reliability is the probability of a product
performing its intended function over its
specified period of usage, and under
specified operating conditions, in a
manner that meets or exceeds customer
expectations.
23. Reliability Goals & Metrics Summary
Reliability Goals & Metrics tie together all
stages of the product life cycle. Well
crafted goals provide the target for the
business to achieve, they set the
direction.
Metrics provide the milestones, the “are
we there, yet”, the feedback all elements
of the organization needs to stay on track
toward the goals.
24. Reliability Goals & Metrics Summary
A reliability goal includes each of the four
elements of the reliability definition.
o Intended function
o Environment (including use profile)
o Duration
o Probability of success
o [Customer expectations]
25. Reliability Goals & Metrics Summary
A reliability metric is often something that
organization can measure on a relatively short
periodic basis.
o Predicted failure rate (during design phase)
o Field failure rate
o Warranty
o Actual field return rate
o Dead on Arrival rate
26. Reliability Goal-Setting
Reliability Goals can be derived from
o Customer-specified or implied requirements
o Internally-specified or self-imposed requirements
(usually based on trying to be better than previous
products)
o Benchmarking against competition
27. Example Exercise
Elements of Product Requirements Document
Take notes to build a reliability goal statement
28. PRD Scope
This document defines the product specification for the
Device A (Dev A). This specification includes a
description of all electrical, mechanical, and
functional aspects of the Dev A. It is intended to
define the characteristics of the Dev A, but is not
intended to describe a specific design
implementation, which is covered in other
documents. Unless otherwise specified, the
tolerance of the nominal values specified herein will
be taken as ± 20% at an ambient temperature of
25° C.
Dev A provides demand-only flow regulation in order to
conserve gas.
29. PRD Background
The device includes a built in regulator, valve, control
circuitry, and enclosure. The device will be designed
to attach to a standard compressed gas cylinder.
The industrial design of the device allows the user a
simple method of attachment to the cylinder and easy
access to all controls, batteries, and outlet port.
A high-valuation, portable, 2 year life, dependable
product will be targeted, while minimizing cost of
goods to permit market flexibility.
30. PRD Reliability Section
Warranty Period
The Warranty period will be decided by Marketing prior
to release. The MRD currently states a 1 year
warranty, however, for design purposes a two year
warranty period shall be assumed.(PRD074)
Reliability Over Warranty Period
The project goal is less than 2% at the end of first years
production.
Maintainability
The Dev A is intended to be serviced and repaired by
Company A authorized service centers or authorized
health care providers.
31. PRD Reliability Section
Useful Life
The useful design life of the Dev A shall be
6,000 hours based on 4 years at 4 hours use
per day.(PRD077)
32. PRD Environment Section
Operating Environment
These devices shall meet all performance
specifications defined herein while subject to
the following environmental conditions
unless otherwise specified:(PRD078)
Temperature: 5 to 40° C
Relative Humidity: 15 to 95% non-condensing
Atmospheric Pressure: 76.7 to 102 kPa
DC Supply Voltage: 4.5 to 6.5 VDC
33. PRD Environment Section
Storage Environment
These devices shall perform to all specifications
after one hour at operating environment
conditions after storage at the following
environmental conditions :(PRD079)
Temperature: -20 to 60 ° C
Relative Humidity: 15 to 95% non-condensing
The Dev A and all package contents shall be
stored in a sealed plastic bag away from oil
and grease contaminates.(PRD080)
34. Goal Statement exercise
In groups of two or three draft a reliability goal
Note the missing information and draft
questions to get the missing information
This is a brand new product with no field
history – how would you apportion the system
goal to the various subsystems?
(regulator, valve, control circuitry, and enclosure)
35. Reliability Goals & Metrics Summary
A reliability metric is often something that
organization can measure on a relatively
short, periodic basis:
o Predicted failure rate (during design phase)
o Field failure rate
o Warranty
o Actual field return rate
o Dead on Arrival rate
(v5)
36. Fully-Stated Reliability Goals
System goal at multiple points
o Supporting metrics during development and field
o Apportionment to appropriate level
Provide connections to overall business plan,
contracts, customer expectations, and include
any assumptions concerning financials
Benefit: clear target for development, vendor
and production teams.
(v5)
37. Reliability Goal
−t
Let’s say we expect a few
failures in one year.
Less than 2%
R(t ) = e θ
ln(.98) = −8760 / θ
Laboratory environ.
XYZ function
XYZ function for one year with
Assuming constant failure
rate 98% reliability in the lab.
(MTBF is 433,605 hrs.)
(v5)
38. Other Points in Time
Also consider other business relevant points in
time
Infant mortality, out of box type failures
o Shipping damage
o Component defects, manufacturing defects
Wear out related failures
o Bearings, connectors, solder joints, e-caps
(v5)
39. Break Down Overall Goal
Let’s look at example
A computer with a one year warranty and the
business model requires less than 5% failures
within the first year.
o A desktop business computer in office environment
with 95% reliability at one year.
(v5)
40. Break Down the Goal, (continued)
For simplicity consider five major elements
of the computer
o CPU/motherboard
o Hard Disk Drive
o Power Supply
o Monitor
o Bios, firmware
For starters, let’s give each sub-system the
same goal
(v5)
41. Apportionment of Goals
Computer
R = 0.95
CPU HDD P/S Monitor Bios
R = 0.99 R = 0.99 R = 0.99 R = 0.99 R = 0.99
Assuming failures within each sub-system are independent, the simple
multiplication of the reliabilities should result in meeting the system goal
0.99 * 0.99 * 0.99 * 0.99 * 0.99 = 0.95
Given no history or vendor data – this is just a starting point.
(v5)
42. Estimate Reliability
The next step is to determine the sub-system
reliability.
o Historical data from similar products
o Reliability estimates/test data by vendors
o In house reliability testing
At first estimates are crude, refine as needed
to make good decisions.
(v5)
43. Apportionment of Goals
Computer
R = 0.95
Goals
CPU HDD P/S Monitor Bios
R = 0.99 R = 0.99 R = 0.99 R = 0.99 R = 0.99
Estimates
CPU HDD P/S Monitor Bios
R = 0.96 R = 0.98 R = 0.999 R = 0.99 R = 0.999
First pass estimates do not meet system goal. Now what?
(v5)
44. Resolving the Gap
CPU goal 99% est. 96% Use the simple reliability model
to determine if reliability
improvements will impact the
Largest gap, lowest estimate system reliability. i.e. changing
the bios reliability form 99.9% to
First, will the known issues 99.99% will not significantly
bridge the difference? alter the system reliability result.
Invest in improvements that will
In not enough, then use FMEA
and HALT to populate Pareto of impact the system reliability.
what to fix
Third, validate improvements
(v5)
45. Resolving the Gap, (continued)
When the relationship of the
HDD goal 0.99 est. 0.98
failure mode and either design
or environmental conditions
Small gap, clear path to resolve exist we do not need FMEA or
HALT – go straight to design
HDD reliability and operating improvements.
temperature are related.
Lowering the internal Use ALT to validate the model
temperature the HDD and/or design improvements.
experiences will improve
performance.
(v5)
46. Resolving the Gap, (continued)
For any subsystem that exceeds
P/S goal 0.99 est. 0.999
the reliability goal, explore potential
cost savings by reducing the
Estimate over the goal reliability performance.
This is only done when there is
Further improvement not cost accurate reliability estimates and
effective given minimal impact significant cost savings.
to system reliability.
Possible to reduce reliability
(select less expensive model)
and use savings to improve
CPU/motherboard.
(v5)
47. Progression of Estimates
Uppe
r Con
fide nce in
Estim
ate
Actual Field
Data
at a Dt s e T
at a Dr odne V
te
stima
e in E
fi de nc
Con
e n gn El aiti nI
er
L ow
(v5)
i
48. Microsoft Model
Proposed Model:
Get feedback to the design and
manufacturing team that permits visibility of
the reliability gap. Permit comparison to goal.
Microsoft Model:
Not estimating or measuring the reliability
during design is something I call the Microsoft
model. Just ship it, the customers will tell you
what needs improvement.
Don’t try the Microsoft Model!
(it works for them but probably won’t work for you)
(v5)
49. Reliability Goals & Metrics Summary
A reliability goal includes each of the four
elements of the reliability definition.
o Intended function
o Environment (including use profile)
o Duration
o Probability of success
o [Customer expectations]
51. Build, Test, Fix
In any design there are a finite number of
flaws.
If we find them, we can remove the flaw.
Rapid prototyping
HALT
Large field trials or ‘beta’ testing
Reliability growth modeling
52. Analytical Approach
Develop goals
Model expected failure mechanisms
Conduct accelerated life tests
Conduct reliability demonstration tests
Routinely update system level model
Balance of simulation/testing to increase
ability of reliability model to predict field
performance.
53. Issues with each approach
Build, Test, Fix Analytical
Uncertain if design is Fix mostly known flaws
good enough ALT’s take too long
Limited prototypes RDT’s take even longer
means limited flaws Models have large
discovered uncertainty with new
Unable to plan for
technology and
warranty or field service environments
54. Balanced approach
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review
55. Balanced approach
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review
56. Balanced approach
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review
57. Balanced approach
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review
58. Reliability Planning
Selecting the minimum set of tools to
achieve the reliability goals
59. Planning Introduction
Mil Hdbk 785 task 1
“The purpose of this task is to develop a
reliability program which identifies, and ties
together, all program management tasks
required to accomplish program
requirements.”
60. Fully Stated Reliability Goals
System goal at multiple points
o Supporting metrics during development and field
o Apportionment to appropriate level
Provide connections to overall business plan,
contracts, customer expectations, and include
any assumptions concerning financials
Benefit: clear target for development, vendor
and production teams.
61. Medicine
"The abdomen, the chest, and the brain will be
forever shut from the intrusion of the wise and
humane surgeon"
Sir John Erichsen
leading British surgeon, 1837
62. Gap Analysis
Estimate/review current reliability of system
against the next project goal
The difference is the gap to close
That gap is what the plan needs to bridge
63. Path to close gap
This is the ‘art’ of our profession and each
project needs a unique solution.
Just because the plan succeeded for the last
project, it may not work for the current one
o Timelines change
o Goals and risks change
o Business objectives and customer expectations
change
o The organization has grown/lost capabilities
64. If, small gap and clear Parato
Then,
Select issues on Parato from past products
that have the easiest cost, timeline, risk.
Engineering doesn’t need HALT or FMEA to
identify or prioritize issues to resolve
Assumes a system/sub-system reliability
model, even as simple as Parato based on
failure rates.
Engineers may need ALT to verify solution
assumptions
65. If, large gap and clear Parato
Then,
Same as small gap, generally
Early step is to estimate ability to close gap
with reasonable business risk
If there is doubt on validity of issues to
resolve, consider HALT to uncover possible
new issues
66. If, new features, new market
Then,
Increase use of HALT, including on
competitor’s products if possible
Increase use of environmental testing (HALT
if able to afford samples and testing
facilitates). Find margins related to new
market environment.
Use reliability growth modeling to determine if
plan of record is able to meet goals
67. If, reliant on vendor’s failure
analysis
Then,
Consider building internal or third party failure
analysis and component expertise
Accelerate time to detection of vendor issues
68. If, (what is your situation)
When starting a project, consider the goals,
constraints, etc. and look at the entire
horizontal process.
Then,
Let’s find a few options to consider
69. Exercise
Identify a circumstance and an approach to
building the reliability plan.
What will be the biggest challenges to
implementing the plan?
Separate from the plan, what will you do as
the reliability engineer do to overcome the
obstacles?
70. Close on Planning Discussion
Introduction to Planning
Fully stated reliability goals
Constraints
o Timeline
o Prototype samples
o Capabilities (skills and maturity)
Current state and gap to goal
Paths to close the gap
o Investments
o Dual paths
o Tolerance for risk
71. Television
"People will soon get tired of staring at a
plywood box every night."
Darryl F. Zanuck
Twentieth Century-Fox, 1946
74. Introduction
Many (most, all?) products have a warranty
Examples of how to use this information in
your reliability engineering work
75. Electric Light
“Good enough for our transatlantic friends, but
unworthy of the attention of practical or
scientific men.”
British Parliament report on Edison’s work
1878
76. Overview
Warranty as a percentage of revenue.
Warranty as a cost per unit.
Who owns warranty?
How much warranty expense is right?
What is the right investment to reduce
warranty?
78. Computers
“There is no reason for any individual to have a
computer in their home.”
Ken Olson
Digital Equipment Corp. 1977
79. Reliability Specifications
Example
Given two fan datasheets
Fan A has a mean time to fail of 4645 hours
Fan B has a mean time to fail of 300 hours
Both same price, etc.
Choose one to maximize reliability
at 100 hours
80. Reliability Specifications
Example
Consulting an internal fan expert, you are
advised to get more information
Fan A has a Weibull time to fail shape
parameter of 0.8
Fan B has a Weibull time to fail shape
parameter of 3.0
1
µ = θΓ1 +
β
81. Reliability Specifications
Example
Fan A has a scale parameter of 4100 hours
Fan B has a scale parameter of 336 hours
Use the Weibull Reliability function
−( t /θ ) β
R (t ) = e
Fan A reliability at 100 hours is 0.95
Fan B reliability at 100 hours is 0.974
82. Reliability Specifications
Example
Given two fan datasheets
Fan A has a mean time to fail of 4645 hours
Fan B has a mean time to fail of 300 hours
What about later, say 1000 hours?
Fan A reliability at 1000 hours is 0.723
Fan B reliability at 1000 hours is 3.5E-12
83. The Telephone
"That's an amazing invention, but who
would ever want to use one of them?"
Rutherford Hayes
U.S. President, 1876
84. The Cost Reduction Example
Given a FET that costs 10 cents, a new
procurement engineer finds a new FET
vendor that only charges 5 cents.
Switch?
What else to consider?
85. The Cost Reduction Example
Given a FET that costs 10 cents, a new
procurement engineer finds a new FET
vendor that only charges 5 cents.
$0.05 FET has MTBF of 50,000 hours
$0.10 FET has MTBF of 75,000 hours
1000 hours of operation
Shipping 1000 units
Cost to repair unit $250
86. The Cost Reduction Example
Total Cost of $0.10 FET
1000
−
R0.10 (1000 ) = e 75, 000
= 0.987
#Failed = (1-0.987) 1000units = 13.25
Cost of Repairs = 250*13 = $3250
Total Cost = $3250+0.10*1000 = $3350
87. The Cost Reduction Example
Total Cost of $0.05 FET
1000
−
R0.05 (1000 ) = e 50 , 000
= 0.98
#Failed = (1-0.98) 1000units = 20
Cost of Repairs = 250*20 = $5000
Total Cost = $5000+0.05*1000 = $5050
88. The Cost Reduction Example
Total Cost of $0.50 FET
1000
−
R0.50 (1000 ) = e 100 , 000
= 0.99
#Failed = (1-0.99) 1000units = 10
Cost of Repairs = 250*10 = $2500
Total Cost = $2500+0.50*1000 = $3000
89. The Cost Reduction Example
Result?
FET Repair Total
Cost Cost Cost
$0.10 $3250 $3350
75,000 hrs
$0.05 $5000 $5050
50,000 hrs
$0.50 $2500 $3000
100,000hrs
90. Aviation
"The popular mind often pictures gigantic flying
machines speeding across the Atlantic and
carrying innumerable passengers...it seems
safe to say that such ideas are wholly
visionary."
Wm. Henry Pickering
Harvard astronomer, 1908
91. Component Challenges
Cost driving manufacturing to low labor cost
areas of the world
Pb-free causing redesign/reformulation
Outsourced design and manufacturing
facilities gaining “commodity’ component
selection
Other than yield - who’s watching Quality,
Reliability and Warranty?
93. Component Challenges
Trust and verify solution
Build strong, technically verifiable, language
into purchase contracts
Check construction and formulation on
periodic basis
94. Nuclear Energy
"Nuclear powered vacuum cleaners will
probably be a reality within 10 years."
Alex Lewyt
vacuum cleaner manufacturer,1955
95. Where to Get More Information
Newsletter and seminars
http://Warrantyweek.com
“Warranty Cost: An Introduction”
http://quanterion.com/ReliabilityQues/V3N3.html
“Economics of Reliability,” Chapter 4 of
Handbook of Reliability Engineering and
Management, 2nd Ed by Ireson, Coombs and Moss.
99. Terms
Value
o An amount considered to be a suitable equivalent
for something else; a fair price or return for goods
or services
Value Add
o The return or result of individual, team or product
investment
Value Capture
o Value add documentation related directly to
merger
Warranty Reduction
o Lower failure rates leading to fewer claims
100. How is value requested?
Quarterly review: What have you done for me
lately?
Checkpoint meeting: Are we on track to meet
goals?
Budget: Which option provides best ROI?
Annual review: What is your impact?
102. Warranty – The Big Picture
”American manufacturers spent over $25 billion in
2004 honoring their product warranties, an increase
of 4.8% from the levels seen in 2003. However, an
incredible 63% of U.S.-based product manufacturers
actually saw a decrease in their claims rates as a
percentage of sales. Only 35% saw an increase and
2% saw no change, according to the latest statistics
compiled by Warranty Week.”
Eric Arnum, Warranty Week
www.warrantyweek.com, May 27th, 2005
104. VALUE ADDED/ROI
QUESTIONAIRE
Savings/Impact/Benefit
1. Risk / cost / warranty a. Has the work directly identified or mitigated a field related problem
reduction
b. If so estimate the probable cost of the field problem in $ (i.e. units
affected x repair cost)
c. Has the probability of field related problems been reduced?
d. If so give a guide by how much and the estimated cost of avoidance
(i.e. Estimate 1000 units per month failure at $50 each reduced by 5%)
e. Has work provided processes which will reduce the risk of field
failures in subsequent products?
2. TTM impact: a. Did work help you meet or beat your TTM goals?
b. Did work identify any problems which would have impacted your
TTM?
c. Has the use of tools/techniques identified issues which would of
impacted TTM?
d. If the above are applicable please identify type of problems and
estimate TTM impact in days/weeks/months
e. What is the estimated cost of a delay in TTM?
f. What is the opportunity in $ of additional income from an early
TTM?
105. VALUE ADDED/ROI
QUESTIONAIRE
Savings/Impact/Benefit
3. TT Volume impact: a. Did work help you accelerate or meet your Time to Volume
goals?
b. If applicable what is the estimated $ impact of avoiding the
TTV issues that were identified
4. Material costs: a. Did we avoid or save any direct product material or test
equipment costs?
b. If so please identify type and cost
5. TCE: a. Has the work contributed to the TCE of your product?
b. If so identify how? i.e. estimated number of customer calls
avoided
c. If you have a TCE cost model what is the estimated $ impact
of the identified improvement
6.Opportunity Cost a. If engineers from the business had been used to do this work
would they have not been able do other product related work. I.e.
delivered new functions?
7. Indirect Impact: a. What advantages did internal work provide over an external
consultancy? (i.e. time, cost, contractual issues, Intellectual
Property, response time)
106. “I fall back dazzled at beholding myself all rosy red,
At having, I myself, caused the sun to rise
Edmund Rostand (1868-1918)
107. VALUE ADDED/ROI
QUESTIONAIRE
Savings/Impact/Benefit
8. Engineering effort a. How long would it have taken your team to undertake the
saved: work provided. Take into account research time and whether you
had the skills available
b. If you did not have the skills available how many people
would have needed to be recruited to undertake the work?
c. How long would it take for these people to become
productive?
d. Estimate training cost associated with new personnel
9. Misc a. Please identify any other benefits or cost savings from using
our resources
108. “Gross national product measures neither the health of our children,
the quality of their education, nor the joy of their play
It measures neither the beauty of our poetry, nor the strength of our
marriages.
It is indifferent to the decency of our factories and the safety of our
streets alike.
It measures neither our wisdom nor our learning, neither our wit nor
our courage, neither our compassion or our devotion to country.
It measures everything in short, except that which makes life worth
living, and it can tell us everything about our country except those
things which make us proud to be part of it.”
Robert Kennedy
109. Your ‘value case’
Problem statement
Work done to solve problem
Value statement(s)
111. Maturity Matrix
Handout Matrix
Based on Quality Management Maturity Grid
from Quality is Free, c 1979 by Philip B.
Crosby
112. Measurement Categories
Management Understanding and Attitude
o Business objectives and language
o Attention and investments
Reliability Status
o Position and stature
o Location and influence
113. Measurement Categories
Problem Handling
o Proactive or Reactive
Cost of ‘Un’ Reliability
o Understanding and influence of metrics
o Local budget or total product cost
Feedback Process
o Predictions, reliability testing
o Failure analysis, time to detection
114. Measurement Categories
DFR program status
o Exists separately or integrated
o Template or customized
Summation of Reliability Posture
o How does the organization talk about reliability?
115. Stage I Uncertainty
Management – blame others
Status – hidden or doesn’t exist
Problems – may have good fire fighting
Cost – unknown and no influence
Feedback – customer returns & complaints
DFR – doesn’t exist even with designers
Summation – “Reliability must be ok, since
customer’s are buying our products.”
116. Stage II Awakening
Management – important w/o resources
Status – champion recognized
Problems – organized fire fighting
Cost – generally warranty only
Feedback – disorganized, antidotal
DFR – trying some tools
Summation – “We really should make more
reliable products.”
117. Stage III Enlightenment
Management – Support and encouragement
Status – Senior staff influence
Problems – Systematic and reactive
Cost – Starting to track cost of un-reliability
Feedback – ALT and modeling, root cause
DFR – program of reliability activities
Summation – “We can see how these tools
help our product’s field performance.”
118. Stage IV Wisdom
Management – Personally involved, leading
Status – Senior manager, major role
Problems – found and resolved quickly
Cost – understanding of major drivers
Feedback – selective testing in risk areas
DFR – Part of products get designed
Summation – “We avoid most field reliability
issues”
119. Stage V Certainty
Management – Considered core capability
Status – thought leader in company
Problems – Only a few issue, & expected
Cost – Accurate and decreasing
Feedback – Testing & field support models
DFR – Normal part of company business
Summation – “We do get surprised by the few
field failures that occur.”
120. Why do we need to know Maturity?
Recommendations need to match the
organizations capabilities
From current state build path toward the right
one step at a time
Value proposition for changes address
management approach to reliability
121. How to determine maturity?
Self assessment
o Small team from across organization
o Each marks blocks that describe their maturity
o Team determine Stage description by consensus
Observation from within an organization
o As an individual trying to position changes
o Informally conduct self assessment
122. How to determine maturity?
Assessment Interviews
o Conduct interviews to understand current reliability
activities
o Review and summarize interviews
o Interpret results onto maturity matrix
129. manufacturing survey topics
Manufacturing:
Design for manufacturability (DFM)
Priority of Q&R vs schedule & cost
Quality training programs
Statistical Process Control (SPC/SQC)
Total Quality Management (TQM)
HP process audits (written reports)
Vendor (& OEM) process audits, TQRDCE
Incoming inspection/sampling
Component burn-in
Assembly-level environmental stress screening (ESS)
Product-level environmental stress screening (ESS)
Defect Detection & Tracking (DD&T)
Corrective Action Reports
Ownership of quality & reliability goals
130. Aircraft Company Example
AC, Inc. a private jet manufacturer, develops,
manufactures, sells and provides support for
aircraft, throughout the intended life cycle.
The product design process is dominated by
the ability to meet FAA certification
requirements. This product is high cost and
very low volume.
Handout, AC, Inc. Survey Summary
Determine maturity stage and make
recommendations
131. AC, Inc. key points
MTBF metrics
Excellent field data
Very limited sample sizes
Reactive mode to improvement activities
132. AC, Inc. Recommendations
Use Reliability rather than MTBUR. Establish fully
stated reliability goal in terms of the probability of
components and aircraft successfully performing as
expected under stated conditions for two or more
defined time periods. Reliability is a metric that does
not have a dependence on a particular lifetime
distribution and is intuitively interpreted by engineers
correctly. Using multiple time marks, it promotes the
use of lifetime distributions rather than single
parameter descriptions. Once engineers are using
lifetime distributions, calculating confidence intervals
is a natural extension.
133. AC, Inc. Recommendations
Build and support an aircraft reliability model. Use the historical
data, lifetime distributions (not MTBUR), RBD (reliability block
diagramming) and simple mathematics to quickly create a basic
reliability model. An extension of the model would be to
incorporate the various environmental factors, flight profiles, and
the influence of other relevant variables on failure rates. For
example, some systems experience damaging stress during
takeoffs and landings, others only while in flight, some only
when landing in high temperature and humidity climates. Ideally
for each component the model would incorporate historical field
history along with environmental and component data. Even a
very simple model that enables the design and procurement
teams to evaluate options is well worth the effort to build and
support. Most importantly a reliability model provides feedback
very quickly to the design team during the design process.
134. AC, Inc. Recommendations
Handout, AC, Inc. recommendations and
matrix results
Basic idea is to make the reliability engineer
more valuable to the design team by building
an aircraft reliability model.
Value proposition: better design tradeoffs that
include reliability.