Presentation given at University of Arizona's annual reliability management conference.

1. Reliability Integration
Across the Product Life Cycle
Mike Silverman
Fred Schenkelberg
from
Ops A La Carte
www.opsalacarte.com
(408) 472-3889

2. Introduction
♦ “Reliability? Oh, that’s 50,000 hour MTBF!”
♦ “We design for a 5 year life.”
♦ “Every project passes HALT, no problem.”
A successful product reliability program is the
collection of goals, plans, tools, and skills focused
on the cost-effective and timely creation of products
that meet business objectives.

3. Agenda
♦ Introduction and Agenda
♦ Overview
♦ Reliability Goals
♦ Reliability Plan
♦ Reliability Execution
 FMEA and HALT
 Prediction and RDT/ALT
♦ Integration
♦ Wrap-up

4. Overview
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review

5. Overview
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review

6. Overview
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review

7. Overview
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review

8. Vocabulary
♦ Reliability
♦ Goal
♦ Plan
♦ FMEA
♦ HALT
♦ Prediction
♦ RDT
♦ ALT

9. Reliability Goal
1. Function
2. Probability
3. Duration
4. Environment
5. Customer Expectation
♦ Example: Our Power Supply will provide 5V with
a 90% reliability at 2 years in a home and office
environment.

10. Reliability Goal – How?
♦ Business objectives
♦ Warranty period
♦ Useful or expected functional life
♦ What is it supposed to do?
♦ Where and under what conditions?
♦ Estimated cost of product failure

11. Reliability Plan
♦ Goals, apportionment and metrics
♦ Selected tools for discovery
♦ Selected tools for analysis
♦ Selected tools for verification
♦ Procurement activities and critical parts
♦ Field service, maintenance, call centers

12. Reliability Plan
Engineering
Review
Determine Reliability
Targets
Initial Design
FMEA
Apportion Target &
Determine Gaps
Initial Design
(Prototype #1)
Subsystem ALTs HALT Competitive Competitive
& drop testing HALT Teardown
Improve Design
(Prototype #2)
Revise Apportion Update DOE Derating HALT
Targets and Gaps FMEA (if needed) Analysis
Improve Design
(Prototype #3 or
Production)
HALT Benchtop Identity CTQ
Lifecycle testing
Final System Establish
Reliability Control Plans
Reliability Analysis
Demonstration
Review
Results
Monitor
Metrics
Product
Launch Monitor CTQ
parameters

13. Reliability Execution
♦ Two distinct reliability schools
Measurement techniques
• Prediction
• RDT and ALT
Improvement techniques
• FMEA
• HALT

14. Reliability Execution
♦ Which should we use?
 Both, of course... but how do we integrate them
together?
FMEA Prediction
HALT RDT/ALT

15. Reliability Measurement
Techniques
♦ Prediction in Design Phase
♦ RDT in Prototype Phase
Prediction
RDT/ALT

16. Reliability Prediction
♦ Reliability Prediction Definition:
 A method of calculating the reliability of a product or
piece of a product from the bottom up by assigning a
failure rate to each individual component and then
summing all of the failure rates.

17. Reliability Prediction
♦ Reliability Predictions are used to:
 help calculate spares
 provide input to system-level reliability models
 assist in deciding which product to purchase
 drive design trade-off studies
 set achievable in-service performance standards
 help set test parameters for RDTs/ALTs

18. Reliability Prediction
♦ Limitations of a Prediction
 Predictions have inaccuracies due to:
• Data is from outdated standards
• Data is from different environments
• Data is from different applications
• Data is from unclean field data
• Technology is too new – no good models
 So what can we do?

19. Reliability Prediction
♦ Getting Around Prediction Limitations
 We use relative failure rate values rather than absolute
values and feed to a FMEA.
 We fill in gaps of inaccuracy with RDTs and ALTs.

20. Prediction Integrated with
FMEA
♦ Use results of Prediction for a FMEA
 In a FMEA, we are looking for high risk areas. To quantify
these risks, we need to assess the probability of the risk
occurring.
 Predictions can supply this probability.
 Usually, a probability relative to other risks is all that is
necessary, and a prediction is good for this.

21. Prediction Integrated with
RDT/ALT
♦ Use results of Prediction to plan an RDT/ALT
 Predictions will identify where a product is vulnerable to
help decide which RDT/ALT to run.
 Predictions can give you sensitivity of components to
thermal and electrical stress – key accelerants in the
RDT/ALT models.
 Predictions can help determine stress limits of
components when choosing accelerated stress levels for a
test.

22. Reliability Demonstration
Test (RDT)
♦ RDT: Definition
 A sample of units are tested to validate reliability
requirements.
 The test is usually performed at accelerated stresses to
compress time. The accelerated stresses can be
environmental, electrical, or mechanical.

23. Accelerated Life Test (ALT)
♦ ALT: Similar to RDT but also used:
 to characterize dominant failure mechanisms, often due to
wearout.
 usually at the assembly level rather than system level to
target specific areas of design.

24. RDT and ALT Parameters
♦ In order to set up an ALT, we must know (or
derive) several different parameters:
 Length of test
 Number of samples
 Goal of test
 Confidence desired
 Accuracy desired
 Cost
 Acceleration Factor
• Field Environment
• Test Environment
• Acceleration Factor Calculation
 Slope of Weibull Distribution (Beta factor)

25. RDT and ALT Parameters
♦ Keys to a Good RDT/ALT
 Accelerants must be valid
 Acceleration factors must be measurable
 Failure region must be well understood
• (infant mortality, steady state, wearout)
Note that the lead-free transition will change all our old
acceleration models.

26. RDT and ALT Parameters
♦ If we don’t have a good formula for acceleration
factor, we can determine through experimentation.
♦ When wearout is a dominant failure mode, we
cannot substitute units for time.
♦ If we cannot find environmental or electrical
accelerants, we can resort to duty cycle
acceleration.

27. Reliability Improvement
Techniques
♦ FMEA in the Design Phase
♦ HALT in the Prototype Phase
FMEA
HALT

28. Failure Modes Effects Analysis
(FMEA)
♦ FMEA is a systematic technique to analyze a
system for all potential failure modes.
♦ FMEA’s are used to identify highest risk items and
mitigate them to reduce overall product risk.

29. FMEA Integrated with HALT
♦ When planning a HALT, FMEA’s can be used for:
 identifying failure modes that HALT is likely to uncover.
 identifying failure modes that require extra planning to
find.
 identifying non-relevant failure modes.
 Identifying wearout mechanisms that HALT will not be
able to find.
 helping to decide on the number of samples.

30. Highly Accelerated Life Testing
(HALT)
♦ HALT is a method of applying progressively higher
levels of environmental, electrical, and mechanical
stresses to a product to the point of failure in order
to assess and improve design robustness and
margin above its intended operation.

31. Highly Accelerated Life Testing
(HALT)
♦ HALT is used to:
 Quickly discover design issues.
 Evaluate and improve design margins.
 Release mature product at market release.
 Reduce development time and cost.
 Evaluate cost reductions made to product.

32. Highly Accelerated Life Testing
(HALT)
HALT, How It Works
Fa
ilu
sse
ea
se)
re
(in r
cr
St
is
Im
s
pr
ov aly
An
e

33. Highly Accelerated Life Testing
(HALT)
Lower Lower Upper Upper
Destruct Oper. Product Oper. Destruct
Limit Limit Operational Limit Limit
Specs
Destruct
Margin
Operating
Margin
Stress

34. Highly Accelerated Life Testing
(HALT)
HALT, Why It Works
Classic S-N Diagram
(stress vs. number of cycles)
S2 S0= Normal Stress conditions
N0= Projected Normal Life
Stress S1
S0
N2 N1 N0
Number of Cycles

35. Highly Accelerated Life Testing
(HALT)
Limitations of HALT
Classic S-N Diagram
(stress vs. number of cycles)
Point at which failures become non-relevant
S2 S0= Normal Stress conditions
N0= Projected Normal Life
Stress S1
S0
N2 N1 N0
Number of Cycles

36. Reliability Integration
Between HALT and RDT/ALT
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review

37. Reliability Integration
Between HALT and RDT/ALT
♦ Often times we will run a product through HALT and then run
the subassemblies through ALT that were not good
candidates for HALT.
HALT on System ALT on System Fan

38. Reliability Integration
Between HALT and RDT/ALT
♦ And at other times, we may develop an RDT based on HALT
limits, using the same accelerants but lowering the
acceleration factors to measurable levels.
HALT on System RDT on System

39. Reliability Integration Back to
Goals
Goal
Plan
FMEA Prediction
HALT RDT/ALT
Verification
Review

40. Reliability Integration Back to
Goals
♦ Field Data will tell us:
 if our goals were accurate.
 If our plan was complete.
 If our individual tools were effective.
♦ If not, make adjustments for next program.

41. Wrap Up
♦ A successful product reliability program is the
collection of goals, plans, tools, and skills focused
on the cost-effective and timely creation of
products that meet business objectives.
♦ To minimize total Life Cycle Costs, we:
 create clear goals.
 choose the best tools.
 properly integrate the tools forwards and back.

42. Questions
WHAT ARE YOUR QUESTIONS?

43. Presenter’s Biographical
Sketch
♦ Fred Schenkelberg, (408) 710-8248, fms@opsalacarte.com
♦ Fred Schenkelberg is a Senior Reliability Engineering Consultant at Ops A La Carte. He is
currently working with clients using reliability assessments as a starting point to develop and
execute detailed reliability plans and programs. Also, he exercises his reliability engineering
and statistical knowledge to design and conduct accelerated life tests.
♦ Fred joined HP in February 1996 in Vancouver, WA. He joined ESTC, Palo Alto, CA., in
January 1998 and co-founded the HP Product Reliability Team. He was responsible for the
community building, consulting and training aspects of the Product Reliability Program. He
was also responsible for research and development on selected product reliability
management topics.
♦ Prior to joining ESTC, he worked as a design for manufacturing engineer on DeskJet
printers. Before HP he worked with Raychem Corporation in various positions, including
research and development of accelerated life testing of polymer based heating cables.
♦ He has a Bachelors of Science in Physics from the United States Military Academy and a
Masters of Science in Statistics from Stanford University. Fred is an active member of the
RAMS Management Committee and currently the IEEE Reliability Society Santa Clara Valley
Chapter Vice President.

44. Presenter’s Biographical
Sketch
♦ Mike Silverman, (408) 472-3889, mikes@opsalacarte.com
♦ Mike is founder and managing partner at Ops A La Carte, a Professional Business Operations
Company that offers a broad array of expert services in support of new product development and
production initiatives. The primary set of services currently being offered are in the area of reliability.
Through Ops A La Carte, Mike has had extensive experience as a consultant to high-tech
companies, and has consulted for over 200 companies including Cisco, Ciena, Apple, Siemens,
Intuitive Surgical, Abbott Labs, and Applied Materials. He has consulted in a variety of different
industries including telecommunications, networking, medical, semiconductor, semiconductor
equipment, consumer electronics, and defense electronics.
♦ Mike has 20 years of reliability, quality, and compliance experience, the majority in start-up
companies. He is also an expert in accelerated reliability techniques, including HALT and HASS. He
set up and ran an accelerated reliability test lab for 5 years, testing over 300 products for 100
companies in 40 different industries. Mike has authored and published 7 papers on reliability
techniques and has presented these around the world including China, Germany, and Canada. He
has also developed and currently teaches 8 courses on reliability techniques.
♦ Mike has a BS degree in Electrical and Computer Engineering from the University of Colorado at
Boulder, and is both a Certified Reliability Engineer and a course instructor through the American
Society for Quality (ASQ), IEEE, Effective Training Associates, and Hobbs Engineering. Mike is a
member of ASQ, IEEE, SME, ASME, PATCA, and IEEE Consulting Society and currently the IEEE
Reliability Society Santa Clara Valley Chapter President.

45. Thank you
© 2005