2. ASQ Reliability Division
English Webinar Series
One of the monthly webinars
on topics of interest to
reliability engineers.
To view recorded webinar (available to ASQ Reliability
Division members only) visit asq.org/reliability
To sign up for the free, and available to anyone,
live webinars visit reliabilitycalendar.org/webinars
http://reliabilitycalendar.org/webina
rs/english/
3. Mike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 3 September 12, 2013ASTR 2013 Oct 9-11, San Diego
Accelerated Stress Testing and Reliability Workshop
October 9-11, 2013 San Diego, CA
Accelerating Reliability into the 21st
Century
Keynote Presenter Day 1: Vice Admiral Walter Massenburg
Keynote Presenter Day 2: Alain Bensoussan, Thales Avionics
Accelerating Reliability into the 21st
Century
Keynote Presenter Day 1: Vice Admiral Walter Massenburg
Keynote Presenter Day 2: Alain Bensoussan, Thales Avionics
CALL FOR PRESENTATIONS: We are now Accepting Abstracts.
Email to: don.gerstle@gmail.com.
Guidelines on website www.ieee-astr.org
For more details, click here to join our LinkedIn Group:
IEEE/CPMT Workshop on Accelerated Stress Testing and Reliability
4. Mike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 4 September 12, 2013ASTR 2013 Oct 9-11, San Diego
This is the 4th of a series of four webinars being
put on by Ops A La Carte, ASTR, and ASQ
Reliability Division
Each webinar will also be presented as a full 2 hour
tutorial at our ASTR Workshop Oct 9-11th
, San
Diego.
Abstracts for presentations are due Apr 30.
www.ieee-astr.org
5. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 5 September 12, 2013
♦ Introduction 5 min
♦ Accelerated Reliability Growth Testing 45 min
♦ Questions 10 min
Agenda
6. Mike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 6 September 12, 2013ASTR 2013 Oct 9-11, San Diego
40 Years of HALT:
What Have We Learned?
By
Mike Silverman, CRE
Managing Partner
Ops A La Carte
mikes@opsalacarte.com
www.opsalacarte.com
7. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 7 September 12, 2013
INTRODUCTION
HALT began 40 years ago with a simple idea of testing
beyond specifications in order to better understand
design margins.
Over the past 40 years, thousands of engineers around
the world have been exposed to the concepts of HALT
and have tried the techniques.
What have we learned in the past 40 Years?
8. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 8 September 12, 2013
INTRODUCTION
In this seminar, we will cover the following areas:
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in HALT methodology
5) What % of companies are doing HALT
6) What lies in the future for HALT
9. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 9 September 12, 2013
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in equipment
5) What % of companies are doing HALT
6) What lies in the future for HALT
10. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 10 September 12, 2013
WHAT IS HALT?
HALT: Done to ruggedize the product and obtain
large margins over the expected in-use conditions. Uses
all stresses which can cause relevant failures. Stresses
are not limited to field levels or stresses.
- “Accelerated Reliability Engineering: HALT and HASS”, Gregg Hobbs
11. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 11 September 12, 2013
WHAT IS HALT?
HALT: A design technique used to discover product
weaknesses and improve design margins. The intent is to
systematically subject a product to stress stimuli
well beyond the expected field environments in order to
determine and expand the operating and destruct limits of
your product.
- 50 Ways to Improve Your Product Reliability, Mike Silverman
12. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 12 September 12, 2013
WHAT IS HALT?
What do these definitions have in common:
Greatly accelerated process
Develop margins between spec and performance
Not just measuring margins but improving margins
Separating relevant from non-relevant failures
Starts early in design
Stresses are not limited to field stresses
Stresses are not limited to temperature and vibration
Power on and effective detection/monitoring
Combined Environment
Baby swimming (make more robust to real life later)
13. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 13 September 12, 2013
WHAT IS NOT HALT?
What are some classic HALT misconceptions:
My product does not experience vibration so we can’t use it
The spec for this component is 70C so we can’t go above that
in HALT
We can’t drill holes in the product because it will change the
airflow
We must mount it in the same direction as it will be mounted in
the field
We don’t need to go above the first failure point because that is
what will fail first
Run to preset levels (remember this is not a pass/fail test)
Don’t stress beyond specifications
Only perform HALT at system level
Just perform HALT only when diags are fully ready
14. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 14 September 12, 2013
WHAT IS NOT HALT?
And a few more…
HALT is for electronic equipment only
We can’t separate out this assembly because it will change the
thermal and vibration characteristics of the product
We shouldn’t defeat protection circuitry because the product
will never experience higher than this stress.
Performing each individual stress is the same as combined
stresses
A G is a G
15C per minute is a limit of the technology
and my favorite…
you can only perform HALT in a HALT Chamber
What other ones can you think of ?
15. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 15 September 12, 2013
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in equipment
5) What % of companies are doing HALT
6) What lies in the future for HALT
16. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 16 September 12, 2013
Stress
Start low and step up the
stress, testing the product
during the stressing
BASICS OF HALT
17. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 17 September 12, 2013
Failure
Gradually increase
stress level until a
failure occurs
Stress
BASICS OF HALT
27. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 27 September 12, 2013
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in equipment
5) What % of companies are doing HALT
6) What lies in the future for HALT
28. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 28 September 12, 2013
HALT vs. DFR
DfR is knowledge-based engineering wherein,
starting with capture of requirements and leading to
assured reliability, a reliability plan is designed and
executed using the full skills and knowledge of the
project team. The goal of DfR is to work smarter
through knowledge-based tailoring of the reliability
plan.
HALT is one of the tools used during a DFR program
to help improve and then prove the product reliability
goals. It is one of the most effective tools but is still
just one of the reliability tools used.
This is often forgotten by engineers.
29. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 29 September 12, 2013
HALT vs. DFR
30. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 30 September 12, 2013
Goal
Setting
Assess-
ment
Bench-
mark
FTAFMEA
Golden
Nuggets
Component
Selection
Predict-
ions
Thermal
Analysis
Derating
Analysis
POF
DOE Tolerance
Analysis
Preventive
Mainten.
EOL
Analysis
Warranty
Analysis
Test
Plan
HALT RDT ALT HALT-AFR
Calculator
FEA Software
Reliability
RCA CLCA
Vendor
Assessmt
HASS ORT OOBA
Lessons
Learned
Warranty
Returns
Reliability
Reporting
Statistics EDA for
Obsolesc
Out-
sourcing
Metrics
Reliability
Plan
CONCEPT
PHASE
DESIGN
PHASE
MANUFACTURING
PHASE
PROTOTYPE
PHASE
Gap
Analysis
Block
Diagrams
31. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 31 September 12, 2013
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in HALT methodology
5) What % of companies are doing HALT
6) What lies in the future for HALT
32. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 32 September 12, 2013
NEW ADVANCES IN HALT
Along with improvements in chamber technology,
there have been advances in the methodology as
well.
Harry McLean’s HALT Calculator
To determine “Guard Band” Limits during the
HALT Plan
To determine AFR after HALT
Using FMEA to determine specific areas to test for
Linking HALT to ALT
Using HALT for software/firmware issues
33. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 33 September 12, 2013
There are three different approaches to this problem
1) Physics of Failure
Drawback: Too many variables/Model becomes too complex
2) Weibull models/make general assumptions about acceleration factors or
plotting best fit curves.
Drawbacks:
a) Acceleration factors incorrect/Cannot be generalized
b) Existing models are for constant stress and not step stressing
c) Not enough HALT failures for statistically significant data
3) Model using HALT and Field Data
Drawback: requires a lot of data from many different types of products in many
different industries to develop an accurate model. No one had access to this
data…UNTIL NOW!
NEW ADVANCES IN HALT
HALT Calculator
34. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 34 September 12, 2013
• It is a provisional patent Excel-based mathematical model that,
when provided with the appropriate HALT and product information,
will accurately estimate the product’s field AFR or Actual field
Failure Rate.
• Three acceleration models are used, linear, exponential, and quadratic.
• The AFR Estimator has been validated on almost thirty products
from diverse design environments and manufacturers.
NEW ADVANCES IN HALT
HALT Calculator
35. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 35 September 12, 2013
Complete MTBF prediction
1. Use Telcordia, MIL-HDBK-217, or equivalent
2. Parts Count is acceptable
3. Ensure if you have a high failure rate item that you research and get supplier
test/field data to replace handbook data. The calculator is very sensitive to single
component weaknesses in HALT. Therefore, having prediction data for individual
components.
4. If you don’t have access to MTBF Prediction, use default prediction value
provided in model or use built in prediction estimator (model sensitivity to
prediction is relatively low so a default value is acceptable).
To Maximize Use of the ModelTo Maximize Use of the Model
NEW ADVANCES IN HALT
HALT Calculator
36. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 36 September 12, 2013
Complete HALT using the following guidelines:
1. Sample size of at least three, preferably four units.
Model can accommodate 1 to 6.
Realize that HALT sample sizes of three or less will dramatically
affect the ability to detect product defects and hence, the statistical
confidence is likewise, impacted.
1. Perform HALT at each phase of Product
Development Process to expand limits as much as
possible.
But use the results of your HALT later in product development
when samples are more abundant. HALT early in development is
a great idea but doesn’t give as good an input to the calculator.
1. Capture HALT Product Operational Response
Limits.
NEW ADVANCES IN HALT
HALT Calculator
37. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 37 September 12, 2013
New End Use
Prod Spec
End Use
Guard Band, Spec & End UseGuard Band, Spec & End Use
NEW ADVANCES IN HALT
HALT Calculator
38. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 38 September 12, 2013
• The model has not been validated on
mechanical designs.
• The estimate is as good as the test
protocol used in HALT and other reliability
tests.
• HALT does not capture every possible
design defect, i.e., humidity related issues,
field operation beyond Guard Band limits,
some wear-out mechanisms, etc.
Limitations of the ModelLimitations of the Model
NEW ADVANCES IN HALT
HALT Calculator
39. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 39 September 12, 2013
Published
Spec, °C
Level Application Guard Band, °C
0 to +40 1 Consumer -30 to +80
0 to +50 2 Hi-end Consumer -30 to +100
-10 to +50 3 Hi Performance -40 to +110
-20 to +50 4 Critical
Application
-50 to +110
-25 to +65 5 Sheltered -50 to +110
-40 to +85 6 All Outdoor -65 to +110
Product Type & Guard BandProduct Type & Guard Band
Product Environment & LevelProduct Environment & Level
NEW ADVANCES IN HALT
HALT Calculator
40. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 40 September 12, 2013
NEW ADVANCES IN HALT
HALT Calculator
Actual Field Failure Rate Estimate - % of Failures/Year
Input Matrix
Calculated MTBF (in Hrs) = 100,000
Product Thermal (Hot in °C) = 110
Product Thermal (Cold in °C) = -80
Product Vibration (in Grms) = 25
Prod Published Spec Level (see below) = 2
Number of HALT Samples = 6
Field Duty Cycle (in Percentage) = 80
Confidence = 1
Steady State AFR, % (HALT Only) = 0.30
Steady State Field MTBF, Hrs (HALT Only) = 2,893,373
Lower % HALT Confidence Limit = 1,829,861
Upper % HALT Confidence Limit = 4,682,531
41. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 41 September 12, 2013
Along with improvements in chamber technology,
there have been advances in the methodology as
well.
Harry McLean’s HALT Calculator
To determine “must meet” margins during the
HALT Plan
To determine AFR after HALT
Using FMEA to determine specific areas to test for
Linking HALT to ALT
NEW ADVANCES IN HALT
Use of FMEA
42. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 42 September 12, 2013
IEC 60601 3rd
Edition mandates that you must
understand your product risks before you can
develop a test plan
This is especially true of HALT
Understanding risks will help determine
What stresses to apply?
What are the limits to technology?
What test routines are needed to detect?
Are there any prognostics that will indicate failures
before the test routines pick up a hard failure?
NEW ADVANCES IN HALT
Use of FMEA
43. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 43 September 12, 2013
Along with improvements in chamber technology,
there have been advances in the methodology as
well.
Harry McLean’s HALT Calculator
To determine “must meet” margins during the
HALT Plan
To determine AFR after HALT
Using FMEA to determine specific areas to test for
Linking HALT to ALT
NEW ADVANCES IN HALT
HALT vs. ALT
44. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 44 September 12, 2013
HALT cannot find all types of failures
Mechanical wear failures
Other long term degradations (UV, corrosion, etc)
Failures due to process variations
NEW ADVANCES IN HALT
HALT vs. ALT
45. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 45 September 12, 2013
♦An Accelerated Life Test (ALT) is the
process of determining the reliability of a
product in a short period of time by
accelerating the use environment.
♦ALT is also good for finding dominant
failure mechanisms.
♦ALT is usually performed on individual
assemblies rather than full systems.
♦ALT is also frequently used when there is
a wear-out mechanism involved.
NEW ADVANCES IN HALT
HALT vs. ALT
46. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 46 September 12, 2013
Advantages of ALT
♦Instead of stepping up to failure, we
will pick a level that we know the
product will survive at (within relevant
failure area) and then run at this level
until failure.
♦This will characterize wear-out
mechanisms
NEW ADVANCES IN HALT
HALT vs. ALT
47. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 47 September 12, 2013
♦One key advantage of ALT over HALT is
when we need to know the life of the
product.
♦In HALT, we don’t concern ourselves with
this much because we are more
interested in making the product as
reliable as we can, and measuring the
amount of reliability is not as important.
♦However, with mechanical items that
wear over time, it is very important to
know the life of the product as accurately
as possible.
NEW ADVANCES IN HALT
HALT vs. ALT
48. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 48 September 12, 2013
Another advantage is that we often do not
need any environmental equipment.
Benchtop testing is often adequate.
NEW ADVANCES IN HALT
HALT vs. ALT
49. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 49 September 12, 2013
FAI LURE TESTI NG
HALT
OBJECTI VES
1. Root Cause Analysis
2. Corrective Action I dentification
3. Design Robustness Determination
TESTI NG REQUI REMENTS
1. Detailed Product Know ledge
2. Engineering Experience
ALT
OBJECTI VES
1. Reliability Evaluation (e.g. Failure Rates)
2. Dominant Failure Mechanisms I dentification
TESTI NG REQUI REMENTS
1. Detailed Parameters
(a) Test Length
(b) Number of Samples
(c) Confidence/ Accuracy
(d) Acceleration Factors
(e) Test Environment
2. Test Metrology & Fact ors
(a) 4:2:1Procedure Or Other
(b) Costs
ANALYTI CAL MODELS
1. Weibull Distribution
2. Arrhenius
3. Coffin-Manson
4. Norris-Lanzberg
NEW ADVANCES IN HALT
HALT vs. ALT
50. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 50 September 12, 2013
Cell Phone
Fan
Hard Drive
Infusion Pump
Medical
Cabinet
Robot
These pictures are samples of products we have tested.
These are not the actual products to protect the
proprietary nature of the products we test.
Automotive Electronics
NEW ADVANCES IN HALT
HALT vs. ALT
51. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 51 September 12, 2013
♦When wear-out is a dominant
failure mechanism, we must be
able to predict or characterize this
wear-out mechanism to assure
that it occurs outside customer
expectations and outside the
warranty period.
♦ALT is an excellent method for
doing this
NEW ADVANCES IN HALT
HALT vs. ALT - Summary
52. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 52 September 12, 2013
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in equipment
5) What % of companies are doing HALT
6) What lies in the future for HALT
53. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 53 September 12, 2013
What percentage of companies use the HALT
methodology?
I estimate about 50% of all companies in the US
have some form of reliability program.
I estimate about 50% of the companies that have
some form of reliability program are doing HALT.
This is based on projects we have worked with in
the past 3 years (about 750 clients). Of course
there are numerous companies that have no
formal reliability program.
This is up from 5% in 1995.
WHO IS USING HALT ?
54. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 54 September 12, 2013
1) What is HALT and What is Not HALT
2) Basics of HALT
3) Links between HALT and Design for Reliability
4) New advances in equipment
5) What % of companies are doing HALT
6) What lies in the future for HALT
55. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 55 September 12, 2013
The number of companies performing HALT will
continue to rise as more labs obtain HALT equipment
The need for more education will continue to increase
Standards/guidance docs will gain more importance as
more companies and labs are doing HALT, many
incorrectly.
Chambers will need to provide stresses in addition to
temperature and vibration to keep up with the physics
of the failures (especially due to smaller packages and
MEMs devices).
Move away from people and move to process
HALT as acronym will fade away
Less HALT and more emphasis on DFR including
HALT
FUTURE OF HALT
56. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 56 September 12, 2013
CONCLUSION
In this presentation
we took you through 40 years of HALT
showed you advances that have been made
pointed out areas where improvements are
still needed
57. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 57 September 12, 2013
THANKS!
QUESTIONS?
ANY QUESTIONS?
58. ASTR 2013 Oct 9-11, San DiegoMike Silverman, Ops A La Carte
40 Years of HALT: What Have We
Learned, Page 58 September 12, 2013
Mike Silverman
Ops A La Carte
Managing Partner
www.opsalacarte.com
mikes@opsalacarte.com
(408) 472-3889
Confidence in Reliability
CONTACT INFO
Notas del editor
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