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Practical Reliability Testing

Seminar for Test Engineers, Managers and Executives

1© 2009 Ops A La Carte


COMPANY OVERVIEW FOR

“Practical Reliability Testing Seminar”


COMPANY OVERVIEW

Confidence in Reliability


was named one of the top 10 fastest growing, privately-held companies in the Silicon Valley in 2006 and 2009 by the San Jose Business Journal.

Our Company

is a solid company that has been profitable every quarter since its inception due to its outstanding reputation, customer value and scalable business model.

is a privately-held professional reliability engineering firm founded in 2001 and headquarted in Santa Clara, California with offices in China, India and Singapore.


• Ops A La Carte is a Professional Reliability Engineering firm focused on providing confidence in reliability throughout the product life cycle.

• We offer a flexible method of engagement from end-to-end reliability solutions to solving specific problems to providing individual targeted reliability services.

• We do this through reliability assessment, consultation, testing, and training. We have our own Reliability Lab called HALT and HASS Labs where we have successfully helped customers improve the reliability on over 500 different products.

The Ops’ Value to its Customers


• Our Team:• Over 50 Consultants, each with > 15 years

experience• Partnership relationships with over 100 firms• Combined Sales Engineers and Program Managers• Core staff in project management, lab tech

services and accounting

• Continually expanding our geographic presence and industry expertise

Scalable Business Model


We tap into a large network of labs, test facilities, and talented engineering professionals to quickly assemble resources to supplement your organization. Below is a partial list:

Our Partnerships

• Analog/Digital Design Firms – Nuvation, Voler• Battery Design – Portable Power• Compliance/EMI – SEL, NTS,Intertek, SGS, MET Labs, UL• Component Kitting – Advanced Material Solutions• Contract Manufacturer – Paramit, Hunter, NPI Solutions• Environmental Labs – Most of the Major Test Labs• Failure Analysis Labs – DfR Solutions, Exponent, EAG• Fulfillment/Supply Chain Management - Extron• HALT Facilities – Qualmark, Reliant Labs, SGS, Trace, DfR• Mechanical/Product Devel. – Fusion Design, Triple Ring, Speck Design• Power Electronics – TD Systems• Quality Training – Swartz and Associates, Peak Consulting• RoHS/Lead Free – Design Chain Assoc., DfR Solutions, CALCE• Safety Engineering – Apogen• Sheetmetal Fabrication - Aitronics• Software Reliability – RHM Associates, SoftRel• Structural Analysis – PEC Engineering, Ozen Engineering• Test Engineering – Solution Sources Programming• Thermal Consultants - eCooling• Verification/Validation – Integrated Compliance Engineering• Warranty Assessment and Analysis – RHM Associates


The PRG is a “one-stop-shop” of outsourced services that helps companies to bring new products to market. Partners include:

Senior Partner in Product Realization Group


Industry PenetrationWe have over 500 customers across 100 different industries, including:

AEROSPACEAGRICULTURE/FARMINGAIRPORT SECURITYALTERNATIVE ENERGYARMED FORCESAUDIO AND VIDEOAUTOMATIONAUTOMOBILE/TRUCKING AUTOMOTIVE COMPONENTSBANKING/AUTOMATIC TELLER EQUIP.BATTERIESBEVERAGE INDUSTRY EQUIPMENTBIOMEDICALBOATINGBUILDING MATERIALSCABLE INDUSTRYCHAMBER MANUFACTURERCOMPUTERSCONSUMER ELECTRONICSCONTRACT MANUFACTURINGCONTROL SYSTEMSCOSMETICSDEFENSE ELECTRONICSDESIGN AUTOMATIONDESIGN FIRMSDISK DRIVESDISPLAY ELECTRONICSELECTRIC METERSELECTRIC UTILITY COMPANYELECTRIC VEHICLESELEVATOR COMPANIESENGINEERING AUTOMATION TOOLSENVIRONMENTAL EQUIP.

ENVIRONMENTAL TEST LABFAILURE ANALYSIS LABFUEL CELLSFOOD INDUSTRYFOOD PACKAGING PRODUCTSGAMING INDUSTRYGENERATORSGOVERNMENT RESEARCHGPS INDUSTRYHANDHELD METERSKITCHEN APPLIANCESLASERSLEGAL INDUSTRYLIGHTING INDUSTRYMAGAZINE/MAIL ORDER INDUSTRYMEDICAL DEVICESMETERS, ELECTRIC/GASMETERS, HANDHELDMININGMOBILE PHONEMOTORS AND ENGINESNETWORK APPLIANCESNETWORK SECURITYNETWORKINGNUCLEAROIL EXPLORATIONOPTICAL COMPONENTSPET TOYSPCB MANUFACTURERSPERIPHERALSPHARMACEUTICALSPOINT OF SALE DEVICESPOWER STATIONS

POWER SUPPLIESPRINTERSRADIO/RF/MICROWAVERECREATIONAL/SPORTSRELAXATION PRODUCTSRESTAURANT EQUIPMENTRF COMPONENTSRFIDROBOTICS, MEDICALROBOTICS, SEMICONDUCTORSATELLITESCIENTIFIC RESEARCHSEARCH ENGINESECURITY SYSTEMSSEMICONDUCTORSEMICONDUCTOR MFG EQUIPSOCIETIESSOLAR INDUSTRYSOLID STATE STORAGESPACE EXPLORATIONSPORTS EQUIPMENTSPORTS MEDICINESTORAGE NETWORKINGTELECOMTEST & MEASUREMENTUNDERWATER ELECTRONICSUNIVERSITIESVETERINARYVISION SYSTEMSWATER PURIFICATIONWEATHER RESEARCH PRODUCTSWINDWIRELESS


2010 Specific Industry Focus

Currently, our top four industries are…

MedicalClean-TechOil and Gas

Defense/Aerospace


Our Customers in N.America


Our Customers Around the World

{Singapore


Ops’ New Reliability BookHow Reliable Is Your Product?

50 Ways to Improve Product Reliability

A new book by Ops A La Carte LLC® Founder/Managing Partner Mike Silverman

The book focuses on Mike’s experiences working with over 500 companies in his 25 year career as an engineer, manager, and consultant. It is a practical guide to reliability written for everyone in your organization. In the book we give tips and case studies rather than a textbook full of formulas. Available January 2011 in hardback for $44.95 or ebook for $19.95 @amazon.com or http://www.happyabout.com/productreliability.php For more info, go to www.opsalacarte.com


Practical Reliability Testing

BySteve Brenner, Ops Senior Reliability Test Engineer

Mike Silverman, Ops Managing Partner


Seminar Overview Most reliability testing involves time and money. How do

we best use money and resources to develop a reliable product?

Practical Reliability Testing is about meaningful short term tests which add to product robustness and to the company bottom line.

Review of actual test programs which yielded results for a very limited test costs.

In most cases, Clients need to know the product MTBF or the failure causes (AFR) of a product in the field.

Interactive Participation

Questions have been submitted by participants Further questions will arise during seminar, please

forward to mikes@opsalacarte,com We will do our best to respond, but due to time

limitations may not get to you all. In this case, OPS will answer your questions by

email or telecom as it best suits the answer(s)


Seminar Schedule9:30 am-Welcome to OPS Interactive Seminar Series10:00 am Failure Modes Tailored Accelerated Testing

10:45 am Forensic Accelerated Life Testing 11:30 am Q&A Your Reliability Issues

12:00 -1:00 pm Lunch 1:00 pm HALT AFR an Emerging Methodology

2:30 pm - Q&A Your Reliability Issues



Tailoring Environmental Tests for

Known Failure Modes


OverviewHighly Accelerated Life Testing (HALT) has standard methods of performance, designed to find future failure modes in a very short time.

Commercial (IEC) and Military (MIL-STD-810) Specifications have specific protocols for simulating service conditions for design verification testing.

We can tailor these environments to reproduce failures found in service use quickly and efficiently.


Example 1

Using HALT to Improve on Reliability for MCM Field

Failures

MCM’s (Membrane Cooling Modules) are failing in the field after on average 7 months of use.

Problem Statement

“The seal of the failed MCM was examined under a microscope. On both failed samples it was observed that the film had separated between the polyethylene and nylon. The leak had penetrated through the polyethylene before the failed surface and separated the two films. The polyethylene was fused bonded to the frame at the failed location.”

Failure Description

• Four new alternative MCM designs, believed to be more robust, were created. Prototypes of each were manufactured, and made available for testing.

• But Client was not going to wait seven months to find out if the MCM solution would work

• More importantly the select design would have to demonstrate improved reliability over the previous model of MCM

MCM Alternative Solutions

1. High pressure testing up to 110 psi constrained in a special test fixture that mimicked the Test Head.

2. Possible effect of water hammer.3. Cross-sectional 4. Dimensional analysis.5. Water contaminants (Chemical & Particulate).6. Examine effects of contaminants (additives) in the

frame itself. (EVA, blowing agents)7. Peel testing to determine strength of seals

Attempts At Reproducing The Field Failure Modes

• None of the aforementioned methods was useful to evaluate the new designs versus the original over the long term.

• With tens of thousands of units in the field world wide, many approaching the seven month mark, a corrective decision needed to made quickly.

Corrective Action Needed

•Samples of the old design were made available for experimentation using HALT parameters.

•High and Low Temperature step stress testing was performed with the units under normal working pressure, to determine at what points the seals would delaminate due to over-temperature.

HALT Environment

MCM s in HALT Environment

Close-up of HALT Setup

The Next Steps

•With the temperature operating limits known, test units were exposed to rapid (>60˚C/min) temperature cycling with various operating pressures.

•After four days of experimentation, parameters were discovered that could reproduce the exact failure mode in three hours of chamber time.

Reproducing the Precise Failure Mode

• Overall only 5 days of testing • All four new designs were

evaluated; best design selected • Optimum design immediately put

in to production• Field solution implemented

HALT Leads To Results

Example 2

Recording Dynamic Data on a Prototype Vehicle for

Design Verification

• An electronic assembly must be qualified for use on a unique vehicle.

• What can be used for vibration and shock design parameters other then analytically determined values

• What can be used for Design verification instead of either “Generic” test parameters or parameters determined analytically?

Problem Statement

Resolution for Parameter Identification:

•Record vibration and shock levels on a prototype vehicle

•Provide the data to designers for appropriately ruggedized design

•Use the data to generate realistic test parameters for Design Verification testing

Test Parameter ID Method

Sensors installed at projected mounting point of electronics assembly.

Vibrations Chamber Setup

The Data Collection Procedure:

•Install sensors close to planned mounting points of of Electronics Assembly .

•Simulate all projected service conditions for vibration and impact.

•Record data in time domain to allow for multiple analysis methods.

Data Collection

Sample of Vibration Data (PSD)

Sample SRS Data

Data Collected Used to Identify Test Parameters:

•Provided Power Spectral Density data and Shock Response Spectra to designers.

•Used Power Spectral Density data and Shock Response Spectra to create meaningful test parameters.

Test Parameter Identification

Final Electronic Assembly in Design Verification

Testing

Conclusions Vibration setup of electronic assembly allowed data

collection of possible real world loading conditions Most relevant was positioning sensors for recording data

in time domain to allow for multiple analysis methods Data collected provided Power Spectral Density data and

Shock Response Spectra to designers. Used Power Spectral Density data and Shock Response

Spectra to create test parameters Conducted design verification and qualification on

electronic assembly to prove durability for load spectrum



Accelerated Life Testing of Thermoplastic Polyurethane

(TPU) Insulation

Problem Statement Consumer Products warehoused in Georgia experienced

insulation degradation Actual degradation, remaining insulation life if damaged

and expected life of undamaged insulation all needed evaluation

The product in question: a thermoplastic polyurethane (TPU) but unknown if it is ester or ether based.


Sample Undamaged Specimen

Sample has visible surface oily residue

TPU wire is 1/8” ϕ Most samples are

cracked or cracks are being initiated

Millions at stake


Properties of TPU Understand properties

helps to know how to accelerate testing

Unknown whether it is ether or ester based

Polyether based TPU resistant to hydrolysis

Polyester based TPU is resistant to temperature

Standard Properties

Range

Max Operating Temperature

-40C to 80C

Proper Storage Temperature

23 C / 74 F

Proper Storage Rel. Humidity

50%

Activation Energy

0.2-1.0 eV

Heat of Combustion

25,000-29,000 J/g


Strength vs Weaknesses

Polyester Based: Highest heat resistance Highest mechanical

properties Highest resistance to

mineral oils

Polyether Based: Highest hydrolysis

resistance Best low-temperature

flexibility Resistance to

microbiological degradation


Hydrolysis Effects on TPU


Failure Parameters Based on material properties and trends, the failure

parameters need to be identified Analysis evaluates possible acceleration factors and will

provide some foundation for forensics Temperature, hydrolysis and other environmental factors

specific to storage location have to be isolated Eliminate the outliers such as biological factors, potential

chemical exposure and mechanical stresses


Types of Reliability Testing

Types of reliability testing:1. HALT (AFR)2. ALT3. RDT

Choose Accelerated Life Testing because MTTF is desired


Acceleration Factors, Af for Temperature and RH

Af refers to the amount of energy required to initiate an internal chemical change

As identified the activation energy for TPU is 0.2-1.0 eV

Af depends on choice for activation energy

Test Temp ©

Relative Humidity

Accel.Factor

20 75% 2.740 75% 12.160 75% 46.320 80% 3.240 80% 14.760 80% 56.220 85% 3.840 85% 17.760 85% 67.420 90% 4.640 90% 21.060 90% 80.020 95% 5.440 95% 24.760 95% 94.120 100% 6.340 100% 28.860 100% 109.8


Forensic ALT

Objective is to determine the MTTF using major stressors, adequate sample size and confidence level

25 test samples 50, 100, 150 and 240

test hours 75%, 80%, and 90%

confidence levels Combined Af of 3, 15,

21


MTTF Calculations


Test Methodology

High confidence requirement means 90% level Combined stressors (temperature and humidity Not all TPU will have aged at the same rate Stepped temperature approach, incremental

changes allow for early failures of TPU Let the Customer decide the desired temperature,

suggested between 40°C-60°C


Test Methodology (cont’d) 10°C increments for 10 minutes up to the upper

functional operating temperature limit. At the end of each temperature step perform a visual check

for cracks or crack initiation of the insulation. If a failure is visually found, note the failed temperature

and quantity of failure. Remove the sample and replace with another sample.

Add the relative humidity to 90% wait for temperature to stabilize, since there will be a drop with water vapor

The expected acceleration and hence degradation of the TPU insulation will have been reached.


Visual Checks and Balances

The specimens were to be visually checked every hour over a normal working day.

Failure will likely be rapid with the onset of an initial crack and subsequent propagation.

After reaching the first 50 hours of testing, a MTTF can be determined from calc Table

Could continue to the next milestone of 100 hours and so on up to 200 hours


Some Calculations

50 hours at 40 C / 80% RH we had seven (7) failed out of 25 specimens1. MTTF = 1593 @ 90 % confidence2. MTTF = 1832 @ 80 % confidence3. MTTF = 1936 @ 70 % confidence


Conclusions Isolated failure parameters, identified two as possible

stressors and determined acceleration factors Provided MTTF table with acceleration factors for relative

humidity and temperature with sample size of 25 Customer decided on temperature 40C, relative humidity

of 80% giving us an acceleration factor of 15 7 of 25 samples failed after only 50 hours of testing ALT provided MTTF of 1593 at a confidence of 90% Forensically, testing confirmed stressors, failure

mechanisms (cracking and propagation through the TPU) Limited test time and cost (2.5 days of lab time)


Questions


Thank you for your attention.

Do you have any questions?


LUNCH BREAK BE BACK AT 1:00 pm


HALT-to-AFR Calculator


Highly Accelerated Life Testing -HALT

LAUNCH POLL 6Do you currently perform HALT?

© 2009 Ops A La Carte

HALT: A design technique used to discover product weaknesses and design margins. The intent is to systematically subject a product to stress stimuli well beyond the expected field environments in order to determine the operating and destruct limits of your product.- 50 Ways to Improve Your Product Reliability, Mike Silverman

What is HALT?

HALT, How It Works

HALT, Why It WorksClassic S-N Diagram

(stress vs. number of cycles)

N0

S0= Normal Stress conditions

N0= Projected Normal Life

S1

S2

N1N2

S0

HALT, Why It WorksClassic S-N Diagram

(stress vs. number of cycles)

N0

S0= Normal Stress conditions

N0= Projected Normal Life

S1

S2

N1N2

Point at which failures become non-relevant

S0

Product Operational

Specs

Stress

Upper Oper. Limit

Upper Destruct

Limit

Lower Destruct

Limit

LowerOper. Limit

Margin Improvement Process

Product Operational

Specs

Stress

Upper Oper. Limit

Upper Destruct

Limit

Lower Destruct

Limit

LowerOper. Limit

Margin Improvement Process

Operating Margin

Destruct Margin


Reliability Demonstration Testing (RDT)

LAUNCH POLL 7Do you currently perform RDT?

What is RDT? For Reliability Demonstration Testing (RDT), a sample of

units are tested at accelerated stresses typically for several months.

The stresses are a bit lower than the HALT stresses and they are held constant (or cycled constantly) rather than gradually increasing.

This enables us to calculate the acceleration factor for the test.

The RDT can be used to validate the reliability prediction analyses.

RDT, continued

CRE Primer by QCI, 1998


Overview of HALT vs. RDTHighly Accelerated Life Testing (HALT) is a great reliability technique to use for finding predominant failure mechanisms in a hardware product. However, in many cases, customers need to know the MTBF or Annualized Failure Rate (AFR) of a product in the field. When this is the situation, many people turn to Reliability Demonstration Testing (RDT).


The problem with an RDT is– Test takes too long– Test is too expensive

HALT Calculator solves this– The model is not based on Physics of Failure or based on derived

acceleration factors. Instead, the model was created by developing a correlation map

– We mapped 15 years of past HALT data to field data on the same products.

– We are the only company in the world that has successfully created a HALT Calculator.

– We have applied for a US Patent on this Calculator

The problem with an RDT is– Test takes too long– Test is too expensive

HALT Calculator solves this– The model is not based on Physics of Failure or based on derived

acceleration factors. Instead, the model was created by developing a correlation map

– We mapped 15 years of past HALT data to field data on the same products.

– We are the only company in the world that has successfully created a HALT Calculator.

– We have applied for a US Patent on this Calculator

Overview


Summary of the AFR Estimator The AFR Estimator is a patent pending mathematical model that,

when provided with the appropriate HALT and product information, will accurately estimate the product’s field AFR or Annual Failure Rate.

This methodology has been used on a number of products with significant positive financial results.

The AFR Estimator has been validated on over thirty products from diverse manufacturers and design environments.

The model can accommodate HALT samples sizes from one to six with the optimum size being four. Sample sizes of greater than four will default to four.

90% upper and lower confidence limits are calculated based on the HALT AFR and the HALT Sample Size.


History of Model

• Began developing a model in 2000.• Collected data for model between 2000 and 2007.• Demonstrated model to 3 engineers in 2008.• Obtained validation data from others late 2008.• Validated model in 2009.

• Began developing a model in 2000.• Collected data for model between 2000 and 2007.• Demonstrated model to 3 engineers in 2008.• Obtained validation data from others late 2008.• Validated model in 2009.


Complete MTBF prediction1. Use Telcordia, MIL-HDBK-217, or equivalent2. Parts Count is acceptable3. Ensure if you have a high failure rate item that you research

and get supplier test/field data to replace handbook data. Thecalculator is very sensitive to single component weaknessesin HALT. Therefore, having prediction data for individualcomponents.

4. If you don’t have access to MTBF Prediction, use defaultprediction value provided in model (model sensitivity toprediction is relatively low so a default value is acceptable).

Complete MTBF prediction1. Use Telcordia, MIL-HDBK-217, or equivalent2. Parts Count is acceptable3. Ensure if you have a high failure rate item that you research

and get supplier test/field data to replace handbook data. Thecalculator is very sensitive to single component weaknessesin HALT. Therefore, having prediction data for individualcomponents.

4. If you don’t have access to MTBF Prediction, use defaultprediction value provided in model (model sensitivity toprediction is relatively low so a default value is acceptable).

To Maximize Use of the Model


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 dramaticallyaffect the ability to detect product defects and hence, thestatistical confidence is likewise, impacted.

2. Perform HALT at each phase of Product Development Process toexpand limits as much as possible.

But use the results of your HALT later in product developmentwhen samples are more abundant. HALT early in developmentis a great idea but doesn’t give as good an input to the calculator.

3. Capture HALT Product Operational Response Limits.4. Correct all issues at least up to Guard Band Limits (beyond, preferably).

Continued

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 dramaticallyaffect the ability to detect product defects and hence, thestatistical confidence is likewise, impacted.

2. Perform HALT at each phase of Product Development Process toexpand limits as much as possible.

But use the results of your HALT later in product developmentwhen samples are more abundant. HALT early in developmentis a great idea but doesn’t give as good an input to the calculator.

3. Capture HALT Product Operational Response Limits.4. Correct all issues at least up to Guard Band Limits (beyond, preferably).

Continued



A few more guidelines:5. Ten minute (or greater but consistent) dwells for thermal and

vibration.6. Include rapid thermal and combined environments

(this is accounted for but not used as user inputs to model).7. Test product throughout. Use a robust test protocol and make sure you

test all interfaces in HALT.8. Include stresses beyond just temp/vib. Use FMEA to determine best

set of stresses.9. Provide complete and timely corrective actions from HALT failures.

The better the C/A, the more you can expand limits.10. Use the same configuration for HALT as the what you plan to ship.

A few more guidelines:5. Ten minute (or greater but consistent) dwells for thermal and

vibration.6. Include rapid thermal and combined environments

(this is accounted for but not used as user inputs to model).7. Test product throughout. Use a robust test protocol and make sure you

test all interfaces in HALT.8. Include stresses beyond just temp/vib. Use FMEA to determine best

set of stresses.9. Provide complete and timely corrective actions from HALT failures.

The better the C/A, the more you can expand limits.10. Use the same configuration for HALT as the what you plan to ship.



New End Use

Prod Spec

End Use

Guard Band, Spec & End Use


Accelerated Time Scale

Field Use Time Scale

Time

t0 t1 t2 t3

t0 t1 t2 t3

Two other acceleration models are used in the estimation equation - exponential and quadratic

Linear Acceleration


• HALT AFR:• AFR,ƒ (MTBF*Factor1, Thermal Range*Factor2,

Vibration*Factor3,Vibration Table*Factor4, Sample Size*Factor5)

• Confidence Limits:• Chi Squared (2) from Semi E10 (based on HALT AFR,

HALT sample size, and number of failures)• Sample Size n = (Zα+Zβ)2*p*(1-p)/d2

• Days for Detectable Shift in AFR (HASS) = n/Sample Size

• HALT AFR:• AFR,ƒ (MTBF*Factor1, Thermal Range*Factor2,

Vibration*Factor3,Vibration Table*Factor4, Sample Size*Factor5)

• Confidence Limits:• Chi Squared (2) from Semi E10 (based on HALT AFR,

HALT sample size, and number of failures)• Sample Size n = (Zα+Zβ)2*p*(1-p)/d2

• Days for Detectable Shift in AFR (HASS) = n/Sample Size

Overview of Equations


• The model has not been validated on mechanical designs.

• The estimate is as good as the test protocol used in HALT andother reliability tests. HALT does not capture every possibledesign defect, i.e., humidity related issues, field operationbeyond Guard Band limits, some wear-out mechanisms, etc.

• The units in HALT need to be tested with a protocol thatsufficiently tests the product in each stress environment. If thetest coverage cannot find an issue, it cannot be included in themodel.

Limitations of the Model


Increasing the Model Accuracy

1) Defeat thermal cut-offs2) Build extender cables to separate the stress

sensitive assemblies3) After discovering issue, work around it to find next

failure. Continue until FLT.4) Provide C/A for each issues. The better the C/A,

the higher the limit you can use for the model and the lower the field AFR.

1) Defeat thermal cut-offs2) Build extender cables to separate the stress

sensitive assemblies3) After discovering issue, work around it to find next

failure. Continue until FLT.4) Provide C/A for each issues. The better the C/A,

the higher the limit you can use for the model and the lower the field AFR.


For HALT• HALT takes a few days to run and to implement its corrective

actions, and even if it’s a bit longer, this time would be far lessthan waiting for an RDT to run and to implement its correctiveactions.o It can be a huge time and cost saver, especially warranty.o Can accurately estimate the field AFR before launch.o Meeting stress levels in the Product Environment Table

can ensure the product exceeds customer expectations.• With 7 data points the AFR Estimator can provide accurate

field AFR instantaneously and 90% statistical confidencelimits based on HALT sample size and AFR.

For HALT• HALT takes a few days to run and to implement its corrective

actions, and even if it’s a bit longer, this time would be far lessthan waiting for an RDT to run and to implement its correctiveactions.o It can be a huge time and cost saver, especially warranty.o Can accurately estimate the field AFR before launch.o Meeting stress levels in the Product Environment Table

can ensure the product exceeds customer expectations.• With 7 data points the AFR Estimator can provide accurate

field AFR instantaneously and 90% statistical confidencelimits based on HALT sample size and AFR.

82

Why Use the AFR Estimator ?


Product Type & Guard Band Match your product's Published Specifications to a

corresponding Level number listed in the table below, i.e., a high-end consumer product equates to a Level 2.

If the product does not meet the selected Category with its associated Guard Band Limits, it will have a higher estimated AFR.

Enter the corresponding Level number from the table below. Enter the value in the table in Section H. Note: The Categorycolumn description may not exactly match your company's description for the product’s field application. This is a very important factor in estimating the AFR.


PublishedSpec, 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 Environment & Level


HALT CalculatorField Failure Rate Estimate - % of Failures/Year

Input Matrix Data VerifiyMTBF (in Hrs) = 40,000 OK Key

Product Thermal (Hot in °C) = 94 OK User inputProduct Thermal (Cold in °C) = -58 OK Calculated

Product Vibration (in Grms) = 80 OK SelectionProd Published Spec Level (see below) = 3 OK Data Validity

Number of HALT Samples = 4 OK

Steady State AFR, % (HALT Only) = 1.06Steady State Field MTBF, Hrs (HALT Only) = 822954

Lower 90% HALT Confidence Limit = 443657Upper 90% HALT Confidence Limit = 1691518

Published Spec Level # Guard Band Limits0 to +40 1 Consumer -30 to +800 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


Calculated HALT Results Table AFR, % ReturnProducts: MTBF AFR, % Hot Cold Vib Level Tech HALT Calc Field Act Rate, %

Display 415,000 2.1 130 -80 28 4 2 0.27 0.21Outdoor 175,800 5.0 100 -60 28 6 3 1.26 0.75 8.30Vehicle 143,600 6.1 102 -67 20 6 2 1.35 1.05 2.80Vehicle 342,100 2.6 100 -30 31 2 2 1.07 0.70 5.60

Outdoor 275,000 3.2 110 -60 17 6 3 1.40 0.30 3.70Vehicle 157,100 5.6 90 -60 21 2 2 1.17 0.90 10.10Vehicle 192,500 4.6 90 -60 21 5 2 1.15 1.00 9.80Vehicle 106,800 8.2 100 -50 13 2 2 2.27 2.20 14.06Hi Perf 616,200 1.4 110 -42 19 3 3 1.28 1.00Vehicle 56,800 15.4 80 -35 17 3 2 3.40 3.75Vehicle 109,800 8.0 105 -35 14 6 2 3.25 4.40 8.40

Office 3,199,090 0.3 80 -50 20 1 2 1.35 0.8 1.4Telecom (Out) 200,000 4.4 100 -80 28 6 1 0.83 0.5

Telecom 200,000 4.4 83 -82 31 4 1 0.88 0.5Telecom 200,000 4.4 85 -60 50 4 1 1.21 0.5Telecom 200,000 4.4 121 -54 21 4 1 1.06 0.5Telecom 200,000 4.4 102 -72 25 4 1 0.82 0.5

Consumer 70,000 12.5 100 -30 10 1 2 5.31 3.00Consumer 70,000 12.5 100 -30 16 1 2 3.13 3.00Consumer 70,000 12.5 90 -30 19 1 2 2.82 2.92

Avionics 17,000 51.6 120 -70 48 4 3 1.18 1.36 1.89Avionics 32,000 27.4 125 -100 48 4 3 0.39 0.78 1.61Avionics 14,000 62.6 120 -60 50 4 3 1.87 1.55 2.12Avionics 18,900 46.4 120 -80 62 4 3 0.89 1.78 2.49Avionics 20,600 42.6 120 -90 65 4 3 0.57 1.16 2.43Avionics 14,600 60.0 120 -90 55 4 3 0.81 0.16 0.61Avionics 71,000 12.3 120 -65 40 4 3 0.86 0.51 1.08Avionics 11,000 79.7 125 -70 25 4 3 1.34 0.36 2.08

Weighscale 50,000 17.5 90 -50 15 1 2 2.92 1.95

Validation Table (29 samples)


Justification for the AFR Estimator

As HALT takes only a few days to run and to implement its corrective action(s), and even if it took a bit longer, this time would be far less than waiting for an RDT to be run and to implement its corrective action(s). The application of this model can be a huge time and cost saver.

As higher HALT limits equate to lower AFR, you now have a tool that can accurately estimate the field AFR before launching the product. Stress levels that are depicted in the table in Section E are highly recommended for HALT. These levels can assure the producer that the product will exceed customer expectations and allow the producer to accurately forecast warranty expenditures.


• The methodology works very well.• Would like more data – would you like to help?

• LAUNCH POLL 8• Do you have any field data for products in which you have

performed HALT?

• The methodology works very well.• Would like more data – would you like to help?

• LAUNCH POLL 8• Do you have any field data for products in which you have

performed HALT?

Conclusions


Questions

Thank you for your attention.

Do you have any questions?

HAND OUT SURVEYS


Reliability SymposiumMay 9-13

Santa Clara and via webinarTRACK 1: DFX TOOLS Design for Reliability (DfR) – May 9-10 Design for Mechanical Reliability (DfMR) – May 11 Design for Warranty (DfW) – May 12 Design for Software Reliability (DfS) – May 13

TRACK 2: REL TOOLS: ALT/DOE/RCA Design of Experiments – May 9-10 Best Accelerated Tests (BART) – May 11-12 Root Cause Analysis - May 13

Details for all are on the Ops Education Schedule for 2011


Future Seminars/Webinars/Events

ALL ARE FREE Feb 17 – Medical Device Seminar/Webinar, San Jose Mar 2 – Warranty Webinar (coincides with Warranty Chain

Management Workshop on March 17) Mar 3 – Implantable Medical Seminar, Santa Clara Mar 22 – Book signing for “How Reliable Is Your Product”,

Santa Clara Apr 6 – Solar Reliability Challenges May 3 – DfSS vs. DfR Webinar (tied with WQC) Jun 7 – How to Use HALT with Prognostics (tied with PHM)

Details for all are on the Ops web site www.opsalacarte.com

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