HALT and HASS - NEURTEK · 2016. 6. 14. · HALT, that has shifted the limits found in HALT. Ultimately, its purpose is to prevent flawed units from reaching the end-user/customer.

HALT and HASSTest Equipment For Highly Accelerated

Life Test and Stress Screen Applications

Weiss Umwelttechnik GmbHSimulationsanlagen Messtechnik

NEURTEK S.A. T. +34 943 82 00 82 [email protected] www.neurtek.com

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HALT/HASS SystemsHighly Accelerated Life Test andStress Screen ApplicationsThe goal of every manufactu-ring company is to bring a pro-duct of worldclass quality tomarket in the shortest time andfor the least expense. On top ofthat there is a further incentiveto improve field reliability and

Reliable test results by meansof reproducible environmentalconditionsCharacteristics, function andservice life of systems or com-ponents are influenced by vary-ing thermal and climatic condi-tions during transport, storageand use.

For this reason, tests have to becarried out in order to safe-guard and optimise the qualityof the product.

The temperature and climatetest chambers produced byWeiss Umwelttechnik set stan-dards with regard to ease ofoperation, performance andequipment.

Weiss Umwelttechnik GmbH isone of the leading manufactu-rers of test devices and systemsfor environmental simulationworldwide.

The product range comprisestest systems of all test chambervolumes for temperature andclimatic testing, simulation ofexposure to weather, tempera-ture shock, corrosion and long-time testing – in research, deve-lopment, quality control andproduction.

Walk-in systems and in-lineplants are designed, producedand installed in accordance withcustomer specifications.

An excellent after-sales serviceensures optimum support forour customers and a highdegree of operational safety ofour systems.

lower warranty costs. Manymanufacturers use HALT andHASS to help them achievethese goals.

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Highly Accelerated Life Test and Stress Screen Applications

implemented and product limitsare understood and expanded.Information learned during theHALT process is used to developa HASS screen for monitoringdeviations in the manufacturingprocess.

HASS is a post-production pro-cess that can be performed on100 % of product or a partialsample of units (HASA - HighlyAccelerated Stress Audit).

The main goal of HASS is to pre-cipitate and detect hidden orlatent failures. It is used to ver-ify that no new “weak link” hascrept into the product, sinceHALT, that has shifted the limitsfound in HALT. Ultimately, itspurpose is to prevent flawedunits from reaching the end-user/customer.

Typically, HASS stress levels areless than those used in HALT.However, they are generallymore severe than anticipated inactual service. The goal is touse enough stress to find faults- but not enough to remove asignificant amount of the pro-duct’s life.

The benefits of HASS include:

Precipitates hidden or latentfailures caused by poorworkmanship or manufactu-ring processesVerifies integrity of mechani-cal interconnectsPrevents flawed units fromreaching the end-user/ customer (infant mortality/out of box failure)Detects changes in compo-nents and processesDecreases warranty and field service costsExposes process related variations in manufacturingUncovers problems causedby changes to both softwareand firmwareUncovers component supplierquality issues and revisionchangesIncreases customer satisfac-tion

HALT is a step stress processperformed during the product’sprototype phase that determinesa product’s operating limits,identifies design weaknesses,and identifies weak compo-nents. The prototype phase isthe fastest and least expensivepoint to make improvements.

In the HALT process, the testsample is subjected to progres-sively higher stress levels.Thermal dwells, rapid tempera-ture transitions, vibration, and acombination of temperatureand vibration are employed toprecipitate latent, inherent de-fects in the design, at the com-ponent level, or in the manufac-turing process.

Beyond the precipitation ofdefects, HALT stresses the pro-duct sample to failure. Robust-ness of design and marginabove the product’s intendedoperating level are determined.HALT is not a pass/fail test. It isprocess of discovery and designoptimization.

HALT is a success when failuresare produced, the root cause isunderstood, corrective action is

HALT precipitated defects by stress environment HASS precipitated defects by stress environment

Vibration step stress= 45%

Combination of6DoF Vibration andRapid Temperature

= 20%

Hot stepstress= 17%

Cold step stress= 14%

Rapid Temperature Transitions= 4%

Combinationof 6DoF Vibration and Rapid Temperature= 46%

Extreme TemperatureTransitions

= 12%

HighTemperature

Extreme= 12%

LowTemperature

Extreme= 12%

Vibration= 18%

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The HALT ProcessIn HALT, product prototypes aresubjected to high levels of envi-ronmental stress from leastdestructive to most destructive.The HALT procedure employedwill vary based on the type ofproduct being tested. Typicallythese would be cold step test,hot step test, thermal shock,vibration and combined tempe-rature and vibration.

Along with environmental stres-ses, product specific stressesshould also be applied to theproduct, such as power cycling,line voltage margining, line fre-quency margining, DC supplyvoltage margining, output loa-ding, onboard oscillator margi-ning and any other applicablestresses.

Test repeatability is the ability toreproduce a failure mode; how -ever, exact stress levels to pro-duce the failure may vary.Reproducing a failure mode at aspecific stress level is not expec-ted or required. In HALT what isimportant is the failure, not thestress level.

Example: Temperature-StepPortion of HALT

Cold or Hot step stresses in10 °C steps.Power cycling performed atminimum operating tempera-ture +10 °C.Add power cycling and voltage margining to findadditional failures. Voltagemargins should be testedbeyond specifications toexpose design problems.

HALT and HASS profile graphs appear courtesy of Reliant Labs.

Example: Thermal ShockPortion of HALT

5 thermal cycles with thermalchange rates of 50 °C perminute (or greater).

Rapid thermal cycling causesmaterials in the product toexpand and contract at differentrates, inducing stress and unco-vering weak spots in the design.

Example: Vibration-StepPortion of HALT

Step stress vibration in 5 gRMSincrements, starting at 5 gRMS.

Once a diagnostic check hasbeen completed, vibration tes-ting continues at the next level.

With our powerful StarView soft-ware, you have the ability tomonitor your product responseas well as the table vibrationlevels.

Example: CombinedTemperature and VibrationPortion of HALT

Perform thermal cycles withthermal change rates of 50 °Cper minute (or greater).Increase in 20 % incrementsof the operating limit. Dwelltimes of 15 minutes.

If no failure is produced, the rateof temperature change is increa-sed and the vibration levels areincreased.

HALT-HASS Profiles

Examples of typical HALT profiles

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When a failure occurs, the test isstopped and the failure modeand stress level is recorded. Thefailure is identified and docu-mented. Root Cause Failure Ana-lysis is employed.

At this point a temporary “fix” isimplemented and the test conti-nues on to higher levels of stressto uncover more failures.

HALT testing stops when thelimits of the test equipment aremet, when multiple failuresoccur in rapid succession withsmall increases in the stresslevel, or when the maximumlevel of the materials or techno-logy has been reached.

Information learned from theHALT test will provide the pro-duct’s operating limits and it mayalso provide destruct limits.

The operational limit is definedas the stress necessary to causea product to malfunction, but theproduct returns to normal opera-tion when the stress is removed.The destruct limit is the stressnecessary to cause a permanentor “hard” failure.

The difference between theselimits is the margin for that par-ticular stress. As the failuremodes are found and eliminated,the limits are pushed further andfurther out, maximizing marginsand increasing the product’s lifeand reliability.

Other uses for HALT chambers

HALT Chambers are the perfecttool for returned products havingfailures that are hard to expose.Returned products are valuablebecause they contain a flaw.Temperature and vibration test-ing in a HALT chamber can oftenfind these failures.

The HASS procedure employedwill vary based on the type ofproduct being tested. HASS isnot just a test, it is a process –each product has its own pro-cess.

Problems uncovered may rangefrom manufacturing mistakes tosupplier quality issues. RootCause Failure Analysis is perfor-med on all failures. If no failuresoccur, the product passes – un -like HALT, HASS is a pass/fail test.

HASS stress levels are less thanthose used in HALT, but aregenerally more severe than anti-cipated in actual service. Thegoal is to use enough stress tofind faults without removing asignificant amount of the pro-duct’s life.

Testing will begin with the HASSprofile determined to be themost effective during the Proofof Screen (POS) process. POS is aprocess showing that a screendoes not damage good hardwareand that the screen is effective infinding the defects present in aproduct.

This consists of running the de si-red HASS process 15 to 30 timesto verify that the screen is notremoving excessive life fromthe product. By performing theproof of screen successfully it isdetermined that the HASS profi-le will not remove more than1/15th of the product’s life.

Common defects revealedthrough HASS may include sol-dering problems, componentfailures, incorrect components,timing problems, IC Processchange, IC Process problem,bent IC leads, electrical toler -ance, mechanical tolerance andraw board problems.

HASS DevelopmentProof of Screen(POS) - 15 Runs

HASS Profile

HALT-HASS Profiles

Examples of typical HASS profiles

The HASS Process

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Galaxy 28/36/44Integrated PneumaticVibration Table andTemperature Test ChamberHALT/HASS System

The Star Galaxy™ HALT/HASSSystems are integrated TestChamber/Vibration Table pack -ages.

The Star Galaxy chambers areequipped with a Liquid Nitrogen(LN2) cooling system, which pro-vides the rapid thermal changerates required to achieve maxi-mum product stress.

The Galaxy system efficientlydelivers high velocity conditio-ned air to the test space forunmatched temperature cyclingperformance.

Our adjustable air flow packageallows the user to redirect andconcentrate airflow to the pro-duct under test for maximumproduct temperature cyclingstress.

Galaxy system rapid thermalchange rates are accomplishedwith smaller space requirements,lower audible noise, no waterrequirement, lower maintenancecosts and greater efficiency thana typical refrigeration system.

The vibration table is a state-of-the-art, six degree-of-freedom(6DoF) tri-axial pneumatic vibra-tion table. A benefit of its paten-ted unique proprietary construc-tion, this vibration table has one

of the most consistent accelera-tion levels per unit area of anytable presently on the market.

The unique control system givesthe user the flexibility to controlvia one accelerometer or anycom bination of four accelero-meters. The “brains” of theGalaxy System is the powerfulStarView Software.

An exclusive diagnostic anddebugging Component ControlOption is available to enhanceeach of the Galaxy models.

Star SeriesTM Galaxy

Function air space system

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Component ControlDiagnostic/DebuggingOption for the GalaxyHALT/HASS Systems

During HALT testing, test engi-neers must perform temperaturestep stress tests on productsuntil failures occur. Certain com-ponents may limit the engineer’sability to test beyond a tempera-ture extreme.

With the dynamic ComponentControl feature, you can keepthese limiting components at anambient temperature in order tocontinue temperature stress steptesting beyond the point wheretesting would normally cease.

The Component Control featureincludes a separate controllerand thermocouple. With stagedheating and a proportional con-trol valve, Component Controlprovides accurate temperaturecontrol to allow testing to conti-nue beyond normal product limi-tations. Flexible ducting allowsthis optional feature to be utili-zed on a wide variety of pro-ducts.

The component control option provides you with a “second chamber”using its own controller, thermocouple, heaters and cooling system. We typically locate the “second chamber” on top of your HALT system.

Star SeriesTM Galaxy

Installation Component Control

Component Control

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Star 28/36/44Pneumatic Vibration Table

The heart of the Star GalaxySystem is the Star pneumaticvibration table which producesquasi-random, six degree-of-freedom (6DoF) – three linear (X,Y, Z) and three angular (roll, pitchand yaw) – vibration accelera-tions in the frequency range of5 Hz to 10 kHz. The table candeliver axis-specific vibrationlevels in a range from 2 gRMS togreater than 60 gRMS.

Due to its patented unique pro-prietary construction, this vibra-tion table produces very con sis -tent acceleration levels per unitarea. The benefit of this is thatmultiple products tested on thetable will all receive almost iden-tical vibration forces, regardless

of where they are mouted to thetable. This is not true of mostother vibration tables.

Table acceleration level can bemonitored and controlled via atri-axial accelerometer block (X,Y and Z axis) or via single Z-axiscontrol. Use of tri-axial control/monitoring provides a muchmore accurate indication of theoverall vibration levels your pro-duct is experiencing, comparedto the Z-axis-only control usedby some manufacturers.

The Star Series tables are equip-ped with an Airfloat™ pneumaticglide system. The table virtuallyfloats when the pneumatic glideis activated, making it very easyto maneuver the table in andout of the chamber. Raising and

lowering the table is so easy youcan literally do it with one finger.Due to his movablity, the tablecan be used independently fromthe chamber.

Star SeriesTM

Function Vibration Table

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Temperature and climatic test systems Series WT/V and WK/V Stress Screening with vibra-tion, temperature and climate

In case of demanding vibrationtests that require temperaturechange rates of up to 25 K/min.or the simulation of climatic con-ditions it is possible to combinethe Star Vibration Table with ourWT/V or WK/V vibration systems.Random vibrations are amongthe most effective methods ofEnvironmental Stress Screening(ESS). Temperature and climatehave an influence on the vibra-tion behaviour of tested materi-als, therefore, both constant andcyclically alternating tempera-tures and climates are of centralimportance for vibration and random tests.

The proven results obtainedfrom the temperature and clima-tic test systems form the basisfor our high quality standard.

For supplying/measuring con-nection to your modules/devicesthermally decoupled entry portsfitted into the chamber side wallscan be utilized.

The test chamber with itsvapourtight welded stainlesssteel container can be turnedinto a fully functional climatictest chamber with the help ofexchangeable floor elements.

The design of our special sealsfor doors, floor elements andvibrator ducts are based on de -cades of experience.

Vibration Test Systems

The optimized airflow, which hasbeen specially developed for thisapplication, ensures rapid tem-perature cycles and a high heatcompensation.

This ensures consistent tempera-ture conditioning for the speci-men along with minimum devia-tions in temperature distribution.

Further information is availablein our brochure on temperatureand climatic test chambers ofseries WT/V and WK/V and onour website www.weiss.info

Effectiveness of different environmental screening methods

Temperature cycling

Random vibration

High temperature

Electrical stress

Thermal shock

Sine vibration, fixed frequency

Low temperature

Sine vibration, sweep frequency

Combined environmental

Mechanical shock

Humidity

Acceleration

Altitude

Weighted Rank

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StarView-SoftwareTemperature and VibrationControl and Analysis

StarView is a user-friendly Micro-soft Windows™-based operatingsystem that provides easy “pointand click“ program writing. Thetest profile is drawn on a graphas the program is written, allo-wing the user to check for errorsas work progresses. Ideal for cre -ating custom HALT tests andHASS Profiles.

Test Chamber Control

The StarView software works inconjunction with a Watlow F4chamber controller to monitorthe air temperature. Used tomo ni tor HALT Hot/Cold StressStep Test. Fourteen additionalthermocouples and Thermo -couple Patch Bridge are inclu-ded with the Star Galaxy Deluxeand Premier Models.

Vibration Table Control

The StarView software also con-trols the repetitive shock shakertable. The vibration gRMS levelcan be driven by the X, Y or Z-axis; or by an average of thethree values. Used to monitorHALT Vibration Stress Step Test.The unique StarView ControlSoftware allows you to controlfrom a single axis or from anaverage of multiple axes. StarGalaxy Deluxe and Premiermodels include one additionalfour-channel vibration systeminput module with cables (cus to-mer to supply additional acceler-ometers).

Auto Spectrum

The vibration waveform is cap-tured and the fast Fourier trans-form applied, resulting in thePSD graph which shows wherethe vibration energy lies in thespectrum. The resonant fre-quency of the Star Galaxy vibra-tion table is tuned to the optimalfrequency range for small elec-tronics components, typicallybetween 900 and 2600 Hz.

Vibration Waveform

A histogram of the accelerationvs. time shows the actual vibra-tion g-levels that were reachedon the table during that period.Peak spikes as high as 10X theindicated g-level can be shownin the histogram.

StarView

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Type Star Galaxy 28 Star Galaxy 36 Star Galaxy 44

Standard Deluxe Premiere Standard Deluxe Premiere Standard Deluxe Premiere

Test space volume ltr. 1230 1680 2330

Temperature range °C -100 to +200 -100 to +200 -100 to +200

Heating / Cooling performance max.K/min. 70 70 70

Vibration table performance (standard)*

Max. gRMS z-axis 60 60 60

Frequency range Hz 5 – 10.000 5 – 10.000 5 – 10.000

Test space dimensions W mm 965 1220 1370

D mm 1145 1295 1370

H mm 1120 1065 1245

Table dimensions W mm 710 915 1120

D mm 710 915 1120

Numbers of pneumatic actuators 8 12 16

Shaker table access height mm 760 760 760

Exterior dimensions W mm 1790 1790 2085 2045 2045 2335 2195 2195 2490

D mm 1475 1475 1475 1625 1625 1625 1700 1700 1700

H mm 2595 2595 3005 2615 2615 3025 3200 3200 3225

Instrument console W mm 610 610 610

exterior dimensions D mm 865 865 865

H mm 1755 1755 1755

Shipping dimensions W mm 2045 2045 2335 2300 2300 2590 2450 2450 2745

chamber D mm 1725 1725 1725 1880 1880 1880 1955 1955 1955

H mm 2775 2775 3180 2795 2795 3200 2995 2995 3405

Shipping weight kg 1800 2090 2250

Power supply requirements 3/N/PE AC 400 V 10 % 50 Hz

Rated power kW 68 90 100

Rated current A 105 135 150

Compressed Air Supply Requirements

Air pressure min. bar 8 8 8

Max. air consumption at max. gRMS l/min 2100 2800 4200

Liquid Nitrogen Supply Requirements

Pressure min. bar 4 4 4

Max. consumption l/min 23 42 53

* Vibration table performance can be increased up to 100 gRMS z-axis

Subject to technical changes. Some devices are illustrated with options.

Technical data

Test systems for professionals. Test the best …

A complete product range for tem-perature and climate testing is avail -able, with test space volumes ofapprox. 34 litres to 2160 litres andworking ranges from –75 to +180 °Cand from 10 to 98 % r.h.In addition, we also offer an exten -sive selection of proven test systemsfor simulating exposure to weather,temperature shock, corrosion andlong-term testing for research, deve-lopment, quality assurance and pro-duction.

As one of the leading manufacturersof simulation systems worldwide,Weiss Umwelttechnik offers the entirerange of high-quality test equipment:from economical series devices towalk-in systems process-integratedsystems built to customer specifi -cation.

A high-performance after-sales ser-vice ensures the optimal support forour customers and high operationalsafety of the systems. Decades ofexperience in the various fields ofapplication and an intensive ex -change of information with our cus -tomers throughout the world all serveto guarantee good co-operation.

If you value know-how, service andall-round safety, ask Weiss Umwelt -technik.

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Weiss Umwelttechnik GmbHSimulationsanlagen Messtechnik35447 Reiskirchen-Lindenstruth / Germany • Greizer Str. 41 –49Telefon +49 6408 84-0 • Telefax +49 6408 84-8710www.weiss.info • E-Mail: [email protected]

www.weiss.infoFurther information, offices in Ger many, sub sidiaries and represen tativesworldwide are avail able at

NEURTEK S.A. T. +34 943 82 00 82 [email protected] www.neurtek.com

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