1、II1II1MIL-HDBK-2164A19 June 1996SUPERSEDINGMIL-HDBK-2164(SH)16 January 1996DEPARTMENT OF DEFENSEHANDBOOKENVIRONMENTM-J STRESS SCREENINGPROCESSFORELECTRONIC EQUIPMENTTHIS HANDBOOK IS FOR GUIDANCE ONLY. DO NOT CITE THIS DOCUMENTAS A REQUIREMENT.AMSC NIA AREA RELIProvided by IHSNot for ResaleNo reprodu
2、ction or networking permitted without license from IHS-,-,-,., _. - MIL-HDBK-2164AFOREWORD1. This handbook is approved for use by all Departments and Agenciesof the Department of Defense (DoD)2. This handbook is for guidance only. This handbook cannot becited as a requirement. If it is, the contract
3、or does not have to comply.3. The current emphasis on quality, reliability and hardware designintegrity has resulted in efforts to provide a sound and inherentlyreliable design. The increased complexity and density of packaging ofcontemporary electronic equipment amplifies the ever present problems
4、ofdetecting and correcting latent manufacturing defects. The occurrence of amalfunction incurs extremely high maintenance costs after the equipment hasbeen deployed. It is also important that laboratory testing be extensiveenough to prevent failure that would result in loss of life or mission.4. Thi
5、s handbook provides guidelines that will help in theEnvironmental Strese Screening (ESS) of electronic equipment so that latentdefects may be located and eliminated before the equipment is accepted. Ithas been written in compliance with the DoD Acquisition Reform Initiatives(ARI), Single PrOCeSe Ini
6、tiative (sPI), and the latest series of DoDacquisition directives.5. Beneficial connnents (recommendations, additions, deletionfi) andany pertinent data which may be of use in improving thie document should beaddressed to: Commander, Naval Sea Systems Conmnand, SEA 03R42, 2531Jefferson Davis Highway
7、, l+rlington, VA 22242-5160, by using the self-addressed Standardization Document Improvement Proposal (DD Fonn 1426)appearing at the end of this document or by letter. .iiProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. .MIL-HDBK-2164AcONTENTS . .
8、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1.1 Purpose 1.2 Application to products 1.2.1 Large, heavy items .1.2.2 Contractual responsibility considerations. .2.2.1 General 2.2 Government documents .2.2.1 Specif icat ions, standarda, and handbooks 2.2.
9、2 Other Government documents, drawings, andpublications .2.3 Non-Governm6nt publications 2.4 Order of precedence 3.3.1 Definitions 3.2 Acronyms used in this handbook. 4.4.14.24.2.14.2.1.14.2. 1.24.2.1.34.2 .1.44.2.1.54.2.24.34.3.14.3.24.3.34.44.54.5.14.5.1.14.5.2General Screening conditions .General
10、 environmental guidelines. Standard ambient .Controlled ambient .Thermal screening tolerances .Vibration screening tolerances. Time .Accuracy of screening instrumentation calibration. .Screening facilities .Screening chamber Vibration apparatus Quality of air for supplementary cooled equipment. .Gen
11、eral instrumentation guidelines. Vibration screening guidelines. Screening fixture .Fixture checkout .Control excitation ”.iiiEAGEii111223333444446-777999910 1010101011111112121313Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_. _,MIL-HDBK-2164ACON
12、TENTS4.64.74.7.14.7.24.7.34.8Performance monitoring guidelines. Failure reporting, analysis, and correction actionsystem (FRACAS )Failure during pre defect-free screening. .Failures during defect-free screening. Rescreening .Sampling 5.5.15.1.15.1.1.15.1.25.1.2.15.1.2.1.15.1.2.1.25.1.2.25.1.2.2.15.1
13、.2 .2.25.25.2.15.2.25.2 .2.15.2 .2.25.2.35.2.3.15.2 .3.1.15.2 .3.1.25.2 .3.25.3Environmental stresses. .Random vibration spectrum. Applied axis detemination. .Temperature cycling .Thermal survey Procedure for ambient-cooled equipment. .Procedure for supplementally cooled equipment. .Thermal screenin
14、g .Ambient cooled equipment Supplementally cooled equipment. Total ESS program .Documentation . Individual tests Examination of product. Initial operational test Environmental Screening. Fixed duration pre defect-free (PDF)screening. .Vibration .Thermal cycling .Defect-free (DF) screening Final func
15、tional operational tefit.6. 6.1 Intended use 6.2 Subject term (keyword) listing .1. Screen Development Process. .2. Environmental Stress Screening Constituents. 3. Random Vibration Spectrum. PAGE131313131414141414141517171819191920202020212121212122222222222815ivProvided by IHSNot for ResaleNo repro
16、duction or networking permitted without license from IHS-,-,-4A-1A-I.A-II.c-I.ABcMIL-HDBK-2164A .CONTESTemperature Cycling Profile for Ambient Cooled andSupplementary Cooled Equipment. .ESS Characteristics Curve .Values of PA for Various a and TPDF = TDFProbability of Rejections Due to Random Failur
17、efOr VariOus Values Of ElESSBenefits to Management ESS screening duration, reduced screening andsampling ESS troubleshooting plan. .Navy program management guidance. : PAGE1625282835233032vProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. _MIL-HDBK-2
18、164A1. SCOPE1.1 OlzQcEe. This handbook provides guidelines for EnvironmentalStress Screening (ESS) of electronic equipment, including environmentalscreening conditions, durations of exposure, procedures, equipmentoperation, actions taken upon detection of defects, and screeningdocumentation. These g
19、uidelines provide for a uniform ESS process that maybe utilized for effectively disclosing manufacturing defects in electronicequipment caused by poor workmanship and faulty or marginal parts. It willalso identify design problems if the design is inherently fragile or ifqualification and reliability
20、 growth tests were too benign or notaccomplished. The most common stimuli used in ESS are temperature cyclingand random vibration. A viable ESS prcgram” must be dynamic; the screeningprogram must be actively managed, and tailored to the particularcharacteristics of the equipment being screened. It s
21、hould be noted thatthere are no universal screens applicable to all equipment.ESS is part of a viable engineering development, manufacturing correctiveaction and overhaul process rather than a test in the normal accept/reject8ense. Guidance in developing a screen can be found in figure 1. Thoseparti
22、cipating in the effort, including the contractor should never be ledto believe that a “failure” is bad andwould be held against them. ESS isintended to stimulate defects, not to simulate the operating environment,and therefore, factory failures are encouraged. The root causea of ESSfailures need to
23、be found and corrected before there is a complete process.This handbook cannot be cited as a requirement. If it ia, the contractordoes not have to comply.1.2 The process described herein msy beaPPlied to electronic assemblies, eqUiPment and systems, in six broadcategories as distinguished according
24、to their field service application:1233A3B456Fixed ground equipmentMobile ground vehicle equipmentShipboard equipmenta71 Sheltereda71 ExposedJet aircraft equipmentTurbo-propeller and rotary-wing aircraftEquipmentAir launched weapons and assembledexternal stores1Provided by IHSNot for ResaleNo reprod
25、uction or networking permitted without license from IHS-,-,-.- . .-. . . . - - .MIL-HDBK-2164A “FEEDBACKSTART r II t Ili=l-i=l-lB for example, if an output is observed to be degrading but isstill within specification limits, no replacement or adjustment may bepermitted unless such adjustments are no
26、rmally made manually.1. Failures detected during screening should be counted as if theyoccurred in the defect-free period if the equipment used to monitor theperformance characteristics during the screening was not capable ofdetecting that failure. Refer to figure 2, Notes 1 and 2.4.2.1 Unless other
27、wise specified,measurements and screenings should be made at the conditions in 4.2.1.1through 4.2.1.5.4.2.1.1 Ambient measurement and checks (e.g.,pre- and post-screening) are conducted at room ambient conditions asfollows :Temperature: 250C i 10C (77F i 18F)Relative humidity: Uncontrolled room ambi
28、entAtmospheric prefisure: Uncontrolled site pressure4.2.1.2 Nhen the ambient conditions must beclosely controlled, the following should be maintained:Temperature: 23C f 2C (73F * 3.6F)Relative humidity: 50 percent * 5 percentAtmospheric Pressure: Ideal: 96.45kPa (Range 86.45-162.45)Ideal: 725 mmHg (
29、Range 655-775)Ideal: 28.5 inHg (Range 25.5-30.5)4.2.1.3 The screened item should betotally surrounded by an envelope of air except at necessary supportpoints. The temperature gradient throughout this envelope, which ismeasured close to the screened item, should be within + 2C (*3.6“F) of thescreenin
30、g temperature and not exceed 1C per meter or a maximum of 2.2“Ctotal with equipment nonoperating.9Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. .MIL-HDBK-2164A4.2.1.4 . The acceleration powerspectral density of the screening control signal should
31、 not deviate fromthe specified guidelines by more than *3 d33over the entire test frequencyrange between 20 Hz and 1,000 Hz and should not deviate by more than i6 dBin the screening frequency range between 1,000 and 2,000 Hz. However,deviations of -6 dB in the screening control signal may be granted
32、 forfrequencies greater than 500 Hz due to fixture resonance, screened itemre50nance, or facility limitations. The cumulative bandwidth over which thereductions are allowed cannot be greater than 100 Hz between 500 Hz and1,000 Hz and 300 Hz between 1,000 Hz and 2,000 Hz. In no case should theacceler
33、ation power spectral density be more than -6 dB below the specifiedguidelines No deviation should be granted for frequencies below 500 Hz.Tolerance levels in terms of dB are defined “as:wCU3.1010CJ ,0-.-.!w,whereWI - measured acceleration power spectral density in g2/Hz unitsV/. - specified level in
34、 g2/Hz unitsConfirmation of these tolerances should be made by the use of an analysissystem with the following characteristic:20 to 200 Hz 25 HZ200 to 1000 Hz 50 Hz1000 to 2000 Hz 100 Hz4.2 .1.5 Xi.OE. Elapsed time should be measured with an accuracy of*1 percent.4.2.2 Theaccuracy of instruments and
35、 screening equipment used to control or monitorthe screening parameters should be calibrated in predetermined intervalsand then verified prior to and following each screening. Xi1 instruments.and screening equipment used in conducting the screenings specified hereinshould be calibrated to national s
36、tandards, such as ANSI/NCSL Z540-1.4.3 Screening facilities and apparatus usedin conducting the screenings contained in this handbook should be capableof meeting the conditions specified.4.3.1 The screening chamber should conform tothe following:a. “The screened item should be as recommended ii 4.2.
37、1.3.10Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-2164Ab. The heat source of the screening facility should be so locatedthat radiant heat from the source will not fall directly on the screeneditem.c. Unless otherwise suggested, thermocou
38、ples or equivalenttemperature sensors utilized to determine or control the chambertemperature should be located centrally within the chamber, in the supplyairstream, or in the return airstream, whichever provides the specifiedscreening conditions at the item to be screened. The thermocouples ortempe
39、rature sensors should be baffled or otherwise protected againstradiation effects.d. The conditioned air flow should be suitably baffled to provideuniform air flow around the item. If multiple items are screened, theyshould be so spaced as to provide free circllation between the items andthe chamber
40、walls.4.3.2 . *Y vibration generating machinerycapable of satisfying the random vibration guidelines contained herein isacceptable. The equipment should be capable of maintaining the input asdefined herein throughout the duration of the exposure.4.3.3 Qualdtv of a-ixfor . Thesuccessful implementatio
41、n of the rapid thermal cycle for supplementarycooled equipment is in part dependent upon the close control of certainparameters associated with the cooling air. The two most critical of theseparameters are absolute moisture content and the temperature of the air.As the air temperature ia specified,
42、the only uncontrolled parameter is theabsolute moisture content.The chamber is cycled between -54C and +71oC for moat electronicequipment. As the chamber is programmed to fall below room ambient(approximately +25”C) , the probability of reaching the dew point ofunconditioned, room ambient air is ver
43、y high. This condition is notacceptable as it represents a non-identifiable damage potential whichprovides no benefits in terms of detecting workmanship defects.The air used for supplementary rooling must be temperatureconditioned and dried to the point where its dew point is below -54”C. Ifthis abs
44、olute humidity condition is not met, moisture will condense out ofthe cooling air and remain within the equipment as either free water or icedepending upon the chamber temperature. A closed loop system isrecommended. This system recirculates the same dry air through atemperature conditioning unit in
45、to the equipment.4.4 Instrumentation shouldin accordance with the following guidelines:bea. Real time on line data should be obtained for all criticalperformance parameters.11Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. .MIL-HOBK-2164A .b. Conti
46、nuous permanent records of all environmental screeningconditions should be provided.c. Transducer installation should be in accordance with thefollowing:(1) Location should be selected to permitof the screened article envronment.(2) The transducer characteristics shouldscreened article.accurate meas
47、urementnot affect the(3) Control accelerometers should be mounted mechanically.(4) Response accelerometer attachment methods should becompatible with the maximum levels and frequencies expected during thescreening.d. ml instrumentation should be calibrated prior to supplying powerto environmental sc
48、reening equipment.e. To permit as complete an evaluation as possible of specificscreened item performance under the various specified screening conditions,I all relevant critical screening signals should be recorded. This willpermit post-screening analysis to supplement the real-time monitoring andc
49、an allow the accumulation of trend data on critical screening parameters.f. Screening records should be maintained for the screened item.All discrepancies, including those attributed to screening equipment, inputpower, and procedural errors, including their disposition, should beincluded in the records.4.5 . . . The following guidelines,tolerances and data handling te
