1、1,TESTING,In the past, qualification testing was performed with the idea being success testing. Requirements were often set to levels as to what a connector can do, not what it should do. It was, and still is by many, considered a costly nuisance.Testing should be viewed (as is gradually becoming so
2、) to determine the functional capability of a design. To determine the susceptibility of a design to common failure mechanisms.,2,TESTING,Traditional testing represents the idea of success testing. Requirements and severity levels where set to what a connector can do as opposed to what it should do.
3、Testing should determine：The functional capability of a design.The susceptibility to common failure mechanisms.,3,TESTING,Testing is intended to demonstrate the capability to meet the “End of Life” criteria for which it is intended. Thus developing a proper test strategy is closely linked to the env
4、ironmental severity levels of the application area involved. Designing a meaningful test strategy requires careful and logical thought just as the creation and development of the product in question.Said strategies must be：Indicative of application field conditions.Demonstrative of the designs capab
5、ility to perform in those environments.,4,TESTING,Testing should be viewed as an extension of the design/product development process. By choosing proper test selection, sequencing and severity levels, testing can:a) be indicative of behavior in the fieldb) demonstrate design capabilityc) be used as
6、a tool in failure analysisd) avoid costly field replacemente) be used as a valuable and useful sales tool,5,TESTING,There are four test programs:Design Verification (DVT)QualificationLong Term Performance TestingReliability Testing (MTBF),6,TESTING-DVT,Design Verification TestingDesign verification
7、tests the product to the performance criteria which is listed in the suppliers literature. May or may not involve sequential testing. Simply verifies that the functional criteria as specified is being adhered to. May be used to screen potential suppliers.Time to perform : 3 to 6 weeks,7,TESTING-Qual
8、ification Testing,Qualification TestingThis is a series of sequential tests which in combination with design requirements will qualify the connector for the specific application involved. The exposures are generally short term in nature. The most common type of qualification testing are military spe
9、cifications.Time to perform: 6 to 10 weeks,8,TESTING-Long Term Performance Testing,Long Term Performance TestingTo establish the long term performance characterization of a connector system. To evaluate its susceptibility or lack thereof to time dependent failure mechanisms. Concentrates on electric
10、al stability and may be application specific. From a user perspective, only need to concentrate on those environments which apply. From a manufacturer point of view, must be broad in scope.Time to perform: 10 to 16weeks,9,TESTING-Reliability Testing,Reliability TestingTo determine MTBF for a given c
11、onnector system. This requires large number of connectors representing full to tolerance range. Large attribute monitoring required (hundreds or thousands of measurements). Exposure times generally in excess of 1000 hours (up to 1560 to 2000 hours). Also requires specific and special statistical ana
12、lysis. Only valid if long term usage is involved and design changes will not occur. Very rarely performed on passive components.Time to perform : 2years,10,TESTING-Test Sequence Guide Lines,Test sequence is the order in which tests, environmental and monitoring tests, are performed. The sequence sho
13、uld be logical and interrelated in order to establish the performance characteristics of the connector in proper perspective. Sample size should be dictated by the number of data points desired. Destructive tests should be performed on samples which are not in specific environmental sequences.Low le
14、vel circuit resistance should not be measured after resistance at rated current. Recommend contact resistance be performed on separate contacts. Each major environment should have its own sequence.,11,TESTING-Test Sequence Guide Lines,All key monitoring tests should be performed immediately after co
15、mpletion of exposure or at specific times not after a series of minor tests. (eq. Dielectric withstanding voltage, insulation resistance, etc.). All unimportant test should be eliminated from the sequences. If required, should be performed on separate units. It is recommended that each environmental
16、 compartment contain cycled and uncycled units. Contacts monitored with voltages 1.0 volts should not be monitored for low level circuit resistance unless said tests are the first and/or last in the sequence.Vibration fixture has to be defined.Test boards as applicable has to be defined.,12,TESTING-
17、Sample size,Sample SizeEach major test compartment should contain a minimum of two connectors and not more than four.Attribute monitoring (LLCR, contact resistance, separation force, etc.).A minimum of 25 data points per connector or 25% of the population whichever is greater. If a connector has les
18、s than 25 positions, all positions should be measured. When multiple row connectors are involved which have different contacts in each row (eq. right angle receptacle connectors), at least 10 contacts per row should be measured.Positions for resistance measurements should include positions at each e
19、nd and in the middle of the contact pattern.DWV, IR, discontinuity monitoring should be performed on separate samples or the LLCR positions should be deleted from the circuits.,13,TESTING-Check,Sanity CheckWhen isolated positions indicate high resistance, measurements should be rechecked. Delete ter
20、mination resistanceFor separation force failures, use dead weight technique. For contact interruptions, breakdown circuit and use more detector channels. Reset detector to determine if transients caused triggering of detector.Good reference test for corrosion: PorosityAbove all, if soldering is invo
21、lved, watch out for flux entrapment and solder wicking.Clean after soldering at least vapor degrease or via ultrasonics.,14,TESTING-Mechanisms,Time dependent mechanisms causing connector malfunction which are gaining in importance are:Fretting CorrosionDiffusion and Intermettalic FormationStress Rel
22、axation (Mech. or Thermal) Degree of Surface CleanlinessWear DebrisIndustrial DustLow Nanosecond EventsMixed Flowing Gas (Corrosion),15,TESTING-Mechanisms,The above are exasperated by:Lower Normal ForceDecreasing Plating ThicknessExpanding ApplicationsLower Circuit Levels,16,TESTING-Environments,The
23、 key environments which can cause signal degradation are:TemperatureHumidityHarsh EnvironmentIndustrial DustCombination of the above,17,TESTING-Environments,The most effective environments are:Cyclic HumidityTemperatureMixed Flowing GasDust (Application Specific)Ineffective or of minor importance:Si
24、ngular Gas (H2S, SO2 , NH3)Steady State Humidity Salt Spray (Except for Shipboard Applications),18,目的-LLCR,低階電路電阻 (Low Level Circuit Resistance)在供應電壓電流而不會改變物理接觸面而且又可檢測到會使電氣特性穩定度惡化的氧化物和薄膜之情況下,評估接觸系統的接觸電阻特性.這項測試會呈現這個性質,接觸系統的電氣特性穩定度是決定於在分析過程中的電阻改變量.這項測試必須依照 EIA 364, TP 23 執行,最大測試電流為 100 mA,最大開路電壓為 20mV
25、.,19,目的-IR & DWV,絕緣電阻 (Insulation Resistance)當直流電位供應於相鄰的接觸點和/或供應於接觸點與最接近的金屬之間時,檢測絕緣物質的電阻.耐電壓 (Dielectric Withstanding Voltage)為了檢測電氣性的連接器在其電壓上升速率中能安全無損的操作而且耐得住因為切換,突然增加或類似情況下所產生的瞬時超額電位.,20,目的-Normal Force,正向力 (Normal Force)測定接觸系統在正常使用的情況下因為任何程度的偏斜而造成的正向力大小,測定永久變形的量和因為應力鬆弛而造成正向力流失的影響,這方面的資料還有這些資料與接觸力
26、之間的關係將使得接觸面的電氣完整性和穩定性做適當的評估,這是接觸系統的一個重要性質之一.,21,目的-Durability,耐久性 (Durability)在平常使用的情況下,接觸面因為插拔會有磨損的情形發生.使用連接器的元件和連接器會有插拔的動作,在設定的環境下,測試連接器的耐久性來評估對電氣特性穩定度的影響.,22,目的-Vibration,振動 (Vibration)測定在設定的階級下是否發生了電路上的不連續.測定當振動的情況發生時,已經套上元件的連接器彼此之間距離的位移量.建立當有外在機械力作用時,連接器系統機械特性的完整性.評估當因為機械力作用而引起在接觸面上的微小變動時,對於整個接
27、觸系統的電氣特性穩定度之影響.,23,目的- Mechanical & Thermal Shock,機械衝擊(Mechanical Shock)檢測連接器的機械和電氣上的完整性.當連接器裝置作用於電子設備時可能會在處理,運輸等情況下受到震動.冷熱衝擊 (Thermal Shock)檢測當連接器暴露於極度高溫和低溫時的電阻,和貯存,運輸,使用在這些輪替的最糟情況下的衝擊.,24,目的-Temperature Life,溫度壽命 (Temperature Life)當暴露於一個會因為溫度改變而使得機械性質失效的高溫環境中,評估這種環境對於電氣穩定性的衝擊,這些環境有:基底金屬和/或底層金屬的接觸表
28、面因為雜質流布或孔隙侵蝕所造成的氧化.貯存於週遭大氣的接觸面中之微細粒子的氧化及/或薄膜形成.因為在基底金屬和/或底層金屬的接觸面沾上了污穢或著暴露於相同的污穢環境中而造成的氧化.因為溫度降低而造成的正向力減少.當使用會遭侵蝕的系統時接觸面的氧化.,25,目的-Thermal Cycling with Humidity,溫濕循環 (Thermal Cycling With Humidity)當暴露於任何會產生高溫/潮濕而使得機械性質失效的環境中,評估這種環境會對接觸系統的電氣穩定性造成的衝擊,這些環境有:因為細微振動所帶起的微塵而引起的侵蝕,溫度的循環引發了接觸面之間的微動,而濕氣加速了氧化的
29、過程.生鏽系統的侵蝕.在接觸面因為引發的微動而造成磨損的物體的氧化.在週遭的大氣環境中貯存於接觸面上或接觸表面間的微小粒子的氧化.藉由在潮濕環境中的氧化過程,檢測因為有微細粒子貯存於接觸面間而造成的電氣穩定性的流失,在接觸面的基底金屬或底層金屬的磨損和生鏽系統的氧化情形.,26,目的-Porosity,孔隙度 (Porosity)為了確認孔洞的大小及因為使用金的末端而在接觸面上展現的不完美.這些不連續的地方在基底金屬或底層金屬會導致侵蝕的現象,接下來這些侵蝕的現象也許會大量的覆蓋於接觸表面上,其他設計性質(如正向力,環境的影響,電路的參數,擦拭,密封效應等)的大小或缺乏這些設計性質會讓侵蝕的現
30、象導致電氣性質的惡化,孔和其他缺點現象的建立將會被視為是一個測試的參考而且在合適的觀點將會被用來評估從不同的機能環境所產生的資料的方法.,27,目的-MFG,混合流動氣體 (Mixed Flowing Gas)混合流動氣體測試是環境測試程序,其最主要的目的是為了評估在模擬貯存或操作的情況下產品的表現.在鍍有金屬的接觸表面上,這些測試也可以用來計算接觸或連接系統上的電氣和耐久性質因鍍膜減量的影響.在測試實驗室,這些規範的測試條件通常選擇模擬有一定代表性的環境或標準金屬表面環境的嚴厲程度的影響.依照以上環境或嚴厲程度而設計的混合流動氣體測試對於評估以下幾種連接器系統項目特別有用:用金或其他貴金屬鍍
31、的表面.為了預防接觸面遭到侵蝕而加於連接器上的外殼及覆蓋物.在上述的環境中,當連接器鍍有金屬的情況下,金屬和金屬間的接觸區域.,28,Normal Force,Normal ForceNormal force requirements are determined by the necessity to maintain the integrity of the contact interface required by the application environment.The normal force of a contact system perpendicular to the c
32、ontact surface. It is the force generated at the contact interface resulting from the dimensional parameter and the deflection level involved.,29,Normal Force,Normal force is interrelated to function characteristics, such as:Durability Levels (Also Wear)Low Level Circuit ResistanceGas TightnessMatin
33、g/Unmating ForceFretting Motion and Corrosion Vibratory Medium Thermal Medium,Thermal ConsiderationsFinish Systems UsedContact GeometryNumber of Contact PointsAmount of Wipe RequiredLong Term StabilityDimensional ConsiderationsStress Levels,30,Permanent Set,Permanent set represents a potential loss
34、of normal force resulting from overstressing the contact. It is influenced by the basic attributes:Yield Strength of the MaterialBeam LengthModulus of ElasticityMaterial ThicknessBoth normal force and permanent set characteristics can be determined by empirical techniques.Permanent set magnitude is
35、determined by experience and empirical testing.,31,Durability,Durability is the number of mating cycles. A connector is expected to undergo.（To simulate the wear normally expected in the life of the connector.）(A) 25xNormal equipment usually specify 50100 for design margins.(B) 100x500xMilitary requ
36、irements.(C) 1000x3000xTest, burn-in and special applications.,32,Durability,KEY monitoring attributes:Mechanical forces.Normal force stabilityElectrical stabilityWearRate of insertion should be limited to 1.0 inch/minute for force measurements and 500 cycles/hr for durability, the latter to prevent
37、 frictional heating problems.Actual mating devices should be used.,33,Mating Force,The force required to fully mating the connector halves together. It is influenced by:Contact Geometry（Pin Tip and Contact configuration）Angle of Attack（Pin Tip and Contact configuration）Number of Positions.Normal For
38、ceFinish（Soft V.S. Hard）Surface Conditions.（Lubricity, Roughness）Caution: In some connectors, mating force is reduced by increasing contact gapes. This reduces normal force, which can result in other problems. Individual engagement force on a single contact is meaningless except for development work
39、.,34,Mating Force,Matting forceTest with actual mating device,Use control speed（1.0 inch/min）Use self centering Feature（X-Y table）Assure self AlignmentTest simulating application such as:Mounted to test boards.Fully wired.Mounted to simulated rack if unsupported.,35,Fretting,FrettingSmall amplitude
40、oscillatory motion, usually tangential, between two solid surfaces in contact.Fretting WearWear arising as a result of fretting. Fretting CorrosionA form of fretting wears in which corrosion plays a significant role.,36,Fretting,Gold surface is not prone to fretting corrosion unless fretting wear oc
41、curs. Fretting Commission will occur only if fretting motion occurs. In most cases fretting wear results in fretting corrosion causing rapidly increasing and erratic resistance.It is dependent on:Vibratory conditions.Thermal excursions.Amount of motion.Normal Force.Material and Surface conditions.Ci
42、rcuit conditions.,37,Fretting,Fretting corrosion is a potential failure mechanism when non noble material are used.Sn on SnBase materials.Au on SnPd Systems (Fictional polymerization),38,Fretting,Long slender contacts more susceptible than Short stubby contacts.Larger amplitudes take longer to devel
43、op failures.Non Nobel finishes and gold flash Pd (alloys) do not perform well if fretting occurs.Gold plating generally not a problem 30 micro inches. However, the thinner the gold, probability of problem increases.Dimpled or edge type contact geometrys result in fretting corrosion faster than conve
44、ntional geometrys.,Rougher surfaces result in fretting corrosion faster than smoother surface (but not super smooth).Remember, for fretting to occur, the environmental dynamics must be greater than the connector force dynamics.Low force large pin out connectors may not fret.High force low pin out connectors may fret.Lubrication will increase significant time before fretting becomes a problem. It will not prevent it.,
