Laptop Test Conditions
Notebook computer from the early 12-inch screen evolution to the current LED backlit screen, its computing efficiency and 3D processing, will not be lost to the general desktop computer, and the weight is becoming less and less burden, the relative reliability test requirements for the entire notebook computer is becoming more and more stringent, from the early packaging to the current boot down, the traditional high temperature and high humidity to the current condensation test. From the temperature and humidity range of the general environment to the desert test as a common condition, these are the parts that need to be considered in the production of notebook computer related components and design, the test conditions of the relevant environmental tests collected so far are organized and shared with you.
Keyboard tapping test:
Test one:
GB:1 million times
Key pressure :0.3~0.8(N)
Button stroke :0.3~1.5(mm)
Test 2: Key pressure: 75g(±10g) Test 10 keys for 14 days, 240 times per minute, a total of about 4.83 million times, once every 1 million times
Japanese manufacturers :2 to 5 million times
Taiwan manufacturer 1: more than 8 million times
Taiwan Manufacturer 2:10 million times
Power switch and connector plug pull test:
This test model simulates the lateral forces that each connector can withstand under abnormal usage. General laptop test items: USB, 1394, PS2, RJ45, Modem, VGA... Equal application force 5kg(50 times), up and down left and right pull and plug.
Power switch and connector plug test:
4000 times (Power supply)
Screen cover opening and closing test:
Taiwanese manufacturers: open and close 20,000 times
Japanese manufacturer 1: opening and closing test 85,000 times
Japanese manufacturer 2: opening and closing 30,000 times
System standby and recovery switch test:
General note type: interval 10sec, 1000cycles
Japanese manufacturer: System standby and recovery switch test 2000 times
Common causes of laptop failure:
☆ Foreign objects fall on the notebook
☆ Falls off the table while in use
☆ Tuck the notebook in a handbag or trolley case
☆ Extremely high temperature or low temperature ☆ Normal use (overuse)
☆ Wrong use in tourist destinations
☆PCMCIA inserted incorrectly
☆ Place foreign objects on the keyboard
Shutdown drop test:
General notebook type :76 cm
GB package drop: 100cm
Us Army and Japanese notebook computers: The height of the computer is 90 cm from all sides, sides, corners, a total of 26 sides
Platform :74 cm (packing required)
Land: 90cm (packing required)
TOSHIBA&BENQ 100 cm
Boot drop test:
Japanese :10 cm boot fall
Taiwan :74 cm boot fall
Laptop main board temperature shock:
Slope 20℃/min
Number of cycles 50cycles(no operation during impact)
The U.S. military's technical standards and test conditions for laptop procurement are as follows:
Impact test: Drop the computer 26 times from all sides, sides and corners at a height of 90 cm
Earthquake resistance test :20Hz~1000Hz, 1000Hz~2000Hz frequency once an hour X, Y and Z axis continuous vibration
Temperature test :0℃~60℃ 72 hours of aging oven
Waterproof test: Spray water on the computer for 10 minutes in all directions, and the water spray rate is 1mm per minute
Dust test: Spray the concentration of 60,000 mg/ per cubic meter of dust for 2 seconds (interval of 10 minutes, 10 consecutive times, time 1 hour)
Meets MIL-STD-810 military specifications
Waterproof test:
Us Army notebook :protection class:IP54(dust & rain) Sprayed the computer with water in all directions for 10 minutes at a rate of 1mm per minute.
Dust proof test:
Us Army notebook: Spray a concentration of 60,000 mg/ m3 of dust for 2 seconds (10 minute intervals, 10 consecutive times, time 1 hour)
Temperature and Humidity Terms
Dew Point temperature Td, in the air water vapor content unchanged, maintain a certain pressure, so that the air cooling to reach saturation temperature called dew point temperature, referred to as dew point, the unit is expressed in ° C or ℉. It's actually the temperature at which water vapor and water are in equilibrium. The difference between the actual temperature (t) and the dew point temperature (Td) indicates how far the air is saturated. When t>Td, it means that the air is not saturated, when t=Td, it is saturated, and when t<Td, it is supersaturated.
dew is the liquid water in the air that condenses on the ground. In the evening or at night, due to the radiation cooling of the ground or ground objects, the air layer close to the surface will also cool down. When the temperature drops below the dew point, that is, when the water vapor content in the air is susaturated, there will be condensation of water vapor on the surface of the ground or ground objects. If the dew point temperature is above 0 ° C at this time, tiny water droplets appear on the ground or ground objects, which are called dew.
frost refers to the white ice crystals formed on the ground or objects after the air close to the ground is cooled to the frost point (meaning the dew point is below 0) under the influence of radiation cooling on the ground.
fog refers to the condensation of water vapor suspended in the atmosphere near the Earth's surface, composed of small water droplets or ice crystals. When the temperature reaches the dew point temperature (or is close to the dew point), the water vapor in the air condenses to form fog.
snow is solid water in the form of snowflakes that falls to the ground from mixed clouds. Precipitation consisting of a large number of white opaque ice crystals (snow crystals) and their polymers (snow masses). Snow is the natural phenomenon of water condensing and falling in the air, or falling snow;
There is a limit to the amount of water vapor that can be contained in a unit volume of air under a certain pressure and a certain temperature. If the water vapor contained in the volume of air exceeds this limit, the water vapor will condense and produce precipitation, and the actual value of water vapor in the volume of air. In terms of absolute humidity. The more water vapor there is, the higher the absolute humidity of the air.
Relative Humidity refers to the percentage of water vapor pressure in the air and saturated water vapor pressure at the same temperature, or the ratio of the absolute humidity of wet air to the maximum absolute humidity that can be reached at the same temperature, and can also be expressed as the ratio of the partial pressure of water vapor in wet air to the saturation pressure of water at the same temperature.
Humidity: wet and dry bulb measurement
The dry and wet bulb thermometer is used to detect the [relative humidity] in the air, the dry bulb temperature is the temperature measured by the general temperature sensor, and the wet bulb temperature is tied on the temperature sensor with a wet cloth, and then soaked in a small cup of water, so that the water is wrapped in the whole sensor, because the relative humidity in the air must be less than or equal to 100% (the water vapor in the air is not saturated). Therefore, the moisture of the wet bulb will be evaporated, and the heat will be taken away during evaporation, resulting in a drop in the wet bulb temperature (the dry bulb temperature is the real air temperature), which means that the greater the difference in the readings of the dry and wet bulb thermometer, the more vigorous the evaporation of water, and the smaller the relative humidity in the air, as long as the temperature of the dry and wet bulb is measured, Then compare [relative humidity table] you can know the relative humidity of the environment at that time.
Conduction Zone of Heat
Thermal conductivity
It is the thermal conductivity of a substance, passing from high temperature to low temperature within the same substance. Also known as: thermal conductivity, thermal conductivity, thermal conductivity, heat transfer coefficient, heat transfer, thermal conductivity, thermal conductivity, thermal conductivity, thermal conductivity.
Thermal conductivity formula
k = (Q/t) *L/(A*T) k: thermal conductivity, Q: heat, t: time, L: length, A: area, T: temperature difference in SI units, the unit of thermal conductivity is W/(m*K), in imperial units, is Btu · ft/(h · ft2 · °F)
Heat transfer coefficient
In thermodynamics, mechanical engineering and chemical engineering, the heat conductivity is used to calculate the heat conduction, mainly the heat conduction of convection or the phase transformation between fluid and solid, which is defined as the heat through the unit area per unit time under the unit temperature difference, called the heat conduction coefficient of the substance, if the thickness of the mass of L, the measurement value to be multiplied by L, The resulting value is the coefficient of thermal conductivity, usually denoted as k.
Unit conversion of heat conduction coefficient
1 (CAL) = 4.186 (j), 1 (CAL/s) = 4.186 (j/s) = 4.186 (W).
The impact of high temperature on electronic products:
The rise in temperature will cause the resistance value of the resistor to decrease, but also shorten the service life of the capacitor, in addition, the high temperature will cause the transformer, the performance of the related insulation materials to decrease, the temperature is too high will also cause the solder joint alloy structure on the PCB board to change: IMC thickens, solder joints become brittle, tin whisker increases, mechanical strength decreases, junction temperature increases, the current amplification ratio of transistor increases rapidly, resulting in collector current increases, junction temperature further increases, and finally component failure.
Explanation of proper terms:
Junction Temperature: The actual temperature of a semiconductor in an electronic device. In operation, it is usually higher than the Case Temperature of the package, and the temperature difference is equal to the heat flow multiplied by the thermal resistance. Free convection (natural convection) : Radiation (radiation) : Forced Air(gas cooling) : Forced Liquid (gas cooling) : Liquid Evaporation: Surface Surroundings Surroundings
Common simple considerations for thermal design:
1 Simple and reliable cooling methods such as heat conduction, natural convection and radiation should be used to reduce costs and failures.
2 Shorten the heat transfer path as much as possible, and increase the heat exchange area.
3 When installing components, the influence of radiation heat exchange of peripheral components should be fully considered, and the thermal sensitive devices should be kept away from the heat source or find a way to use the protective measures of the heat shield to isolate the components from the heat source.
4 There should be sufficient distance between the air inlet and the exhaust port to avoid hot air reflux.
5 The temperature difference between the incoming air and the outgoing air should be less than 14 ° C.
6 It should be noted that the direction of forced ventilation and natural ventilation should be consistent as far as possible.
7 Devices with large heat should be installed as close as possible to the surface that is easy to dissipate heat (such as the inner surface of the metal casing, metal base and metal bracket, etc.), and there is good contact heat conduction between the surface.
8 Power supply part of the high-power tube and rectifier bridge pile belong to the heating device, it is best to install directly on the housing to increase the heat dissipation area. In the layout of the printed board, more copper layers should be left on the board surface around the larger power transistor to improve the heat dissipation capacity of the bottom plate.
9 When using free convection, avoid using heat sinks that are too dense.
10 The thermal design should be considered to ensure that the current carrying capacity of the wire, the diameter of the selected wire must be suitable for the conduction of the current, without causing more than the allowable temperature rise and pressure drop.
11 If the heat distribution is uniform, the spacing of the components should be uniform to make the wind flow evenly through each heat source.
12 When using forced convection cooling (fans), place the temperature-sensitive components closest to the air intake.
13 The use of free convection cooling equipment to avoid arranging other parts above the high power consumption parts, the correct approach should be uneven horizontal arrangement.
14 If the heat distribution is not uniform, the components should be sparsely arranged in the area with large heat generation, and the component layout in the area with small heat generation should be slightly denser, or add a diversion bar, so that the wind energy can effectively flow to the key heating devices.
15 The structural design principle of the air inlet: on the one hand, try to minimize its resistance to the air flow, on the other hand, consider dust prevention, and comprehensively consider the impact of the two.
16 Power consumption components should be spaced as far apart as possible.
17 Avoid crowding temperature sensitive parts together or arranging them next to high power consuming parts or hot spots.
18 The use of free convection cooling equipment to avoid arranging other parts above the high power consumption parts, the correct practice should be uneven horizontal arrangement.
Temperature Cyclic Stress Screening (1)
Environmental Stress Screening (ESS)
Stress screening is the use of acceleration techniques and environmental stress under the design strength limit, such as: burn in, temperature cycling, random vibration, power cycle... By accelerating the stress, the potential defects in the product emerge [potential parts material defects, design defects, process defects, process defects], and eliminate electronic or mechanical residual stress, as well as eliminate stray capacitors between multi-layer circuit boards, the early death stage of the product in the bath curve is removed and repaired in advance, so that the product through moderate screening, Save the normal period and decline period of the bathtub curve to avoid the product in the process of use, the test of environmental stress sometimes lead to failure, resulting in unnecessary losses. Although the use of ESS stress screening will increase the cost and time, for improving the product delivery yield and reduce the number of repairs, there is a significant effect, but for the total cost will be reduced. In addition, customer trust will also be improved, generally for electronic parts of the stress screening methods are pre-burning, temperature cycle, high temperature, low temperature, PCB printed circuit board stress screening method is temperature cycle, for the electronic cost of the stress screening is: Power pre-burning, temperature cycling, random vibration, in addition to the stress screen itself is a process stage, rather than a test, screening is 100% of the product procedure.
Stress screening applicable product stage: R & D stage, mass production stage, before delivery (screening test can be carried out in components, devices, connectors and other products or the whole machine system, according to different requirements can have different screening stress)
Stress screening comparison:
a. Constant high temperature pre-burning (Burn in) stress screening, is the current electronic IT industry commonly used method to precipitate electronic components defects, but this method is not suitable for screening parts (PCB, IC, resistor, capacitor), According to statistics, the number of companies in the United States that use temperature cycling to screen parts is five times more than the number of companies that use constant high temperature prefiring to screen components.
B. GJB/DZ34 indicates the proportion of temperature cycle and random vibrating screen selection defects, temperature accounted for about 80%, vibration accounted for about 20% of the defects in various products.
c. The United States has conducted a survey of 42 enterprises, random vibration stress can screen out 15 to 25% of the defects, while the temperature cycle can screen out 75 to 85%, if the combination of the two can reach 90%.
d. The proportion of product defect types detected by temperature cycling: insufficient design margin: 5%, production and workmanship errors: 33%, defective parts: 62%
Description of fault induction of temperature cyclic stress screening:
The cause of product failure induced by temperature cycling is: when the temperature is cycled within the upper and lower extremal temperatures, the product produces alternating expansion and contraction, resulting in thermal stress and strain in the product. If there is a transient thermal ladder (temperature non-uniformity) within the product, or the thermal expansion coefficients of adjacent materials within the product do not match each other, these thermal stresses and strains will be more drastic. This stress and strain is greatest at the defect, and this cycle causes the defect to grow so large that it can eventually cause structural failure and generate electrical failure. For example, a cracked electroplated through-hole eventually cracks completely around it, causing an open circuit. Thermal cycling enables soldering and plating through holes on printed circuit boards... Temperature cyclic stress screening is especially suitable for electronic products with printed circuit board structure.
The fault mode triggered by the temperature cycle or the impact on the product is as follows:
a. The expansion of various microscopic cracks in the coating, material or wire
b. Loosen poorly bonded joints
c. Loosen improperly connected or riveted joints
d. Relax the pressed fittings with insufficient mechanical tension
e. Increase the contact resistance of poor quality solder joints or cause an open circuit
f. Particle, chemical pollution
g. Seal failure
h. Packaging issues, such as bonding of protective coatings
i. Short circuit or open circuit of the transformer and coil
j. The potentiometer is defective
k. Poor connection of welding and welding points
l. Cold welding contact
m. Multi-layer board due to improper handling of open circuit, short circuit
n. Short circuit of power transistor
o. Capacitor, transistor bad
p. Dual row integrated circuit failure
q. A box or cable that is nearly short-circuited due to damage or improper assembly
r. Breakage, breakage, scoring of material due to improper handling... Etc.
s. out-of-tolerance parts and materials
t. resistor ruptured due to lack of synthetic rubber buffer coating
u. The transistor hair is involved in the grounding of the metal strip
v. Mica insulation gasket rupture, resulting in short circuit transistor
w. Improper fixing of the metal plate of the regulating coil leads to irregular output
x. The bipolar vacuum tube is open internally at low temperature
y. Coil indirect short circuit
z. Ungrounded terminals
a1. Component parameter drift
a2. Components are improperly installed
a3. Misused components
a4. Seal failure
Introduction of stress parameters for temperature cyclic stress screening:
The stress parameters of temperature cyclic stress screening mainly include the following: high and low temperature extremum range, dwell time, temperature variability, cycle number
High and low temperature extremal range: the larger the range of high and low temperature extremal, the fewer cycles required, the lower the cost, but can not exceed the product can withstand the limit, do not cause new fault principle, the difference between the upper and lower limits of temperature change is not less than 88°C, the typical range of change is -54°C to 55°C.
Dwell time: In addition, the dwell time can not be too short, otherwise it is too late to make the product under test produce thermal expansion and contraction stress changes, as for the dwell time, the dwell time of different products is different, you can refer to the relevant specification requirements.
Number of cycles: As for the number of cycles of temperature cyclic stress screening, it is also determined by considering product characteristics, complexity, upper and lower limits of temperature and screening rate, and the screening number should not be exceeded, otherwise it will cause unnecessary harm to the product and cannot improve the screening rate. The number of temperature cycles ranges from 1 to 10 cycles [ordinary screening, primary screening] to 20 to 60 cycles [precision screening, secondary screening], for the removal of the most likely workmanship defects, about 6 to 10 cycles can be effectively removed, in addition to the effectiveness of the temperature cycle, Mainly depends on the temperature variation of the product surface, rather than the temperature variation inside the test box.
There are seven main influencing parameters of temperature cycle:
(1) Temperature Range
(2) Number of Cycles
(3) Temperature Rate of Chang
(4) Dwell Time
(5) Airflow Velocities
(6) Uniformity of Stress
(7) Function test or not (Product Operating Condition)
AEC-Q100- Failure Mechanism Based on Integrated Circuit Stress Test Certification
With the progress of automotive electronic technology, there are many complicated data management control systems in today's cars, and through many independent circuits, to transmit the required signals between each module, the system inside the car is like the "master-slave architecture" of the computer network, in the main control unit and each peripheral module, automotive electronic parts are divided into three categories. Including IC, discrete semiconductor, passive components three categories, in order to ensure that these automotive electronic components meet the highest standards of automotive anquan, the American Automotive Electronics Association (AEC, The Automotive Electronics Council is a set of standards [AEC-Q100] designed for active parts [microcontrollers and integrated circuits...] and [[AEC-Q200] designed for passive components, which specifies the product quality and reliability that must be achieved for passive parts. Aec-q100 is the vehicle reliability test standard formulated by the AEC organization, which is an important entry for 3C and IC manufacturers into the international auto factory module, and also an important technology to improve the reliability quality of Taiwan IC. In addition, the international auto factory has passed the anquan standard (ISO-26262). AEC-Q100 is the basic requirement to pass this standard.
List of automotive electronic parts required to pass AECQ-100:
Automotive disposable memory, Power Supply step-down regulator, Automotive photocoupler, three-axis accelerometer sensor, video jiema device, rectifier, ambient light sensor, non-volatile ferroelectric memory, power management IC, embedded flash memory, DC/DC regulator, Vehicle gauge network communication device, LCD driver IC, Single power Supply differential Amplifier, Capacitive proximity switch Off, high brightness LED driver, asynchronous switcher, 600V IC, GPS IC, ADAS Advanced Driver Assistance System Chip, GNSS Receiver, GNSS front-end amplifier... Let's wait.
AEC-Q100 Categories and Tests:
Description: AEC-Q100 specification 7 major categories a total of 41 tests
Group A- ACCELERATED ENVIRONMENT STRESS TESTS consists of 6 tests: PC, THB, HAST, AC, UHST, TH, TC, PTC, HTSL
Group B- ACCELERATED LIFETIME SIMULATION TESTS consists of three tests: HTOL, ELFR, and EDR
PACKAGE ASSEMBLY INTEGRITY TESTS consists of 6 tests: WBS, WBP, SD, PD, SBS, LI
Group D- DIE FABRICATION RELIABILITY Test consists of 5 TESTS: EM, TDDB, HCI, NBTI, SM
The group ELECTRICAL VERIFICATION TESTS consist of 11 tests, including TEST, FG, HBM/MM, CDM, LU, ED, CHAR, GL, EMC, SC and SER
Cluster F-Defect SCREENING TESTS: 11 tests, including: PAT, SBA
The CAVITY PACKAGE INTEGRITY TESTS consist of 8 tests, including: MS, VFV, CA, GFL, DROP, LT, DS, IWV
Short description of test items:
AC: Pressure cooker
CA: constant acceleration
CDM: electrostatic discharge charged device mode
CHAR: indicates the feature description
DROP: The package falls
DS: chip shear test
ED: Electrical distribution
EDR: non-failure-prone storage durability, data retention, working life
ELFR: Early life failure rate
EM: electromigration
EMC: Electromagnetic compatibility
FG: fault level
GFL: Coarse/fine air leakage test
GL: Gate leakage caused by thermoelectric effect
HBM: indicates the human mode of electrostatic discharge
HTSL: High temperature storage life
HTOL: High temperature working life
HCL: hot carrier injection effect
IWV: Internal hygroscopic test
LI: Pin integrity
LT: Cover plate torque test
LU: Latching effect
MM: indicates the mechanical mode of electrostatic discharge
MS: Mechanical shock
NBTI: rich bias temperature instability
PAT: Process average test
PC: Preprocessing
PD: physical size
PTC: power temperature cycle
SBA: Statistical yield analysis
SBS: tin ball shearing
SC: Short circuit feature
SD: weldability
SER: Soft error rate
SM: Stress migration
TC: temperature cycle
TDDB: Time through dielectric breakdown
TEST: Function parameters before and after stress test
TH: damp and heat without bias
THB, HAST: Temperature, humidity or high accelerated stress tests with applied bias
UHST: High acceleration stress test without bias
VFV: random vibration
WBS: welding wire cutting
WBP: welding wire tension
Temperature and humidity test conditions finishing:
THB(temperature and humidity with applied bias, according to JESD22 A101) : 85℃/85%R.H./1000h/bias
HAST(High Accelerated stress test according to JESD22 A110) : 130℃/85%R.H./96h/bias, 110℃/85%R.H./264h/bias
AC pressure cooker, according to JEDS22-A102:121 ℃/100%R.H./96h
UHST High acceleration stress test without bias, according to JEDS22-A118, equipment: HAST-S) : 110℃/85%R.H./264h
TH no bias damp heat, according to JEDS22-A101, equipment: THS) : 85℃/85%R.H./1000h
TC(temperature cycle, according to JEDS22-A104, equipment: TSK, TC) :
Level 0: -50℃←→150℃/2000cycles
Level 1: -50℃←→150℃/1000cycles
Level 2: -50℃←→150℃/500cycles
Level 3: -50℃←→125℃/500cycles
Level 4: -10℃←→105℃/500cycles
PTC(power temperature cycle, according to JEDS22-A105, equipment: TSK) :
Level 0: -40℃←→150℃/1000cycles
Level 1: -65℃←→125℃/1000cycles
Level 2 to 4: -65℃←→105℃/500cycles
HTSL(High temperature storage life, JEDS22-A103, device: OVEN) :
Plastic package parts: Grade 0:150 ℃/2000h
Grade 1:150 ℃/1000h
Grade 2 to 4:125 ℃/1000h or 150℃/5000h
Ceramic package parts: 200℃/72h
HTOL(High temperature working life, JEDS22-A108, equipment: OVEN) :
Grade 0:150 ℃/1000h
Class 1:150℃/408h or 125℃/1000h
Grade 2:125℃/408h or 105℃/1000h
Grade 3:105℃/408h or 85℃/1000h
Class 4:90℃/408h or 70℃/1000h
ELFR(Early Life failure Rate, AEC-Q100-008) : Devices that pass this stress test can be used for other stress tests, general data can be used, and tests before and after ELFR are performed under mild and high temperature conditions.
Test de rupture transitoire du cycle de température de la plaque VMRLe test de cycle de température est l'une des méthodes les plus couramment utilisées pour tester la fiabilité et la durée de vie des matériaux de soudage sans plomb et des pièces CMS. Il évalue les pièces adhésives et les joints de soudure sur la surface des CMS et provoque une déformation plastique et une fatigue mécanique des matériaux des joints de soudure sous l'effet de fatigue du cycle de température froide et chaude avec une variabilité de température contrôlée, afin de comprendre les dangers potentiels et les facteurs de défaillance. de joints de soudure et CMS. Le diagramme en guirlande est connecté entre les pièces et les joints de soudure. Le processus de test détecte les coupures et les coupures entre les lignes, les pièces et les joints de soudure grâce au système de mesure de rupture instantanée à grande vitesse, qui répond à la demande de test de fiabilité des connexions électriques pour évaluer si les joints de soudure, les billes d'étain et les pièces tombent en panne. Ce test n'est pas vraiment simulé. Son objectif est d'appliquer des contraintes sévères et d'accélérer le facteur de vieillissement sur l'objet à tester pour confirmer si le produit est conçu ou fabriqué correctement, puis d'évaluer la durée de vie en fatigue thermique des joints de soudure des composants. Le test de fiabilité de la connexion électrique à coupure instantanée à grande vitesse est devenu un maillon clé pour assurer le fonctionnement normal du système électronique et éviter la défaillance de la connexion électrique causée par la défaillance du système immature. Les changements de résistance sur une courte période de temps ont été observés lors de changements accélérés de température et d’essais de vibration.But:1. S'assurer que les produits conçus, fabriqués et assemblés répondent aux exigences prédéterminées2. Relaxation de la contrainte de fluage des joints de soudure et de la rupture de rupture CMS causée par la différence de dilatation thermique3. La température maximale de test du cycle de température doit être inférieure de 25 ℃ à la température Tg du matériau PCB, afin d'éviter plus d'un mécanisme d'endommagement du produit de test de remplacement.4. La variabilité de la température à 20 ℃/min est un cycle de température, et la variabilité de la température au-dessus de 20 ℃/min est un choc thermique.5. L'intervalle de mesure dynamique du joint de soudage ne dépasse pas 1 min6. Le temps de séjour à haute et basse température pour la détermination des défaillances doit être mesuré en 5 coups.Exigences:1. Le temps de température total du produit testé se situe dans la plage de la température maximale nominale et de la température minimale, et la durée du temps de séjour est très importante pour le test accéléré, car le temps de séjour n'est pas suffisant pendant le test accéléré. , ce qui rendra le processus de fluage incomplet2. La température du résident doit être supérieure à la température Tmax et inférieure à la température Tmin.Se référer à la liste des spécifications :IPC-9701, IPC650-2.6.26, IPC-SM-785, IPCD-279, J-STD-001, J-STD-002, J-STD-003, JESD22-A104, JESD22-B111, JESD22-B113, JESD22-B117 , SJR-01
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