The Role of High and Low Temperature Test Chamber for Electronic Component Testing
High and low temperature test chamber is used for electronic and electrical components, automation parts, communication components, automotive parts, metal, chemical materials, plastics and other industries, national defense industry, aerospace, military, BGA, PCB substrate wrench, electronic chip IC, semiconductor ceramic magnetic and polymer material physical changes. Testing the performance of its material to withstand high and low temperatures and the chemical changes or physical damage of the product in thermal expansion and contraction can confirm the quality of the product, from precision ics to heavy machinery components, will be an essential test chamber for product testing in various fields.
What can the high and low temperature test chamber do for electronic components? Electronic components are the foundation of the whole machine and may cause time - or stress-related failures during use due to their inherent defects or improper control of the manufacturing process. To ensure the reliability of the entire batch of components and meet the requirements of the entire system, you need to exclude the components that may have initial faults under operating conditions.
1. High temperature storage
The failure of electronic components is mostly caused by various physical and chemical changes in the body and surface, which are closely related to temperature. After the temperature rises, the chemical reaction speed is greatly accelerated, accelerating the failure process. The defective components can be exposed in time and eliminated.
High temperature screening is widely used in semiconductor devices, which can effectively eliminate failure mechanisms such as surface contamination, poor bonding and oxide layer defects. Generally stored at the highest junction temperature for 24 to 168 hours. High temperature screening is simple, inexpensive and can be carried out on many parts. After high temperature storage, the parameter performance of components can be stabilized and the parameter drift in use can be reduced.
2. Power test
In the screening, under the combined action of thermoelectric stress, many potential defects of the body and surface of the component can be well exposed, which is an important project of reliability screening. Various electronic components are usually refined for a few hours to 168 hours under rated power conditions. Some products, such as integrated circuits, can not arbitrarily change the conditions, but can use high temperature working mode to increase the working junction temperature to achieve a high stress state. Power refining requires special test equipment, high and low temperature test chamber, high cost, screening time should not be too long. Civilian products are usually a few hours, military high-reliability products can choose 100,168 hours, and aviation-grade components can choose 240 hours or longer.
3. Temperature cycle
Electronic products will encounter different ambient temperature conditions during use. Under the stress of thermal expansion and contraction, components with poor thermal matching performance are easy to fail. Temperature cycle screening utilizes the thermal expansion and contraction stress between extreme high temperature and extreme low temperature to effectively eliminate products with thermal performance defects. The commonly used component screening conditions are -55~125℃, 5~10 cycles.
Power refining requires special test equipment, high cost, screening time should not be too long. Civilian products are usually a few hours, military high-reliability products can choose 100,168 hours, and aviation-grade components can choose 240 hours or longer.
4. The necessity of screening components
The inherent reliability of electronic components depends on the reliability design of the product. In the manufacturing process of the product, due to human factors or fluctuations in raw materials, process conditions, and equipment conditions, the final product can not all achieve the expected inherent reliability. In every batch of finished products, there are always some products with some potential defects and weaknesses, which are characterized by early failure under certain stress conditions. The average life of early failed parts is much shorter than normal products.
Whether electronic equipment can work reliably depends on whether electronic components can work reliably. If the early failure parts are installed together with the whole machine equipment, the failure rate of the early failure of the whole machine equipment will be greatly increased, and its reliability will not meet the requirements, and it will also pay a huge price to repair.
Therefore, whether it is a military product or a civilian product, screening is an important means to ensure reliability. High and low temperature test chamber is the best choice for the environmental reliability test of electronic components.
Maintenance Method of High and Low Temperature Test Chamber
There are three common types of high and low temperature test chamber controllers: software failure, system failure and hardware failure.
1, Software failure:
Software failure mainly refers to the controller failure of the high and low temperature test chamber, including the internal parameters, the control point IS control and output signal of the solenoid valve on and off.
2, System failure:
System failure refers to the initial design problems of the refrigeration system, including the leakage of refrigerant caused by high and low temperature test chamber does not cool down, and refrigerant leakage is often due to transport and high and low temperature test chamber operation jitter or refrigeration copper pipe welding process is not fine and other reasons caused.
3, Hardware failure:
Hardware failure may lead to non-cooling hardware compressor, solenoid valve and other refrigeration components.
Then the user can listen and touch to roughly understand what is the hardware high and low temperature test chamber damage, if it is a compressor failure, the compressor sound will be abnormal or do not work does not start or the compressor itself temperature is much higher than usual temperature, and the solenoid valve failure and other refrigeration components failure users are not too good to master.
In addition, the damage of the controller and the damage of the electronic parts of the control refrigeration system may also cause the phenomenon of non-cooling and non-cooling of the high and low temperature test chamber.
Scientific principle of heating and cooling of high and low temperature test chamber:
The high and low temperature test chamber has the functions of heating, cooling, humidification and dehumidification, and can detect the product's high temperature resistance, low temperature resistance and humidity resistance. How is the temperature in the high and low temperature test chamber controlled?
The heating device is the key link to control whether the high and low temperature test chamber is heated up. The controller outputs voltage to the relay when it gets the heating instruction. The high and low temperature test chamber is about 3-12 volts of direct current added to the solid state relay. The AC end of the high and low temperature test chamber is equivalent to a wire connection, and the contactor is also drawn at the same time. Heat up the constant temperature and humidity test chamber.
Cooling is an important part of the high and low temperature test chamber, which directly affects the determination of a high and low temperature and performance, including compressor, condenser, throttling device, evaporator four major components, compressor is the heart of the refrigeration system, it inhales low temperature and low pressure gas, into high temperature and high pressure gas, through condensation into a liquid to release heat, through the fan to take away heat, Therefore, the test chamber is the reason of hot air, and then become low pressure liquid through throttling, and then become low temperature and low pressure gas through the evaporator back to the compressor, the refrigerant in the evaporator to absorb the heat of the high and low temperature chamber to complete the gasification process and absorb heat, to achieve the purpose of refrigeration, to complete the high and low temperature test chamber cooling process.
High and low temperature chamber temperature and cooling rate test procedure:
In the adjustable range of the temperature of the test chamber, the lowest nominal temperature was selected as the lowest cooling temperature, and the highest nominal temperature was selected as the highest heating temperature.
Open the cold source, so that the test chamber from room temperature to the lowest cooling temperature, stable for at least 3 hours, rise to the highest heating temperature, stable for at least 3 hours and then to the lowest cooling temperature, during the heating and cooling, record once a minute, until the end of the test process.
The principle of high and low temperature test chamber heating and cooling is so, the realization of its function is completed by the setting of the control system, understanding the principle of heating and cooling, in the use of high and low temperature test chamber must be more handy.
Definition and Use of Temperature Cycling Test Chamber
Temperature cycling test chamber is a kind of laboratory equipment widely used in various industries, its main function is to cycle the product within a certain temperature range to simulate the operation of the product in different temperature environments. The equipment is an important tool to realize product reliability testing, quality control and product performance evaluation.
The temperature cycling test chamber is widely used and can be used for testing in various fields, such as aerospace, automotive, electronics, electric power, medical and other fields. In the aerospace sector, temperature cycle test chambers are used to test the performance of aircraft components at extreme temperatures to ensure their reliability in extreme environments. In the automotive field, the temperature cycle test chamber is used to test the performance of automotive components under different temperature and humidity conditions to ensure that the car can operate normally in a variety of environments. In the field of electronics and power, temperature cycling test chambers are used to test the performance and reliability of electronic equipment under different temperature conditions to ensure that the equipment can operate stably for a long time. In the medical field, temperature cycling test chambers are used to test the performance and reliability of medical equipment under different temperature and humidity conditions to ensure the normal operation of the equipment.
The working principle of the temperature cycling test chamber is to carry out the cycling test by controlling the temperature and humidity in the chamber. The device has a variety of temperature control modes, such as constant temperature control, programmed temperature control, programmed temperature control, etc., which can be selected according to needs. During the test process, the temperature cycling test chamber will place the product in different temperature environments for testing to simulate the use of the product in different environments. After the test is completed, users can improve and upgrade the product according to the test results to improve the reliability and performance of the product.
In short, the temperature cycling test chamber is a laboratory equipment widely used in various industries, and its main function is to cycle the product within a certain temperature range to simulate the operation of the product in different temperature environments. The equipment can be used for testing in various fields, such as aerospace, automotive, electronics, power, medical and other fields, and is an important tool to achieve product reliability testing, quality control and product performance evaluation.
ESS Rapid Temperature Change Stress Screening Machine
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.
Product features of rapid temperature change stress screening machine:
1, It can set different stress screening temperature variation of 5°C/min, 10°C/min and 15°C/min.
2, It can perform rapid temperature change (stress screening), condensation test, high temperature and humidity, temperature and humidity cycle and other tests.
3, It meets the requirements of electronic equipment product stress screening test.
4, It can be switched between equal temperature and average temperature two test methods.
Specification requirements of rapid temperature change stress screening machine:
1, It can set a variety of stress screening (fast temperature variability) 5°C/min, 10°C/min and 15°C/min test conditions.
2, It meets the stress screening of electronic equipment products, lead free process, MIL-STD-2164, MIL-344A-4-16, MIL-2164A-19, NABMAT-9492, GJB-1032-90, GJB/Z34-5.1.6, IPC-9701 and other test requirement.
3, It can perform equal temperature and average temperature test mode.
4, It uses aluminum sheet to verify the load capacity of the machine (non-plastic load).
Vacuum High Temperature Test Chamber
Features of vacuum high temperature test chamber: special high temperature equipment for defoaming and anti-oxidation. And it meets the standards: GB/T2423.1 (IEC60068-2-1), GB/T2423.2 (IEC60068-2-2), ISO16750; JESD22, GB/T 14710, GB/T 13543.
First, product overview of vacuum high temperature test chamber:
New and simple design;
The program of automatic control of pressure and temperature control is easy to operate and advanced in function;
Observation window for easy observation of test material status (optional);
Dual structure in the chamber: the inside of the vacuum container has a dual structure of an inner slot, and a heater is set outside the inner chamber to reduce heat loss, improve temperature uniformity, greatly shorten the temperature rising time, and improve the operating rate of the equipment;
Widely used: can be used for defoaming, degassing, hardening, drying and so on;
Resin liquid mixing and silicone liquid when the defoaming treatment in LED production process, various resin molding degas treatment, IC injection of epoxy resin hardening treatment, drying for electronic parts after water cleaning, vacuum high temperature test chamber can be used in all these process;
Second, different models of vacuum high temperature test chamber:
Model number
Temperature range
Internal volume
Type
Internal size
(W*H*Dmm)
External size
(W*H*Dmm)
VAC-101P
+40～+200℃
91L
Atmospheric pressure range：933～1[*102Pa](abs)
450×450×450
902×1,392×780
VAC-201P
+40～+200℃
216L
Atmospheric pressure range：933～1[*102Pa](abs)
600×600×600
1,052×1,532×930
VAC-301P
+40～+200℃
512L
Atmospheric pressure range：933～1[*102Pa](abs)
800×800×800
1,252×1,772×1,130
Model number
Temperature/pressure range
Internal size
(W*H*Dmm)
LCV-234
(RT+20)°C~+200°C / 0-101kPa(Gauge)
450×450×450
LCV-244
550×550×550
New Energy Environment Test Solution
The problem of new energy reliability is still difficult, and the integrated detection system of electrical stress and environmental stress will provide the best means for research and development and manufacturing.
Industry
Test object
Use
Technology
Solution
New Energy
Battery (secondary battery)
Inspect
Charge and discharge test
High and low temperature (&humidity) test chamber
Rapid temperature (&humidity)change test chamber
Evaluate
Characteristic test
Rapid temperature (&humidity)change test chamber
Fuel cell
/
Temperature resistance
Small ultra-low temperature test chamber
High and low temperature (&humidity) test chamber
Rapid temperature (&humidity)change test chamber
Information Communication Environment Test Solution
The statistical analysis shows that the failure of electronic components accounts for 50% of the failure of electronic complete machine, and the reliability detection technology still faces many challenges.
Industry
Test object
Use
Technology
Solution
IT Communication
Transmission switching equipment
Inspect
High temperature placement test
High and low temperature (&humidity) test chamber
Aging test
High and low temperature (&humidity) test chamber
Evaluate
Thermal cycling test
High and low temperature (&humidity) test chamber
Tellcordia test
High and low temperature (&humidity) test chamber
Thermal cycling test
Rapid temperature (&humidity)change test chamber
Mobile communication terminal
Inspect
Finished operation test
High and low temperature (&humidity) test chamber
Finished operation test
Rapid temperature (&humidity)change test chamber
Evaluate
Temperature and humidity test
High and low temperature (&humidity) test chamber
Computer
Inspect
Finished product screening
Rapid temperature (&humidity)change test chamber
High temperature placement test
High and low temperature (&humidity) test chamber
Aging test
High and low temperature (&humidity) test chamber
External computer storage device
Inspect
Component screening
High and low temperature (&humidity) test chamber
Component screening
Rapid temperature (&humidity)change test chamber
Evaluate
Ensure operation test within temperature and humidity range
High and low temperature (&humidity) test chamber
Ensure operation test within temperature and humidity range
Rapid temperature (&humidity)change test chamber
Thermal Cycling Test(TC) & Thermal Shock Test(TS)
Thermal Cycling Test(TC):
In the life cycle of the product, it may face various environmental conditions, which makes the product appear in the vulnerable part, resulting in product damage or failure, and then affect the reliability of the product.
A series of high and low temperature cycling tests are done on the temperature change at the temperature variation rate of 5~15 degrees per minute, which is not a real simulation of the actual situation. Its purpose is to apply stress to the test piece, accelerate the aging factor of the test piece, so that the test piece may cause damage to the system equipment and components under environmental factors, in order to determine whether the test piece is correctly designed or manufactured.
Common ones are:
Electrical function of the product
The lubricant deteriorates and loses lubrication
Loss of mechanical strength, resulting in cracks and cracks
The deterioration of the material causes chemical action
Scope of application:
Module/system product environment simulation test
Module/System Product Strife test
PCB/PCBA/ Solder Joint Accelerated Stress Test (ALT/AST)...
Thermal Shock Test(TS):
In the life cycle of the product, it may face various environmental conditions, which makes the product appear in the vulnerable part, resulting in product damage or failure, and then affect the reliability of the product.
High and low temperature shock tests under extremely harsh conditions on rapid temperature changes at a temperature variability of 40 degrees per minute are not truly simulated. Its purpose is to apply severe stress to the test piece to accelerate the aging factor of the test piece, so that the test piece may cause potential damage to the system equipment and components under environmental factors, in order to determine whether the test piece is correctly designed or manufactured.
Common ones are:
Electrical function of the product
The product structure is damaged or the strength is reduced
Tin cracking of components
The deterioration of the material causes chemical action
Seal damage
Machine specifications:
Temperature range: -60 ° C to +150 ° C
Recovery time: < 5 minutes
Inside dimension: 370*350*330mm (D×W×H)
Scope of application:
PCB reliability acceleration test
Accelerated life test of vehicle electric module
LED parts accelerated test...
Effects of temperature changes on products:
The coating layer of components falls off, the potting materials and sealing compounds crack, even the sealing shell cracks, and the filling materials leak, which causes the electrical performance of components to decline.
Products composed of different materials, when the temperature changes, the product is not evenly heated, resulting in product deformation, sealing products cracking, glass or glassware and optics broken;
The large temperature difference makes the surface of the product condense or frost at low temperature, evaporates or melts at high temperature, and the result of such repeated action leads to and accelerates the corrosion of the product.
Environmental effects of temperature change:
Broken glass and optical equipment.
The movable part is stuck or loose.
Structure creates separation.
Electrical changes.
Electrical or mechanical failure due to rapid condensation or freezing.
Fracture in a granular or striated manner.
Different shrinkage or expansion characteristics of different materials.
The component is deformed or broken.
Cracks in surface coatings.
Air leak in the containment compartment.
Lab Companion-Rapid Temperature Cycling Test Chamber
Introduction of Lab Companion
With over 20 years of experience, Lab Companion is a world class manufacturer of environmental chambers and an accomplished supplier of turn-key test systems and equipment. All our chambers build on Lab Companion’s reputation for long life and exceptional reliability.
With a scope of design, manufacture and service, Lab Companion has established a quality management system that complies with the International Quality System Standard ISO 9001:2008. Lab Companion’s equipment calibration program is accredited to the International Standard ISO 17025 and the American National Standard ANSI/NCSL-Z-540-1 by A2LA. A2LA is a full member and signatory of the International Laboratory Accreditation Cooperation (ILAC), the Asia Pacific Laboratory Accreditation (APLAC) and the European Cooperation for Accreditation (EA).
Lab Companion’s SE-Series Environmental Test Chambers offer a significantly enhanced airflow system, which provides better gradients and improved product temperature change rates. These chambers utilize Thermotron’s flagship 8800 Programmer/Controller featuring a high resolution 12.1” flat panel display with touch screen user interface, expanded capabilities to graph, data log, edit, access on-screen help, and long term hard drive data storage.
Not only do we offer the highest quality products, we also provide ongoing support designed to keep you up and running long after the initial sale. We provide factory direct local service with an extensive inventory of the parts you might need.
Performance
Temperature range: -70°C to +180°C
Performance: With 23 Kg aluminum load (IEC60068-3-5), the rising rate from +85°C to -40°C is 15℃/min; the cooling rate from -40°C to +85°C is15℃/min too.
Temperature control：± 1°C Dry bulb temperatures from control point after stabilization at the control sensor
Performance is based on an ambient condition of 75°F (23.9°C) and 50% RH
Cooling/Heating Performance based on measurement at the control sensor in the supply air stream
Constructure
Interior
Nonmagnetic Series 300 stainless steel with a high nickel content
Internal seams heliarc welded for hermetic sealing of the liner
Corners and seams designed to allow for expansion and contraction under the temperature extremes encountered
Condensate drain located in the liner floor and under the conditioning plenum
Chamber base is fully welded
“Ultra-Lite” non-settling fiberglass insulation
One adjustable interior stainless steel shelf is standard
Exterior
Die-formed treated sheet steel
Metal access covers provided for easy opening doors to electrical components
Finish water-based, air dry lacquer, sprayed over a cleaned and primed surface
Easy lift-off hinged access doors for servicing the refrigeration system
One 12.5 cm diameter access port with interior weld and removable insulating plug mounted in right hand side wall accessories on hinged door for easy access
Features
Chamber Operation clearly displays helpful run-time information
Graphing Screen offers expanded capabilities, enhanced programming and reporting
System Status displays crucial refrigeration system parameters
Program Entry makes it easy to load, view and edit profiles
Set Up quick-step wizards make profile entry easy
Pop-up Refrigeration Charts for handy reference
Therm-Alarm® provides over & under temperature alarm protection
Activity Log Screen provides comprehensive equipment history
Web Server allows internet access to equipment via Ethernet
User-Friendly Pop-up Key Pad makes data entry quick and easy
Includes:
- Four USB Ports-two External & two Internal
- Ethernet
- RS-232
Technical specifications
1-4 independently programmable channels
Measuring Accuracy: 0.25% of span typical
Selectable °C or °F temperature scale
12.1” (30 cm) color flat panel touch screen display
Resolution: 0.1°C, 0.1%RH, 0.01 for other linear applications
Real time clock included
Sample Rate: Process variable sampled every 0.1 seconds
Proportional Band: Programmable 1.0° to 300°
Control Method: Digital
Intervals: Unlimited
Interval Resolution: 1 sec to 99 hrs,59 min with 1 second resolution
- RS-232
- 10+ Years Data Storage
- Product Temperature Control
- Event Relay Board
Operating Modes: Automatic or Manual
Program Storage: Unlimited
Program Loops:
- Up to 64 loops per program
Loops can be repeated up to 9,999 times program
- Up to 64 nested loops are allowed per
Drug Stability Test
The effectiveness and safety of drugs have attracted much attention, and it is also a livelihood issue that the country and the government attach great importance to. The stability of drugs will affect the efficacy and safety. In order to ensure the quality of drugs and storage containers, stability tests should be performed to determine their effective time and storage state. Stability test mainly studies whether the quality of drugs is affected by environmental factors such as temperature, humidity and light, and whether it changes with time and the correlation between them, and studies the degradation curve of drugs, according to which the effective period is presumed to ensure the effectiveness and safety of drugs when used. This article collects the standard information and test methods required for various stability tests for customers' reference.
First, drug stability test criteria
Storage conditions of drugs:
Storage conditions (Note 2)
Long-term experiment
25℃±2℃ / 60%±5%RH or
30℃±2℃ /65%±5% RH
Accelerated test
40℃±2℃ / 75%±5%RH
Middle test (Note 1)
30℃±2℃ / 65%±5%RH
Note 1: If the long-term test condition has been set at 30℃±2℃/65% ±5%RH, there is no middle test; if the long-term storage condition is 25℃±2℃/ 60% ±5%RH, and there is a significant change in the accelerated test, then middle test should be added. And should be assessed against the criteria of "significant change".
Note 2: Sealed impervious containers such as glass ampoules can be exempted from humidity conditions. Unless otherwise determined, all tests shall be carried out in accordance with the stability test plan in the interim test.
The accelerated test data should be available for six months. The minimum duration of the stability test is 12 months for the middle test and the long-term test.
Store in refrigerator:
Storage conditions
Long-term experiment
5℃±3℃
Accelerated test
25℃±2℃ / 60%±5%RH
Stored in freezer:
Storage conditions
Long-term experiment
-20℃±5℃
Accelerated test
5℃±3℃
If the product containing water or solvents that may be subject to solvent loss is packaged in a semi-permeable container, the stability assessment should be conducted under low relative humidity for a long period of time, or an middle test of 12 months, and an accelerated test of 6 months, in order to prove that the drug placed in the semi-permeable container can withstand the low relative humidity environment.
Containing water or solvents
Storage conditions
Long-term experiment
25℃±2℃ / 40%±5%RH or 30℃±2℃ /35%±5% RH
Accelerated test
40℃±2℃;≤25%RH
Middle test (Note 1)
30℃±2℃ / 35%RH±5%RH
Note 1: If the long-term test condition is 30℃±2℃ / 35%±5%RH, there is no middle test.
The calculation of the relative water loss rate at a constant temperature of 40℃ is as follows:
Substituted relative humidity (A)
Control relative humidity (R)
Water loss rate ratio ([1-R]/[1-A])
60%RH
25%RH
1.9
60%RH
40%RH
1.5
65%RH
35%RH
1.9
75%RH
25%RH
3.0
Illustration: For aqueous drugs placed in semi-permeable containers, the water loss rate at 25%RH is three times that of 75%RH.
Second, Drug stability solutions
Common drug stability test criteria
(Source: Food and Drug Administration, Ministry of Health and Welfare)
Item
Storage conditions
Long-term experiment
25°C /60% RH
Accelerated test
40°C /75%RH
Middle test
30°C/65%RH
(1) Wide temperature range test
Item
Storage conditions
Long-term experiment
Low or sub-zero temperature conditions
Accelerated test
Room temperature and humidity or low temperature conditions
(2) Test equipment
1. Constant temperature and humidity test chamber
2. Drug stability test chamber
Heat Pipe Reliability Test
Heat pipe technology is a heat transfer element called "heat pipe" invented by G.M. rover of Los Alamos National Laboratory in 1963, which makes full use of the principle of heat conduction and the rapid heat transfer properties of the refrigeration medium, and transfers the heat of the heating object quickly to the heat source through the heat pipe. Its thermal conductivity exceeds that of any known metal. Heat pipe technology has been widely used in aerospace, military and other industries, since it has been introduced into the radiator manufacturing industry, making people change the design idea of the traditional radiator, and get rid of the single heat dissipation mode that simply relies on high air volume motor to obtain better heat dissipation effect. The use of heat pipe technology makes the radiator even if the use of low speed, low air volume motor, can also get satisfactory results, so that the noise problem plagued by air cooling heat has been well solved, opening up a new world in the heat dissipation industry.
Heat pipe reliability test conditions:
High temperature stress screening test: 150℃/24 hours
Temperature cycling test:
120℃(10min)←→-30℃(10min), Ramp: 0.5℃, 10cycles 125℃(60min)←→-40℃(60min), Ramp: 2.75℃, 10cycles
Thermal shock test:
120℃(2min)←→-30℃(2min), 250 cycles
125℃(5min)←→-40℃(5min), 250 cycles
100℃(5min)←→-50℃(5min), 2000 cycles(check once after 200 cycles)
High temperature and high humidity test:
85℃/85%R.H./1000 hours
Accelerated aging test:
110℃/85%RH/264h
Other heat pipe test items:
Salt spray test, strength (blasting) test, leakage rate test, vibration test, random vibration test, mechanical shock test, helium combustion test, performance test, wind tunnel test
Natural Convection Test (No Wind Circulation Temperature Test) and Specification
Home entertainment audio-visual equipment and automotive electronics are one of the key products of many manufacturers, and the product in the development process must simulate the adaptability of the product to temperature and electronic characteristics at different temperatures. However, when the general oven or constant temperature and humidity test chamber is used to simulate the temperature environment, both the oven and constant temperature and humidity test chamber have a test area equipped with a circulating fan, so there will be wind speed problems in the test area. During the test, the temperature uniformity is balanced by rotating the circulating fan. Although the temperature uniformity of the test area can be achieved through the wind circulation, the heat of the product to be tested will also be taken away by the circulating air, which will be significantly inconsistent with the actual product in the wind-free use environment (such as the living room, indoor). Because of the relationship of wind circulation, the temperature difference of the product to be tested will be nearly 10 ° C, in order to simulate the actual use of environmental conditions, many people will misunderstand that only the test machine can produce temperature (such as: oven, constant temperature and humidity test chamber) can carry out natural convection test, in fact, this is not the case. In the specification, there are special requirements for wind speed, and a test environment without wind speed is required. Through the natural convection test equipment (no forced wind circulation test), the temperature environment without fan is generated (natural convection test), and then the test integration test is carried out to detect the temperature of the product under test. This solution can be applied to the actual ambient temperature test of household related electronic products or confined Spaces (such as: Large LCD TV, car cockpit, car electronics, laptop, desktop computer, game console, stereo... Etc.).
The difference of the test environment with or without wind circulation for the test of the product to be tested:
If the product to be tested is not energized, the product to be tested will not heat itself, its heat source only absorbs the air heat in the test furnace, and if the product to be tested is energized and heated, the wind circulation in the test furnace will take away the heat of the product to be tested. Every 1 meter increase in wind speed, its heat will be reduced by about 10%. Suppose to simulate the temperature characteristics of electronic products in an indoor environment without air conditioning, if an oven or a constant temperature and humidity test chamber is used to simulate 35 ° C, although the environment in the test area can be controlled within 35 ° C through electric heating and freezing, the wind circulation of the oven and the constant temperature and humidity test chamber will take away the heat of the product to be tested, making the actual temperature of the product to be tested lower than the temperature in the real state of no wind. Therefore, it is necessary to use a natural convection testing machine without wind speed to effectively simulate the actual windless environment (such as: indoor, non-starting car cockpit, instrument chassis, outdoor waterproof box... Such environment).
Indoor environment without wind circulation and solar radiant heat irradiation:
Through the natural convection tester, simulate the client's actual use of the real air conditioning convection environment, hot spot analysis and heat dissipation characteristics of the product evaluation, such as the LCD TV in the photo not only to consider its own heat dissipation, but also to evaluate the impact of thermal radiation outside the window, thermal radiation for the product may produce additional radiant heat above 35 ° C.
Comparison table of wind speed and IC product to be tested:
When the ambient wind speed is faster, the IC surface temperature will also take away the IC surface heat due to the wind cycle, resulting in faster wind speed and lower temperature, when the wind speed is 0, the temperature is 100℃, but when the wind speed reaches 5m/s, the IC surface temperature has been below 80℃.
Unforced air circulation test:
According to the specification requirements of IEC60068-2-2, in the high temperature test process, it is necessary to carry out the test conditions without forced air circulation, the test process needs to be maintained under the wind-free circulation component, and the high temperature test is carried out in the test furnace, so the test cannot be carried out through the constant temperature and humidity test chamber or oven, and the natural convection tester can be used to simulate the free air conditions.
Description of test conditions:
Test specification for unforced air circulation: IEC-68-2-2, GB2423.2, GB2423.2-89 3.3.1
Unforced air circulation test: The test condition of unforced air circulation can simulate the free air condition well
GB2423.2-89 3.1.1:
When measuring under free air conditions, when the temperature of the test sample is stable, the temperature of the most hot spot on the surface is more than 5℃ higher than the temperature of the surrounding large device, it is a heat dissipation test sample, otherwise it is a non-heat dissipation test sample.
GB2423.2-8 10(Test heat dissipation test sample temperature gradient test) :
A standard test procedure is provided to determine the adaptability of thermal electronic products (including components, equipment level other products) to use at high temperatures.
Test requirements:
a. Testing machine without forced air circulation (equipped with a fan or blower)
b. Single test sample
c. The heating rate is not greater than 1℃/min
d. After the temperature of the test sample reaches stability, the test sample is energized or the home electrical load is carried out to detect the electrical performance
Natural convection test chamber features:
1. Can evaluate the heat output of the product to be tested after power, to provide the best distribution uniformity;
2. Combined with digital data collector, effectively measure the relevant temperature information of the product to be tested for synchronous multi-track analysis;
3. Record the information of more than 20 rails (synchronous record the temperature distribution inside the test furnace, multi-track temperature of the product to be tested, average temperature... Etc.).
4. The controller can directly display the multi-track temperature record value and record curve; Multi-track test curves can be stored on a USB drive via the controller;
5. The curve analysis software can intuitively display the multi-track temperature curve and output EXCEL reports, and the controller has three kinds of display [Complex English];
6. Multi-type thermocouple temperature sensor selection (B, E, J, K, N, R, S, T);
7. Scalable to increase heating rate & control stability planning.
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