IEC 60068-2
Instructions:
IEC(International Electrotechnical Association) is the world's oldest non-governmental international electrical standardization organization, for the people's livelihood of the electronic products to develop relevant test specifications and methods, such as: mainframe board, notebook computers, tablets, smartphones, LCD screens, game consoles... The main spirit of its test is extended from IEC, the main representative of which is IEC60068-2, environmental test conditions its [environmental test] refers to the sample exposed to natural and artificial environments, but the performance of its actual use, transportation and storage conditions are evaluated. The environmental test of the sample can be uniform and linear through the use of standardized standards. Environmental testing can simulate whether the product can adapt to environmental changes (temperature, humidity, vibration, temperature change, temperature shock, salt spray, dust) at different stages (storage, transport, use). And verify that the characteristics and quality of the product itself will not be affected by it, low temperature, high temperature, temperature impact can produce mechanical stress, this stress makes the test sample more sensitive to the subsequent test, impact, vibration can produce mechanical stress, this stress can make the sample immediately damaged, air pressure, alternating humid heat, constant humid heat, corrosion application of these tests and can be continued thermal and mechanical stress test effects.
Important IEC specification sharing:
IEC69968-2-1- Cold
Test purpose: To test the ability of automotive components, equipment or other component products to operate and store at low temperatures.
Test methods are divided into:
1.Aa: Temperature sudden change method for non-thermal specimens
2.Ab: Temperature gradient method for non-thermal specimens
3.Ad: Temperature gradient method of thermogenic specimen
Note:
Aa:
1. Static test (without power supply).
2. First cool down to the specified temperature of the specification before placing the test part.
3. After stability, the temperature difference of each point on the specimen does not exceed ±3℃.
4. After the test is completed, the specimen is placed under standard atmospheric pressure until the fog is completely removed: no voltage is added to the specimen during the transfer process.
5. Measure after returning to the original condition (at least 1hr).
Ab:
1. Static test (without power supply).
2. The specimen is placed in the cabinet at room temperature, and the temperature change of the cabinet temperature does not exceed 1℃ per minute.
3. The specimen shall be kept in the cabinet after the test, and the temperature change of the cabinet temperature shall not exceed 1℃ per minute to return to the standard atmospheric pressure; The specimen should not be charged during temperature change.
4. Measure after returning to the original condition (at least 1hr). (The difference between the temperature and the air temperature is more than 5℃).
Ac:
1. Dynamic test (plus power supply) when the temperature of the specimen is stable after charging, the temperature of the specimen surface is the most hot spot.
2. The specimen is placed in the cabinet at room temperature, and the temperature change of the cabinet temperature does not exceed 1℃ per minute.
3. The specimen should be kept in the cabinet after the test, and the temperature change of the cabinet temperature should not exceed 1℃ per minute, and return to the standard atmospheric pressure; The specimen should not be charged during temperature change.
4. Measure after returning to the original condition (at least 1hr).
Test conditions:
1. Temperature :-65,-55,-40,-25,-10,-5,+5°C
2. Resident time :2/16/72/96 hours.
3. Temperature variation rate: no more than 1℃ per minute.
4. Tolerance error :+3°C.
Test setup:
1. Heat generating specimens should be placed in the center of the test cabinet and the wall of the cabinet > 15cm
Sample to specimen > 15cm test cabinet to test volume ratio > 5:1.
2. For heat-generating specimens, if air convection is used, the flow rate should be kept to a minimum.
3. The specimen should be unpacked, and the fixture should have the characteristics of high heat conduction.
IEC 60068-2-2- Dry heat
Test purpose: To test the ability of components, equipment or other component products to operate and store in high temperature environments.
The test method is:
1. Ba: Temperature sudden change method for non-thermal specimens
2.Bb: Temperature gradient method for non-thermal specimens
3.Bc: Temperature sudden change method for thermogenic specimens
4.Bd: Temperature gradient method for thermogenic specimens
Note:
Ba:
1. Static test (without power supply).
2. First cool down to the specified temperature of the specification before placing the test part.
3. After stability, the temperature difference of each point on the specimen does not exceed +5℃.
4. After the test is completed, place the specimen under standard atmospheric pressure and return to the original condition (at least 1hr).
Bb:
1. Static test (without power supply).
2. The specimen is placed in the cabinet at room temperature, and the temperature change of the cabinet temperature does not exceed 1℃ per minute, and the temperature is reduced to the temperature value specified in the specification.
3. The specimen shall be kept in the cabinet after the test, and the temperature change of the cabinet temperature shall not exceed 1℃ per minute to return to the standard atmospheric pressure; The specimen should not be charged during temperature change.
4. Measure after returning to the original condition (at least 1hr).
Bc:
1. Dynamic test (external power supply) When the temperature of the specimen is stable after charging, the difference between the temperature of the hottest spot on the surface of the specimen and the air temperature is more than 5℃.
2. Heat up to the specified temperature of the specification before placing the test part.
3. After stability, the temperature difference of each point on the specimen does not exceed +5℃.
4. After the test is completed, the specimen will be placed under the standard atmospheric pressure, and the measurement will be carried out after the original condition is returned (at least 1hr).
5. The average temperature of the decimal point on the plane of 0~50mm on the bottom surface of the specimen.
Bd:
1. Dynamic test (external power supply) when the temperature of the specimen is stable after charging, the temperature of the most hot spot on the surface of the specimen is more than 5°C different from the air temperature.
2. The specimen is placed in the cabinet at room temperature, and the temperature change of the cabinet temperature does not exceed 1℃ per minute, and rises to the specified temperature value.
3. Return to standard atmospheric pressure; The specimen should not be charged during temperature change.
4. Measure after returning to the original condition (at least 1hr).
Test conditions:
1. The temperature 1000,800,630,500,400,315,250,200,175,155,125,100,85,70,55,40,30 ℃.
1. Resident time: 2/16/72/96 hours.
2. Temperature variation rate: no more than 1℃ per minute. (Average in 5 minutes)
3. Tolerance error: tolerance of ±2℃ below 200℃. (200~1000℃ tolerance ±2%)
IEC 60068-2-2- Test method Ca: Steady damp heat
1. Test purpose:
The purpose of this test method is to determine the adaptability of components, equipment or other products to operation and storage at constant temperature and high relative humidity.
Step 2: Scope
This test method can be applied to both heat-dissipating and non-heat-dissipating specimens.
3. No limits
4. Test steps:
4.1 Specimens shall be inspected visually, electrically and mechanically in accordance with relevant specifications before testing.
4.2 The test specimen must be placed in the test cabinet in accordance with the relevant specifications. In order to avoid the formation of water droplets on the test specimen after it is placed in the cabinet, it is best to preheat the temperature of the test specimen to the temperature condition in the test cabinet in advance.
4.3 The specimen shall be insulated in accordance with the specified residence.
4.4 If specified in the relevant specifications, functional tests and measurements shall be performed during or after the test, and the functional tests shall be performed in accordance with the cycle required in the specifications, and the test pieces shall not be moved out of the test cabinet.
4.5 After the test, the specimen must be placed under standard atmospheric conditions for at least one hour and at most two hours to return to its original condition. Depending on the characteristics of the specimen or the different laboratory energy, the specimen can be removed or retained in the test cabinet to wait for recovery, if you want to remove the time to be as short as possible, preferably not more than five minutes, if maintained in the cabinet the humidity must be reduced to 73% to 77% R.H. within 30 minutes, while the temperature must also reach the laboratory temperature within 30 minutes +1℃ range.
5. Test conditions
5.1 Test temperature: The temperature in the test cabinet should be controlled within the range of 40+2°C.
5.2 Relative humidity: The humidity in the test cabinet should be controlled at 93(+2/-3)% R.H. Within the range.
5.3 Resident time: The resident time can be 4 days, 10 days, 21 days or 56 days.
5.4 Test tolerance: temperature tolerance is +2℃, error of packet content measurement, slow change of temperature and temperature difference in the temperature cabinet. However, in order to facilitate the maintenance of humidity within a certain range, the temperature of any two points in the test cabinet should be maintained within the minimum range as far as possible at any time. If the temperature difference exceeds 1 ° C, the humidity changes beyond the permissible range. Therefore, even short-term temperature changes may need to be controlled within 1 ° C.
6. Test setup
6.1 Temperature and humidity sensing devices must be installed in the test cabinet to monitor the temperature and humidity in the cabinet.
6.2 There shall be no condensation water droplets on the test specimen at the top or wall of the test cabinet.
6.3 The condensed water in the test cabinet must be discharged continuously and shall not be used again unless it is purified (re-purifed).
6.4 When the humidity in the test cabinet is achieved by spraying water into the test cabinet, the moisture resistance coefficient shall not be less than 500Ω.
7. Other
7.1 The temperature and humidity conditions in the test cabinet must be uniform and similar to those in the vicinity of the temperature and humidity sensor.
7.2 The temperature and humidity conditions in the test cabinet shall not be changed during the power-on or functional test of the specimen.
7.3 Precautions to be taken when removing moisture from the specimen surface shall be detailed in the relevant specifications.
IEC 68-2-14 Test method N: Temperature variation
1. Test purpose
The purpose of this test method is to determine the effect of the specimen on the environment of temperature change or continuous temperature change.
Step 2: Scope
This test method can be divided into:
Test method Na: Rapid temperature change within a specified time
Test method Nb: Temperature change at specified temperature variability
Test method Nc: Rapid temperature change by double liquid immersion method.
The first two items apply to components, equipment or other products, and the third item applies to glass-metal seals and similar products.
Step 3 Limit
This test method does not validate high or low temperature environmental effects, and if such conditions are to be validated, "IEC68-2-1 test Method A:" cold "or "IEC 60068-2-2 Test Method B: dry heat" should be used.
4. Test procedure
4.1 Test method Na:
Rapid temperature change in a specific time
4.1.1 Specimens shall be inspected visually, electrically and mechanically in accordance with relevant specifications before testing.
4.1.2 The specimen type shall be unpacked, unpowered and ready for use or other conditions specified in relevant specifications. The initial condition of the specimen was room temperature in the laboratory.
4.1.3 Adjust the temperature of the two temperature cabinets respectively to the specified high and low temperature conditions.
4.1.4 Place the specimen in the low-temperature cabinet and keep it warm according to the specified residence time.
4.1.5 Move the specimen into the high-temperature cabinet and keep it warm according to the specified residence time.
4.1.6 The transfer time of high and low temperature shall be subject to the test conditions.
4.1.7 Repeat the procedure of Steps 4.1.4 and 4.1.5 four times
4.1.8 After the test, the specimen should be placed under standard atmospheric conditions and kept for a certain time to make the specimen reach temperature stability. The response time shall refer to the relevant regulations.
4.1.9 After the test, the specimens shall be inspected visually, electrically and mechanically in accordance with relevant specifications.
4.2 Test method Nb:
Temperature change at a specific temperature variability
4.2.1 The specimens shall be inspected visually, electrically and mechanically in accordance with relevant specifications before testing.
4.2.2 Place the test piece in the temperature cabinet. The shape of the test piece should be unpacked, unpowered and ready for use or other conditions specified in relevant specifications. The initial condition of the specimen was room temperature in the laboratory.
The specimen can be made operational if required by the relevant specification.
4.2.3 The temperature of the cabinet shall be lowered to the prescribed low temperature condition, and the insulation shall be carried out according to the prescribed residence time
4.2.4 The temperature of the cabinet shall be raised to the specified high temperature condition, and heat preservation shall be carried out according to the specified residence time
4.2.5 The temperature variability of high and low temperature shall be subject to the test conditions.
4.2.6 Repeat the procedure in Steps 4.2.3 and 4.2.4:
Electrical and mechanical tests shall be performed during the test.
Record the time used for electrical and mechanical testing.
After the test, the specimen should be placed under standard atmospheric conditions and kept for a certain time to make the specimen reach the temperature stability recovery time referred to the relevant specifications.
After the test, the specimens shall be inspected visually, electrically and mechanically in accordance with the relevant specifications
5. Test conditions
Test conditions can be selected by the following appropriate temperature conditions and test time or in accordance with the relevant specifications,
5.1 Test method Na:
Rapid temperature change in a specific time
High temperature: 1000800630500400315250200175155125100,85,70,55,4030 ° C
Low temperature :-65,-55,-40,-25.-10.-5 °C
Humidity: Vapor content per cubic meter of air should be less than 20 grams (equivalent to 50% relative humidity at 35 ° C).
Residence time: The temperature adjustment time of the temperature cabinet can be 3 hours, 2 hours, 1 hour, 30 minutes or 10 minutes, if there is no provision, it is set to 3 hours. After the test piece is placed in the temperature cabinet, the temperature adjustment time cannot exceed one-tenth of the residence time. Transfer time: manual 2~3 minutes, automatic less than 30 seconds, small specimen less than 10 seconds.
Number of cycles :5 cycles.
Test tolerance: The tolerance of temperature below 200℃ is +2℃
The tolerance of the temperature between 250 and 1000C is +2% of the test temperature. If the size of the temperature cabinet cannot meet the above tolerance requirements, the tolerance can be relaxed: the tolerance of the temperature below 100 ° C is ±3 ° C, and the tolerance of the temperature between 100 and 200 ° C is ±5 ° C (the tolerance relaxation should be indicated in the report).
5.2 Test method Nb:
Temperature change at a specific temperature variability
High temperature: 1000800630500400315250200175155125100,85,70 55403 0 'C
Low temperature :-65,-55,-40,-25,-10,-5,5℃
Humidity: Vapor per cubic meter of air should be less than 20 grams (equivalent to 50% relative humidity at 35 ° C) Residence time: including rising and cooling time can be 3 hours, 2 hours, 1 hour, 30 minutes or 10 minutes, if there is no provision, set to 3 hours.
Temperature variability: The average temperature fluctuation of the temperature cabinet within 5 minutes is 1+0.2 ° C /min, 3+0.6 ° C /min, or 5+1 ° C /min.
Number of cycles :2 cycles.
Test tolerance: The tolerance of temperature below 200℃ is +2℃.
The tolerance of the temperature between 250 and 1000℃C is +2% of the test temperature. If the size of the temperature cabinet cannot meet the above tolerance requirements, the tolerance can be relaxed. The tolerance of the temperature below 100 ° C is +3 ° C. The temperature between 100 ° C and 200 ° C is +5 ° C. (The tolerance relaxation should be indicated in the report).
6. Test setup
6.1 Test method Na:
Rapid temperature change in a specific time
The difference between the inner wall temperature of the high and low temperature cabinets and the temperature test specifications shall not exceed 3% and 8%(shown in °K) respectively to avoid thermal radiation problems.
The thermogenic specimen should be placed in the center of the test cabinet as far as possible, and the distance between the specimen and the cabinet wall, the specimen and the specimen should be greater than 10 cm, and the ratio of the volume of the temperature cabinet and the specimen should be greater than 5:1.
6.2 Test method Nb:
Temperature change at a specific temperature variability
Specimens shall be inspected visually, electrically and mechanically in accordance with relevant specifications before testing.
The specimen shall be in unpacked, unpowered and ready for use condition or other conditions specified in relevant specifications. The initial condition of the specimen was room temperature in the laboratory.
Adjust the temperature of the two temperature cabinets respectively to the specified high and low temperature conditions
The specimen is placed in a low-temperature cabinet and kept warm according to the specified residence time
The specimen is placed in a high temperature cabinet and insulated according to the specified residence time.
The transfer time of high and low temperature shall be performed according to the test conditions.
Repeat the procedure of steps d and e four times.
After the test, the specimen should be placed under standard atmospheric conditions and kept for a certain time to make the specimen reach the temperature stability recovery time referred to the relevant specifications.
After the test, the specimens shall be inspected visually, electrically and mechanically in accordance with the relevant specifications
6.3 Test method NC:
Rapid temperature change of double liquid soaking method
The liquid used in the test shall be compatible with the specimen and shall not harm the specimen.
7. Others
7.1 Test method Na:
Rapid temperature change in a specific time
When the specimen is placed in the temperature cabinet, the temperature and air flow rate in the cabinet must reach the specified temperature specification and tolerance within one-tenth of the holding time.
The air in the cabinet must be maintained in a circle, and the air flow rate near the specimen must not be less than 2 meters per second (2m/s).
If the specimen is transferred from the high or low temperature cabinet, the holding time cannot be completed for some reason, it will stay in the previous holding state (preferably at low temperature).
7.2 Test method Nb:
The air in the cabinet must be maintained in a circle at a specific temperature variability, and the air flow rate near the specimen must not be less than 2 meters per second (2m/s).
7.3 Test method NC:
Rapid temperature change of double liquid soaking method
When the specimen is immersed in the liquid, it can be quickly transferred between the two containers, and the liquid cannot be stirred.
What are the High and Low Temperature Explosion-proof Devices?
Due to the particularity of the test product, during the test process, the test product may produce a large amount of gas in the high temperature or high pressure state, which may catch fire and explode. In order to ensure production safety, preventive safety protection devices can be used as optional equipment. Therefore, the high and low temperature test chamber needs to add special devices - explosion-proof devices when testing these special products. Today, let's talk about what are the high and low temperature explosion-proof devices.
1. Pressure relief port
When the air generated in the test chamber increases and the gas pressure in the chamber reaches a threshold, the pressure relief port automatically opens and releases the pressure outwards. This design ensures that when the system overpressure, the pressure can be released, thereby preventing the system from collapsing or exploding. The location and number of pressure relief ports are determined according to the specific fire extinguishing system design and application requirements.
2. Smoke detector
The smoke detector mainly realizes fire prevention by monitoring the concentration of smoke. The ionic smoke sensor is used inside the smoke detector. The ionic smoke sensor is a kind of sensor with advanced technology and stable and reliable operation. When the concentration of smoke particles in the chamber is greater than the threshold, it will sense and alarm to remind the production to stop operation and achieve the effect of preventing fire.
3. Gas detector
A gas detector is an instrument that detects the concentration of a gas. The instrument is suitable for dangerous places where combustible or toxic gases exist, and can continuously detect the content of the measured gas in the air within the lower explosive limit for a long time. The gas diffuses into the working electrode of the sensor through the back of the porous film, where the gas is oxidized or reduced. This electrochemical reaction causes a change in the current flowing through the external circuit, and the gas concentration can be measured by measuring the size of the current.
4. Smoke exhaust system
The air inlet of the pressurized fan is directly connected with the outdoor air. In order to prevent the outdoor air from being polluted by smoke, the air inlet of the supply fan should not be located at the same level as the air outlet of the exhaust machine. A one-way air valve should be installed on the outlet or inlet air pipe of the fan. Mechanical smoke exhaust system adopts smoke exhaust fan for mechanical exhaust air. According to relevant information, a well-designed mechanical smoke exhaust system can discharge 80% of the heat in the fire, so that the temperature of the fire scene is greatly reduced, and it has an important role in the safety of personnel evacuation and fire fighting.
5. Electromagnetic lock and mechanical door buckle
The electromagnetic lock uses the electromagnetic principle to achieve the fixing of the lock body, without the need to use a mechanical lock tongue, so the electromagnetic lock does not exist the possibility of mechanical lock tongue damage or forced destruction. The electromagnetic lock has a high anti-impact strength, when the external impact force acts on the lock body, the lock body will not be easily destroyed, and there will be certain protective measures when the explosion occurs.
6. Automatic fire extinguishing device
The automatic fire extinguishing device is mainly composed of four parts: detector (thermal energy detector, flame detector, smoke detector), fire extinguisher (carbon dioxide extinguisher), digital temperature control alarm and communication module. Through the digital communication module in the device, the real-time temperature changes, alarm status and fire extinguisher information in the fire area can be remotely monitored and controlled, which can not only remotely monitor the various states of the automatic fire extinguishing device, but also master the real-time changes in the fire area, which can minimize the loss of life and property when the fire occurs.
7. Indicator and warning light
Communicate equipment status or transmission status by visual and acoustic signals to machine operators, technicians, production managers and plant personnel.
What are the Safety Protection Systems of the High and Low Temperature Test Chamber?
1, Leakage/surge protection:Leakage circuit breaker leakage protection FUSE.RC electronic surge protection from Taiwan
2, The controller internal self-automatic detection and protection device
(1) Temperature/humidity sensor: The controller controls the temperature and humidity in the test area within the set range through the temperature and humidity sensor
(2) Controller overtemperature alarm: when the heating tube in the chamber continues to heat up and exceeds the temperature set by the internal parameters of the controller, the buzzer in it will alarm and need to be manually reset and reused
3, Fault detection control interface: external fault automatic detection protection Settings
(1) The first layer of high temperature overtemperature protection: operation control overtemperature protection Settings
(2) The second layer of high temperature and overtemperature protection: the use of anti-dry burning overtemperature protector to protect the system will not be heated all the time to burn the equipment
(3) Water break and air burning protection: humidity is protected by anti-dry burning overtemperature protector
(4) Compressor protection: refrigerant pressure protection and over-load protection device
4, Fault abnormal protection: when the fault occurs, cut off the control power supply and the fault cause indication and alarm output signal
5, Automatic water shortage warning: the machine water shortage active warning
6, Dynamic high and low temperature protection: with the setting conditions to dynamically adjust the high and low temperature protection value
Comparison of Natural Convection Test Chamber, Constant Temperature and Humidity Test Chamber and High Temperature Oven
Instructions:
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 using a general oven or thermal and humidity chamber to simulate the temperature environment, either the oven or thermal and humidity chamber has 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℃. In order to simulate the actual use of environmental conditions, many people will misunderstand that only the test chamber can produce temperature (such as: oven, constant temperature humidity 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 and software, the temperature environment without passing through the fan (natural convection) is generated, and the test integration test is performed for the temperature detection of the product under test. This solution can be used for home related electronics or real-world ambient temperature testing in confined Spaces (e.g., large LCD TV, car cockpits, automotive electronics, laptops, desktops, game consoles, stereos, etc.).
Unforced air circulation test specification :IEC-68-2-2, GB2423.2, GB2423.2-89 3.31 The difference between the test environment with or without wind circulation and the test of products to be tested:
Instructions:
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 humidifier is used to simulate 35 °C, although the environment can be controlled within 35 °C through electric heating and compressor, the wind circulation of the oven and the thermal and humidify test chamber will take away the heat of the product to be tested. So that the actual temperature of the product to be tested is lower than the temperature under the real windless state. It is necessary to use a natural convection test chamber without wind speed to effectively simulate the actual windless environment (indoor, no starting car cockpit, instrument chassis, outdoor waterproof chamber... Such environment).
Comparison table of wind speed and IC product to be tested:
Description: 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 the faster the wind speed and the lower the temperature.
Comparison of Climatic Test and Environmental Test
Climate environment test -- constant temperature and humidity test chamber, high and low temperature test chamber, cold and hot shock test chamber, wet and heat alternating test chamber, rapid temperature change test chamber, linear temperature change test chamber, walk-in constant temperature and humidity test chamber, etc. They all involve temperature control.
Because there are multiple temperature control points to choose from, the climate chamber temperature control method also has three solutions: inlet temperature control, product temperature control and "cascade" temperature control. The first two are single-point temperature control, and the third is two-parameter temperature control.
Single point temperature control method has been very mature and widely used.
Most of the early control methods were "ping-pong" switch control, commonly known as heating when it's cold and cooling when it's hot. This control mode is a feedback control mode. When the temperature of the circulating air flow is higher than the set temperature, the electromagnetic valve of refrigeration is opened to deliver cold volume to the circulating air flow and reduce the temperature of the air flow. Otherwise, the circuit switch of the heating device is switched on to directly heat the circulating air flow. Raise the temperature of the air stream. This control mode requires that the refrigeration device and heating components of the test chamber are always in a standby working state, which not only wastes a lot of energy, but also the controlled parameter (temperature) is always in an "oscillation" state, and the control accuracy is not high.
Now the single-point temperature control method is mostly changed to the universal proportional differential integral (PID) control method, which can give the controlled temperature correction according to the past change of the controlled parameter (integral control) and the change trend (differential control), which not only saves energy, but also the "oscillation" amplitude is small and the control accuracy is high.
Dual-parameter temperature control is to collect the temperature value of the air inlet of the test chamber and the temperature value near the product at the same time. The air inlet of the test chamber is very close to the installation position of the evaporator and heater in the air modulation room, and its magnitude directly reflects the air modulation result. Using this temperature value as the feedback control parameter has the advantage of quickly modulating the status parameters of the circulating air.
The temperature value near the product indicates the real temperature environmental conditions suffered by the product, which is the requirement of the environmental test specification. Using this temperature value as the parameter of feedback control can ensure the effectiveness and credibility of the temperature environmental test, so this approach takes into account the advantages of both and the requirements of the actual test. The dual-parameter temperature control strategy can be the independent "time-sharing control" of the two groups of temperature data, or the weighted two temperature values can be combined into one temperature value as a feedback control signal according to a certain weighting coefficient, and the value of the weighting coefficient is related to the size of the test chamber, the wind speed of the circulating air flow, the size of the temperature change rate, the heat output of the product work and other parameters.
Because heat transfer is a complex dynamic physical process, and is greatly affected by the atmospheric environment conditions around the test chamber, the working state of the tested sample itself, and the complexity of the structure, it is difficult to establish a perfect mathematical model for the temperature and humidity control of the test chamber. In order to improve the stability and accuracy of control, fuzzy logic control theory and method are introduced in the control of some temperature test chambers. In the control process, the thinking mode of human is simulated, and the predictive control is adopted to control the temperature and humidity space field more quickly.
Compared with the temperature, the selection of humidity measurement and control points is relatively simple. During the circulation flow of the well-regulated humid air into the high and low temperature cycle test chamber, the exchange of water molecules between the wet air and the test piece and the four walls of the test chamber is very small. As long as the temperature of the circulating air is stable, the circulating air flow from entering the test chamber to exiting the test chamber is in the process. The moisture content of wet air changes very little. Therefore, the relative humidity value of the detected air at any point of the circulating air flow field in the test box, such as the inlet, the middle stream of the flow field or the return air outlet, is basically the same. Because of this, in many test chambers that use the wet and dry bulb method to measure humidity, the wet and dry bulb sensor is installed at the return air outlet of the test chamber. Moreover, from the structural design of the test box and the convenience of maintenance in use, the wet and dry bulb sensor used for relative humidity measurement and control is placed at the return air inlet for easy installation, and also helps to regularly replace the wet bulb gauze and clean the temperature sensing head of the resistance PT100, and according to the requirements of the GJB150.9A wet heat test 6.1.3. The wind speed passing through the wet-bulb sensor should not be lower than 4.6m/s. The wet-bulb sensor with a small fan is installed at the return air outlet for easier maintenance and use.
Application of Thermal Shock Test Chamber
Thermal shock test chamber is an indispensable test equipment for aviation, automotive, home appliances, scientific research and other fields, used to test and determine the parameters and performance of electrical, electronic and other products and materials after temperature environment changes in high temperature, low temperature, alternating humidity and heat degree or constant test; Or constant humid heat test after the temperature environment changes the parameters and performance. Applicable to schools, factories, research positions, etc.
1, the high and low temperature impact test chamber with automatic, high-precision system loop, any part action, fully PLC locking processing, all use PID automatic calculation control, high temperature control precision, advanced scientific air circulation cycle design, make the indoor temperature uniform, avoid any dead corners; The complete protection device avoids any possible hidden dangers and ensures the long-term reliability of the equipment.
2, high and low temperature impact test chamber adopts advanced measuring device, and the controller adopts a large color LCD man-machine touch dialogue LCD man-machine interface controller, which is simple to operate, easy to learn, stable and reliable, and displays the complete system operation status, execution and setting program curve in Chinese and English. With 96 test specifications independently set, impact time 999 hours 59 minutes, cycle cycle 1~999 times can be set, can realize the automatic operation of the refrigerator, to a large extent to achieve automation, reduce the workload of the operator, can automatically start and stop working at any time.
3, The left side of the chamber has a test hole with a diameter of 50mm, which can be used for wiring test parts with external power load. Can be independently set high temperature, low temperature and cold and thermal shock three different conditions of the function, and in the implementation of cold and thermal shock conditions, you can choose two or three trough and cold flushing, hot flushing impact function, with high and low temperature testing machine function.
Solar Module Test Project
1. solar module reliability test specification:
The reliability test of the solar module is to confirm the performance of the solar module (early), and the test specifications for the module are mainly IEC61215, IEC61646, UL1703 three test specifications. IEC61215 is suitable for crystalline (Si) modules; IEC61646 is suitable for thin-film (Thin-flm) modules; The UL1703 is suitable for both crystalline and thin film solar modules. In addition, the GB and CNS solar energy specifications are partially modified from the IEC.
2. the relationship and importance of Macro Exhibition and solar energy test projects:
According to IEC61215, IEC61646 test items a total of about 10 (solar module test items corresponding to the general table). Among them, the test equipment manufactured by Hongjian will be used, and the relevant test conditions are temperature cycling (Thermal cycling, 10.11). There are three categories of Humidity freeze (10.12) and Damp heat (10.13), while UL1703 only has two items of temperature cycle wet freezing without the item of damp heat.
3. Thermal cycling test (Thermal cycling)lEC61215-10-11:
Solar module temperature cycle test is used to determine the fatigue, thermal failure, or other stress failure caused by repeated changes in temperature of the module. The current number of temperature cycles is 200 times, and the future trend will be 600 times (according to the test results of the American Association for Renewable Energy [NREL], the power degradation rate of 600 times is greater than 200 times as much as twice).
Through the temperature cycle: defects of the module can be found: crack growth, module cracks, warping, sealing material delamination, point shedding, glass corrosion... Let's wait.
Temperature conditions: Low temperature :-40℃, high temperature :85°C(IEC), 90 °C(UL), the fastest temperature variability (average):100 °C /h, 120 °C /h, relevant measurements need to be carried out during the test (using the Qingsheng solar energy measurement system), the test process needs to measure the module: module surface temperature, voltage and current, ground continuity, insulation... Let's wait.
4. the purpose of the temperature cycle test process through bias:
Temperature cycle test process, the specification requires through bias, the purpose of the test is to make the defective Cell heat to accelerate aging and accelerate failure test purposes, so it needs to be energized above 25℃ during the temperature cycle process, the laboratory in the United States has statistics, It was found that the difference between the failure rate of the solar module with power and without power is as high as 30%, and the experimental data indicates that if there is no power, the solar module is not easy to fail in the temperature cycle environment, so when carrying out the temperature cycle test of the solar cell (Cel)& module, it needs to be matched with a special measurement system.
5. the introduction of wet freezing test lEC61215-10-12:
Description: To determine whether the component is sufficiently resistant to corrosion damage and the ability of moisture expansion to expand the material molecules, frozen moisture is the stress to determine the cause of failure. For the product to be tested, the test stress is high temperature and high humidity (85℃/85%R.H) to low temperature (-40℃ humidity 85%R.H). Maintain to 25℃), and low temperature rise to high temperature and high humidity, rather than 85℃/85%R.H./20 hours, 85℃/85%R.H./20 hours, the purpose of 85℃/85%R.H./20 hours is to let the module surrounding full of water, 20 hours dwell time is too short, is not enough for water to penetrate into the module and junction box inside.
Through wet freezing test: Module defects can be found: cracks, warping, severe corrosion, lamination of sealing materials, failure of adhesive delamination junction box & water accumulation, wet insulation **... Etc.
Test conditions: 85 ℃ / 85% R.H. (h) 20-40 ℃ (0.5 ~ 4 h), maximum heat up 100, 120 ℃ / h, and maximum temperature of 200 ° C/h.
6. Purpose of wet freezing test:
The wet freezing test method is mainly to perform two kinds of damage to the solar module in a snowy environment.
(1). High temperature and humidity (85℃/85%R.H.) drop to -4℃ before 25℃, humidity should be controlled at 85%+5% RH. The purpose of this is to simulate the high humidity sudden change before the snow.
Before the snow, the environment will show a high humidity state, and when the temperature drops to 0℃, the water gas around the module and the junction box sealant will freeze. When the water gas freezes, its volume will expand to 1.1 times of the original, and the destruction method of ice expansion after the water gas penetrates the material gap through the water gas to achieve the purpose of this test. At present, the statistical results of wet freezing have the highest damage to junction box sealant, which will cause junction box degumming and water, and the failure ratio of module is estimated at 7%.
(2). The purpose of heating up from low temperature (-40℃) and humidity (50℃/85%R.H.) is to simulate the temperature rise in the module at sunrise in a snowy climate. Although the outdoor environment is still below 0℃, the solar module will generate electricity when there is light, and because the snow is still on the module, the heat spot effect will occur in the module. The temperature inside the module will also reach 50 ° C.
7. wet heat test (Damp heat) test IEC61215-10-13:
Description: To determine the ability of the module to resist long-term moisture penetration, according to the test results of BP Solar, its 1000 hours is not enough. The actual condition is found that the time to make the module have problems needs at least 1250 hours. According to the current requirements of the specification, the wet heat test process is not powered on, but the future trend is also to be powered on (positive and reverse bias), because it can accelerate the aging and failure of solar cells.
Test conditions: 85℃/85%R.H., time :1000 hours Defects can be found through the wet and thermal test: CELL delamination EVA(delamination, discoloration, bubble formation, atomization, Browning), connection line blackening, TCO corrosion, spot corrosion, Thin-film yellow discoloration, junction box degumming off
Working Principle of UV Weathering Test Chamber
Uv weathering test chamber is a kind of experimental equipment specially used to test the durability and stability of materials and products under ultraviolet radiation. Its working principle revolves around mimicking UV radiation conditions in the natural environment to assess how materials behave when exposed to sunlight for long periods of time. The chamber is equipped with a series of high-intensity ultraviolet light sources that effectively emit ultraviolet light in a specific wavelength range, mimicking the UV-A and UV-B bands of natural sunlight.
During the test, the sample is placed in the test chamber, and ultraviolet radiation will cause changes in the chemical structure of the surface of the material, such as color fading, strength reduction and brittleness increase. At the same time, the test chamber can also be combined with environmental factors such as temperature and humidity for a more comprehensive evaluation of the sample. For example, the humidity control system in the laboratory can simulate the effects of rain and moisture, while the temperature control equipment can reproduce extreme hot or cold conditions.
By exposing the samples to multiple rounds of ultraviolet radiation at different time periods, researchers were able to collect a large amount of experimental data and analyze the aging resistance and service life of the samples in depth. These data play a vital role in material development, product quality control and market demand analysis. In addition, the use of UV weathering test chambers also helps companies anticipate possible performance problems before the launch of new products, so as to make timely adjustments and improvements.
Such tests are not only applicable to plastics, coatings, fibers and other materials, but also widely used in various industries such as automobiles, construction fields and even electronic products. By studying the performance of products in different climatic conditions, companies can improve the competitiveness of their products in the market, but also contribute to the environmental cause, because good weather resistance products usually mean a longer life cycle and less material waste.
In short, UV weathering test chambers play a key role in materials science and product development, not only allowing developers to better grasp material properties, but also for consumers to bring higher quality and more durable products. In the future development of science and technology, with the continuous progress of ultraviolet weathering test technology, we may be able to witness the birth of more new materials and new products, adding more convenience and beauty to our lives.
Definition and Characteristics of UV Weathering Test Chamber
Uv weathering test chamber is a professional equipment used to simulate and evaluate the resistance of materials to ultraviolet radiation and corresponding climatic conditions. Its core function is to simulate the effect of ultraviolet light on materials in the natural environment through artificially controlled ultraviolet radiation, temperature and humidity changes, so as to conduct comprehensive and systematic tests on the durability, color stability and physical properties of materials. In recent years, with the development of science and technology and the continuous improvement of material performance requirements, the application of UV weathering test chambers has become more and more extensive, covering plastics, coatings, rubber, textiles and other fields.
The characteristics of the equipment are mainly reflected in its high efficiency and accuracy. First of all, the UV weathering test chamber uses a high-intensity ultraviolet lamp, which emits an ultraviolet spectrum close to sunlight, which can accurately simulate the lighting conditions in the real environment. Secondly, it has a real-time monitoring and control system, which can precisely regulate the internal temperature, humidity and UV intensity to ensure the stability of the test process and the reliability of the results. In addition, the internal material and structural design of the test chamber is also particularly important, which usually uses corrosion resistant and oxidation resistant materials to extend the service life of the equipment and improve the accuracy of the test.
In addition, the application of UV weathering test chamber is not only limited to the aging detection of materials, but also can predict and improve the performance of materials, making manufacturers more forward-looking and scientific in material selection and product design. The use of this equipment to a large extent reduces the quality problems caused by the lack of weather resistance of the product and improves the market competitiveness of the product. Therefore, in the material research and development, the UV weathering test chamber can be described as an indispensable auxiliary tool, which helps enterprises quickly detect and optimize material properties to meet the changing needs of the market.
In short, UV weathering test chamber, as an advanced testing technology, is leading the progress and innovation in the field of materials science. With the increasing demand for environmentally friendly materials and long-lasting products, the importance of such equipment will only become more prominent. Its scientific, reliable and efficient will help all walks of life to develop more high-quality products to cope with more unknown challenges in the future.
High and Low Temperature Test Standard of PC Plastic Material
1. High temperature test
After being placed at 80±2℃ for 4 hours and at normal temperature for 2 hours, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance meet the normal requirements, and there are no abnormal phenomena such as deformation, warping, and degumming in appearance. The key convex point collapses at high temperature and the press force becomes smaller without assessment.
2. Low temperature test
After being placed at -30±2℃ for 4 hours and at normal temperature for 2 hours, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance meet normal requirements, and there are no abnormal phenomena such as deformation, warping, and degumming in appearance.
3. Temperature cycle test
Put in 70±2℃ environment for 30 minutes, take out at room temperature for 5 minutes; Leave in -20±2℃ environment for 30 minutes, remove and leave at room temperature for 5 minutes. After such 5 cycles, the dimensions, insulation resistance, voltage resistance, key function, circuit resistance meet the normal requirements, and the appearance of no deformation, warping, degumming and other abnormal phenomena. The key convex point collapses at high temperature and the press force becomes smaller without assessment.
4. Heat resistance
After being placed in an environment with a temperature of 40±2℃ and a relative humidity of 93±2%rh for 48 hours, the dimensions, insulation resistance, voltage resistance, key function, and loop resistance meet normal requirements, and the appearance is not deformed, warped, or degumped. The key convex point collapses at high temperature and the press force becomes smaller without assessment.
National standard value for plastic testing:
Gb1033-86 Plastic density and relative density test method
Gbl636-79 Test method for apparent density of moulding plastics
GB/ T7155.1-87 Thermoplastic pipe and pipe fittings density determination part: polyethylene pipe and pipe fittings reference density determination
GB/ T7155.2-87 Thermoplastic pipes and fittings -- Determination of density -- Part L: Determination of density of polypropylene pipes and fittings
GB/T1039-92 General rules for testing mechanical properties of plastics
GB/ T14234-93 Surface roughness of plastic parts
Gb8807-88 plastic mirror gloss test method
Test method for tensile properties of GBL3022-9L plastic film
GB/ TL040-92 Test method for tensile properties of plastics
Test method for tensile properties of GB/ T8804.1-88 thermoplastic pipes polyvinyl chloride pipes
GB/ T8804.2-88 Test methods for tensile properties of thermoplastic pipes Polyethylene pipes
Hg2-163-65 plastic low temperature elongation test method
GB/ T5471-85 Method for preparing thermosetting molding specimens
HG/ T2-1122-77 thermoplastic sample preparation method
GB/ T9352-88 thermoplastic compression sample preparation
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LED Street Lamp Test Specification
LED street lights are currently one of the key implementation methods to save energy and reduce carbon, all countries in the world have been in full swing to replace the original traditional street lights with LED street lights, and the new street is directly limited to the use of LED street lights to save energy. At present, the world LED street lamp market size of about 80 million, LED lamp light source whether it is heat, service life, output spectrum, output illuminance, material characteristics, are different from traditional mercury lamp or high-pressure sodium lamp. The test conditions and test methods of LED street lights are different from traditional lamps. Lab Companion collected the reliability test methods related to LED street lights at present and provide you with reference to help you understanding the related tests about LED.
LED street lamp test specification abbreviation:
LED street lamp test standard specification, LED street lamp test method technical specification, LED street lamp standard and test method, night landscape engineering semiconductor lighting device components product technical specification, semiconductor lighting night landscape engineering construction quality acceptance technical specification, IEC 61347LED power supply safety regulation
LED street lamp test specification conditions:
CJJ45-2006 Urban road lighting design standard, UL1598 lamps safety standard, UL48 wire and cable safety standard, UL8750 light-emitting diode safety standard, CNS13089 light-emitting diode large lamp durability Test - pre-burning test - outdoor, Waterproof Test: IP65, American Standard for LED lamps, EN 60598-1, EN 60598-2 Street lamp test
LED large lamp quality certification test project:
Temperature cycle, temperature and humidity cycle, high temperature preservation, moisture resistance, vibration, shock, continuous power, salt water spray, acceleration, solder heat resistance, solder adhesion, terminal strength, natural drop, dust test
LED large lamp quality certification test conditions:
Temperature cycle: 125℃(30min)←R.T.(5min)→-65℃(30min)/5cycle
LED street lamp (light-emitting diode outdoor display with large lights) failure determination:
a. The axis light is lower than the residual rating of 50%
b. Forward voltage is greater than 20% of the rated value
c. Reverse current greater than 100% of the rated value
d. The half height wave length and half power Angle of the light exceed the limited maximum value or the limited minimum value meet the above conditions, and determine the failure of the LED street lamp
Note: The luminous efficiency of LED street lamp is recommended to be at least 45lm/W or above (the luminous efficiency of LED light source must be about 70 ~ 80lm/W)
High temperature storage: maximum storage temperature 1000 hours [special level 3000 hours]
Moisture resistance: 60℃/90%R.H./1000 hours [characteristic level 2000 hours]/ applying bias
Brine spray: 35℃/ concentration 5%/18 hours [24 hours special level]
Continuous power: maximum forward current 1000 hours
Natural fall: Fall height 75cm/ fall times 3 times/fall material smooth maple wood
Dust test: continuous 360 hours of 50℃ ring temperature test
Vibration: 100 ~ 2000Hz, 196m/s^2, 48 hours
Impact: Grade F[Acceleration 14700m/s^2, pulse amplitude 0.5ms, six directions, three times in each direction]
Equal acceleration: Acceleration is applied in all directions (class D: 196000 m/s^2) for 1 minute
Solder heat resistance: 260℃/10 seconds /1 time
Solder adhesion: 250℃/5 seconds
Terminal strength
LED large lamp batch quality test project:
Terminal strength, solder heat resistance, temperature cycle, moisture resistance, continuous power, high temperature storage
LED large lamp batch quality test conditions:
Moisture resistance: 60℃/90%R.H./168 hours (no failure)/500 hours (one failure allowed)[test number 10 / apply bias]
Continuous power on: maximum forward current /168 hours (no failure)/500 hours (one failure allowed)[test number 10]
High temperature storage: maximum storage temperature /168 hours (no failure)500 hours (one failure allowed)[test number 10]
Solder heat resistance: 260℃/10 seconds /1 time
Solder adhesion: 250℃/5 seconds
LED large lamp regular quality test project:
Vibration, shock, acceleration, moisture resistance, continuous power, high temperature preservation
Regular quality test conditions for LED large lights:
Moisture resistance: 60℃/90%R.H./1000 hours
Continuous power: maximum forward current /1000 hours
High temperature storage: Maximum storage temperature /1000 hours
Vibration: 100 ~ 2000Hz, 196m/s^2, 48 hours
Impact: Grade F[Acceleration 14700m/s^2, pulse amplitude 0.5ms, six directions, three times in each direction]
Equal acceleration: Acceleration is applied in all directions (class D: 196000 m/s^2) for 1 minute
LED large lamp screening test project:
Acceleration test, temperature cycle, high temperature preservation, pre-burning test
LED large light screening test conditions:
Constant acceleration test: Apply acceleration (grade D: 196000 m/s^2) in each direction for 1 minute
Temperature cycle: 85℃(30min)←R.T.(5min)→-40℃(30min)/5cycle
Pre-firing test: temperature (maximum rated temperature)/ current (maximum rated forward current)96 hours
High temperature storage: 85℃/72 ~ 1000 hours
LED lamp life test:
More than 1000 hours of Life Test (Life Test), light attenuation < 3% [withered light]
More than 15,000 hours of Life Test (Life Test), light attenuation < 8%
Test Specification of LCD Display
LCD Display, full name of Liquid Crystal Display, is a flat display technology. It mainly uses liquid crystal materials to control the transmission and blocking of light, so as to achieve the display of images. The structure of the LCD usually includes two parallel glass substrates, with a liquid crystal box in the middle, and the polarized light of each pixel is controlled by the rotation direction of the liquid crystal molecules through the voltage, so as to achieve the purpose of imaging. LCD displays are widely used in TV, computer monitors, mobile phones, tablet computers and other devices.
At present, the common liquid crystal display devices are Twisted Nematic (TN), Super Twisted Nematic (Super Twisted Nematic), STN), DSTN(Double layer TN) and color Thin Film Transistors (TFT). The first three kinds of manufacturing basic principles are the same, become passive matrix liquid crystal, and TFT is more complex, because of the retention of memory, and called active matrix liquid crystal.
Due to liquid crystal display has the advantages of small space, thin panel thickness, light weight, flat right-angle display, low power consumption, no electromagnetic radiation, no thermal radiation, it gradually replaces the traditional CRT image tube monitor.
LCD displays basically have four display modes: reflection, reflection transmission conversion, projection, transmission.
(1) The reflection type liquid crystal display itself does not emit light, through the light source in the space into the LCD panel, and then by its reflective plate will reflect the light to the eyes of people;
(2) The reflection transmission conversion type can be used as a reflection type when the light source in the space is sufficient, and the light source in the space is used as lighting when the light is not enough;
(3) Projection type is to use the principle of similar movie playback, the use of projected light department to project the image displayed by the liquid crystal display to the remote larger screen;
(4) The transmission type liquid crystal display completely uses the hidden light source as lighting.
Relevant Test Conditions:
Item
Temperature
Time
Other
High temperature storage
60℃,30%RH
120 hours
Note 1
Low temperature storage
-20℃
120 hours
Note 1
High temperature and high humidity
40℃,95%RH (non-invasive)
120 hours
Note 1
High-temperature operation
40℃,30%RH.
120 hours
Standard voltage
Temperature shock
-20℃(30min)↓25℃(10min)↓20℃(30min)↓25℃(10min)
10cycle
Note 1
Mechanical vibration
—
—
Frequency: 5-500hz, acceleration: 1.0g, amplitude: 1.0mm, duration: 15mins, twice in X,Y,Z direction.
Item
Temperature
Time
Other
Note 1: The tested module should be placed at normal (15 ~ 35℃,45 ~ 65%RH) for one hour before testing
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