What is the high and low temperature test? Standards and methods for high and low temperature test items of electronic products

Date：2021-07-26 11:16:00Views：3869

High and low temperature test, also known as high and low temperature cycle test, is one of the environmental reliability tests. The purpose of the test is to evaluate the impact of high and low temperature conditions on the performance of equipment during storage and operation. Basically, all products are stored or operated at a certain temperature. Because products will face a variety of different temperature, humidity, climate and external conditions when they are manufactured, handled or stored. These climates change the physical, mechanical and even chemical properties of the products, which will make the products ineffective and reduce the value or production risk. Therefore, countries all over the world have formulated test specifications for various products for different products, so that the buyer and the seller can reach a consensus and inspect the products during design, R & D, feeding and shipment to ensure that the quality reaches the national standards.

Application fields of high and low temperature test:

1. Computer: computer, display screen, host, computer components, medical equipment and other precision instruments;

2. Electronic communication: mobile phones, RF devices, electronic communication components, etc;

3. Electrical appliances: household appliances, lamps, transformers and other household appliances;

4. Others: packing boxes, transportation equipment, etc.

High and low temperature test method:

Firstly, adjust the box temperature to 25 ℃± 3 ℃ and maintain this value, adjust the relative humidity to 45% ~ 75%, and stabilize the temperature for 2 ~ 6 hours. In the last 1 h, increase the relative humidity in the box to no less than 95%, and keep the temperature at 25 ℃± 3 ℃.

After the stabilization stage, the cycle starts, so that the box temperature continuously rises from 25 ℃± 3 ℃ to 55 ℃± 2 ℃ within 2.5 h ~ 3 h. during this period, except that the relative humidity in the last 15 min is not less than 90%, the relative humidity in the heating stage shall not be less than 95%, so as to cause condensation on the surface of the test sample, but excessive condensation shall not be generated on the large test sample. Then, it shall be maintained in a high temperature and high humidity environment with a temperature of 55 ℃ ± 2 ℃ until 12 h ± 0.5 h from the beginning of the cycle. The relative humidity at this stage shall be (93 ± 3)%, except that it shall not be lower than 90% in the first and last 15 minutes.

Then, within 3 h ~ 6 h, reduce the box temperature from 55 ℃± 2 ℃ to 25 ℃± 3 ℃. The cooling rate for the first 1.5h is 10 ℃ / h, and the relative humidity during this period is not less than 95% except that it is not less than 90% in the first 15min.

After cooling, the temperature shall be maintained at 25 ℃± 3 ℃ and the relative humidity shall not be lower than 95%. 24 hours from the beginning of the cycle is a cycle.

High and low temperature test items and standards:

1. High temperature test

High temperature test is used to determine the adaptability of products to storage, transportation and use under high temperature climate and environmental conditions. The severity of the test depends on the temperature of the high temperature and the duration of exposure.

Reference test standards: GB / T 2423.2, IEC 60068-2-2, ieia 364, mil-std-810f, etc.

2. Low temperature test

Low temperature test is used to determine the adaptability of products to storage, transportation and use under low temperature climate and environmental conditions. The severity of the test depends on the low temperature and exposure duration.

Reference test standards: GB / T 2423.1, IEC 60068-2-1, EIA 364, mil-std-810f, etc.

3. Temperature impact test

Temperature shock test is to determine the adaptability of products to storage, transportation and use in the climate environment with rapid temperature change. The severity of the test depends on high / low temperature, dwell time, number of cycles.

Reference test standards: iec60068-2-14, GB2423 22、GJB150. 5, etc

4. Rapid temperature change test

Rapid temperature change test is used to determine the adaptability of products to storage, transportation and use under the climate environment of rapid or slow change of high temperature and low temperature.

The test process takes normal temperature → low temperature → low temperature residence → high temperature → high temperature residence → normal temperature as a cycle. The severity of temperature cycle test is determined by high / low temperature range, residence time and cycle number.

Reference test standards: GB / T 2423.34, IEC 60068-2-38, jb150 5, etc.

5. Alternating damp heat test

High and low temperature alternating damp heat test is a necessary test item in aviation, automobile, household appliances, scientific research and other fields. It is used to test and determine the parameters and performance of electrical, electronic and other products and materials after high temperature, low temperature, alternating damp heat or constant test. Test reference standards: GB / T 2423.1, GB / T 2423.2, GB / T 2423.3 and GB / T 2423.4.

It is worth noting that IC chip high and low temperature test is a test chamber simulating the environment. When in use, there may be various end environments in the test chamber, such as low temperature, high temperature and high pressure, high temperature and high humidity and other special conditions. In the middle of the high and low temperature test run of semiconductor chips, if it is not very necessary to open the test box door, do not open the test line door. If it is necessary to open the test box door in the middle, please take relevant protective measures and open the test box door in a correct way.