test project

 rapid temperature change test

reference standard

      GB/T 2423.22-2012， IEC 60068-2-14-2009

 capabilities

 Temperature range: -70℃~150℃;800×600×850mm
 Temperature transition rate: ≤ 15℃/min

The rapid temperature change test is used to determine the adaptability of products to storage, transportation, and use in a rapidly or slowly changing climate environment at high and low temperatures. The test process consists of normal temperature → low temperature dwell → high temperature dwell → normal temperature. The severity of the temperature cycle test is determined by the high/low temperature range, dwell time and number of cycles.

The testing process is usually as follows:

1. The test process engineer conducts a visual inspection on the test samples and inspects their electrical and mechanical properties;

2. Put the non-electrified test sample into the test chamber according to its normal working position or state;

3. When the actual test sample is used with a specific mounting frame (fixture), these devices should be used together for testing. If power is required during testing, the test samples will be electrified or electrically loaded according to relevant standards to allow the product to be processed in operation. The equipment will be adjusted to the required high and low temperature conditions according to standard regulations or customer requirements. Maintain at each temperature point for a specified time;

4. After the conditional test is over, the test sample will enter the recovery procedure. If the test sample is in running or loaded state during the conditional test, it should be disconnected from the power supply or unloaded from the load before entering the recovery procedure, and the sample should be placed in standard atmospheric conditions. Maintain enough time to stabilize its temperature for at least 1 hour;

5. Conduct power-on inspection functions or mechanical properties during the recovery period of the test samples according to relevant standards or customer requirements.

Fault performance and scope of application

Rapid temperature change test is one of the mandatory test items for related products in the fields of aviation, automobiles, home appliances, scientific research and other fields. The failure manifestations of samples during the test mainly include the following:

1. Various micro-cracks on the coating, material or wire ends expand;

2. The joints with poor bonding are loose;

3. Loose joints with improper screw connection or riveting;

4. Deformation and stress caused by different thermal expansion coefficients of materials reduce the insulation of sealing materials;

5. The press-fit joints with insufficient mechanical tension are loose;

6. The resistance of the brazing contact parts increases or causes an open circuit;

7. Failure of moving parts and seals.