Description:

Cyclic damp heat test can be divided into two types: equipment-level cyclic damp heat test, represented by GB/T2423.4 and GJB150.9, and device-level cyclic damp heat test for electrical components, microelectronic devices, etc., represented by GJB 360B, GJB 548B, and GB/T 2423.34.

Scope of Application: 

Electronics, components, circuit boards, and other electrical and electronic products.

Image of Cyclic Damp Heat Test:

Fig. 2 Equipment-level cyclic damp heat test curve

Image of Cyclic Damp Heat Testing Equipment:

Equipment-level Cyclic Damp Heat Test:

Common Severity Levels:

The combination of high temperature and cycle times determines the severity of the alternating damp heat test. GB/T2423.4 recommends a high temperature of 40°C (with cycle times of 2, 6, 12, 21, or any combination of these) or 55°C (with cycle times of 1, 2, or 6, or any combination of these). GJB1509 specifies a high temperature of 60°C with a minimum of 10 test cycles.

Test Procedure (Take Step 3 to 6 as a cycle)

Test Interruption Processing:

In case of a test interruption due to a sudden power failure or other special circumstances during the test, the following actions are recommended:

1)If the environmental conditions inside the alternating damp heat test chamber did not exceed the allowed error range during the interruption, the time of interruption should be included as part of the total test time.

2)If the environmental conditions inside the chamber dropped below the lower limit of the allowed error range during the interruption, the test should be restarted from the end point of the previous valid cycle, excluding the interrupted cycle.

3)If an interruption occurs during the test, it is advisable to stop the test and restart with a new sample. If it is determined by relevant technical personnel that the test conditions exceeding the requirements will not directly cause damage to the sample or if the sample is a repairable product, the environmental conditions inside the chamber can be restored to the required conditions and the test can continue. If the sample fails in subsequent tests, the test results should be considered invalid.

Device-level Cyclic Damp Heat Test:

Common Severity Level:

Temperature: 65°C, humidity: 90-100% RH, number of cycles: 10.

Test Procedure (Take 37 to 97 as a cycle):

Test Interruption Processing:

In case of a test interruption due to a sudden power failure or other special circumstances during the test, if no more than one accidental test interruption occurs before completing the specified number of cycles (excluding the following cycle), that cycle can be repeated. If an accidental test interruption occurs during the following cycle, it is required to repeat that cycle and perform an additional uninterrupted cycle. Any interruption lasting more than 24 hours requires restarting the test from the beginning to the end.