The application of two-box thermal shock test chamber in reliability

What is a “two-box thermal shock test chamber”?

As the name suggests, a two-box thermal shock test chamber is equipped with two independent temperature control zones: one for high temperature and the other for low temperature. During the test, the sample is moved rapidly between the two zones by a mechanical device, thus realizing a sharp change in temperature. This method omits the room temperature transition and is suitable for more intense thermal shock testing.

The two-box thermal shock test chamber is mainly used to verify the structural integrity and material adaptability of products under severe temperature sudden change environment, especially suitable for military electronics, aviation devices, automotive components and semiconductor devices for high reliability screening. The two-box thermal shock test chamber consists of high-temperature zone and low-temperature zone, samples in the two areas of rapid movement to complete the thermal shock process, without passing through the room temperature zone, can realize the maximum degree of thermal stress loading.

What are the environments simulated by the two-box thermal shock test chamber?

The two-box thermal shock test chamber can simulate the rapid switching between -70℃ and +180℃. Typical application environments include:

- Limit test for military electronic parts: according to MIL-STD-883H Method 1010.8, the direct switching between high and low temperatures simulates the rapid descent of a flight platform from high altitude to the low-temperature region;

- Thermal cycling test for automotive ignition modules, ECUs, etc.: in accordance with the requirements of ISO 16750-4, the thermal cycling test is performed at the same time as the thermal cycling test for automotive ignition modules. Thermal cycling test for automotive ignition modules, ECUs, etc.: in accordance with ISO 16750-4, the thermal shock condition occurs when the whole vehicle is instantly energized in a low-temperature environment in a plateau;

- Screening of Space Probe Components: NASA uses conditions similar to those of JEDEC JESD22-A104 to verify that the electronic modules remain functionally stable under extreme warming/cooling conditions.

What is the difference between two-box thermal shock test and three-box thermal shock test?

In the three-box thermal shock test chamber, the product in the high and low temperature switching process usually passes through the normal temperature zone first, the application of three-box thermal shock test chamber can be viewed by clicking the blue word. However, the two-chamber thermal shock test chamber is directly in the extreme temperature switching, eliminating the intermediate link. This approach is closer to some special application scenarios, such as satellite modules in orbit, electric vehicles in the extreme cold or high temperature region of the start-up process.

What are the structural advantages of the two-box thermal shock test chamber?

Compared with the three-box thermal shock test chamber, the two-box thermal shock test chamber has the following outstanding advantages:

Shorter changeover time: the switchover of temperature zones is usually completed within 10 seconds;

More compact structure: suitable for use in the laboratory or in small batch trial production stage;

Stronger stress loading: higher impact strength, better able to expose potential defects.

The two-chamber cold and thermal shock tester is commonly used in the design verification testing stage.

Commonly used international test standards

Most international environmental stress screening standards have strict time and temperature control requirements for temperature shock testing. JESD22-A104D, for example, emphasizes the number of cycles (≥500), transition time (<10 seconds) and sample temperature equalization verification. The two-chamber cold and thermal shock tester is able to realize the following standard requirements due to its compact structure, constant temperature and independent control of the two chambers:

According to IEC 60068-2-14 and MIL-STD-883 standards, two-box thermal shock test chambers can meet stringent temperature change rate and transition time requirements to ensure highly repeatable and representative test results. Especially in the high-reliability industry, manufacturers often rely on these international specifications to set up test cycles, such as 500 or 1,000 cycles, to accelerate the exposure of potential failure mechanisms.

Research published in the journal “Microelectronics Reliability” pointed out that the temperature difference of more than 100 ℃ when the rapid impact can best reveal the hidden danger of the BGA package solder joints; and the “Journal of Thermal Analysis and Calorimetry” of an experiment showed that, through the two-box thermal shock test chamber, An experiment in the Journal of Thermal Analysis and Calorimetry showed that high-intensity stress loading through a two-box cold thermal shock test chamber can significantly shorten the failure detection cycle of electronic modules and improve the efficiency of engineering iterations.

Some enterprise users (e.g. Bosch, Huawei, General Motors, Honeywell) have also formulated targeted processes and cycle conditions, and used two-box thermal shock test chamber for batch screening and validation.

Two box thermal shock test chamber test type

TEMAK two-box thermal shock test chamber to improve the effectiveness of the test

1. Professional refrigeration configuration and design process, low failure rate;

2. Ultra-low defrosting times, perfect sealing design, improve the test rate;

3. Multiple compressor protection, compressor long-term low failure;

4. Upper computer remote operation of the test chamber, real-time monitoring of the sample temperature curve.