Definition

Infrared PCBA (Printed Circuit Board Assembly) thermal shock test is a reliability test. It is mainly used to evaluate the tolerance of PCB in the environment of rapid temperature change.

Test purpose

Check solder joint reliability: In the manufacturing process of PCB, solder joints connect various electronic components and printed circuit boards. Thermal shock can cause the solder joint to undergo expansion and contraction processes. Through the thermal shock test, it is possible to see whether the solder joint will crack, loosen and other problems under such a sharp change in temperature. For example, in the PCBA of some consumer electronic products, such as the mobile phone motherboard, if the quality of the solder joint is not acceptable, the circuit may be broken after thermal shock, resulting in the failure of some functions of the mobile phone.

Evaluate component performance changes: The performance of electronic components may be affected when the temperature changes. For example, the capacitance value of a capacitor may change with a sharp change in temperature. Thermal shock testing can help determine whether these components can function properly under extreme temperature change environments and whether the performance variation is within allowable limits.

Check material compatibility: PCBA is composed of a variety of materials, including circuit board materials, electronic component packaging materials, etc. Different materials have different thermal expansion coefficients, and rapid temperature changes may lead to problems in the interaction between materials, such as delerination and rupture. Thermal shock testing can check the compatibility between these materials.

Test procedure

Equipment requirements: Thermal shock test chamber is usually used for testing. The test chamber can quickly switch between high and low temperatures, and can accurately control the rate and range of temperature changes.

Test parameter setting: including setting the high temperature value, low temperature value and the number of cycles of temperature change. Generally, the high temperature can be set to about 125 ° C, and the low temperature can be set to about -40 ° C. The number of cycles may be set to dozens or even hundreds of times according to the use environment and requirements of the product. The timing of each cycle also needs to be set appropriately, such as the time interval between high temperature to low temperature and back to high temperature.

Test sample placement: The PCBA sample is placed in the specified position in the thermal shock test chamber to ensure that it can be fully affected by temperature changes and avoid mutual interference between samples.

Evaluation of test results

Visual inspection: After the thermal shock test is completed, the visual inspection of the PCBA is performed first. Look for obvious physical damage such as component displacement, solder joint falling off, and circuit board delamination.

Electrical performance test: Use professional test equipment, such as multimeter, oscilloscope, etc., to test the electrical performance of PCBA. Check whether the circuit can be normally conducted, and whether the electrical parameters of each component are still within the qualified range. For example, whether the power supply line can still be normally supplied, whether there is signal distortion in the signal transmission line, and so on.

In a word, PCBA thermal shock testing is of great significance to ensure the quality and reliability of PCBA products. By simulating the extreme temperature change environment, possible defects in product design, material selection or manufacturing process can be found in advance, so that the product can be improved and optimized before it is formally put into use. This helps to reduce the failure rate of the product in the actual use process, improve the stability and service life of the product, and enhance the competitiveness of the product in the market. Whether in the field of consumer electronics, industrial control field or automotive electronics and other fields, reliable PCBA thermal shock test is one of the key links to ensure the normal operation of the entire electronic system, which lays a solid foundation for the stable operation of electronic equipment.