Temperature and Humidity Chamber Driven Temperature Cycling Tests

 In the field of reliability engineering, temperature and humidity chambers are the core equipment for realizing temperature cycling tests. By precisely controlling the rate of temperature rise and fall and humidity fluctuations, this type of equipment can simulate the harsh environment from the polar cold to the desert heat, to provide a scientific basis for assessing the thermo-mechanical stability of materials and devices.

I. The temperature and humidity test chamber temperature cycle mechanism

Temperature and humidity test chamber through the refrigeration/heating system and humidity regulation module synergy, to achieve programmable temperature fluctuations cycle:

Thermal stress generation: box body internal configuration of platinum resistance sensor real-time monitoring of the cavity temperature, with the PID algorithm will be the temperature deviation control of ± 0.5 ° C

Coefficient of expansion simulation: When the temperature and humidity chamber in the -65 ° C to +150 ° C interval cycle, the aluminum alloy and the FCC When the temperature and humidity chamber cycles between -65℃ and +150℃, the CTE difference between aluminum alloy and FR-4 substrate can reach 18ppm/℃, triggering interfacial shear stress

Energy transfer optimization: the new temperature and humidity chamber adopts the compound stacked refrigeration technology, which makes the temperature rise and fall rate break through 15℃/min, and is three times higher than the traditional equipment.

The data of a space academy shows that the satellite bracket, which completes 2,000 temperature cycles in the temperature and humidity chamber (-55℃ ↔ 125℃), has its fatigue life predicted by the PID algorithm. A space institute data show that the fatigue life prediction accuracy of the satellite bracket after 2000 temperature cycles (-55℃↔125℃) in the temperature and humidity test chamber is 92%.

II. The key parameters of the temperature and humidity test chamber system

Temperature range expansion

Military-grade temperature and humidity test chamber up to -70 ℃ ~ +180 ℃, the use of liquid nitrogen-assisted refrigeration and silicon-carbon rod heating technology

Automotive electronics testing commonly used three-box temperature and humidity test chamber to achieve the -40 ℃ → 85 ℃ → 150 ℃ of the step cycle

Temperature rate control

Semiconductor industry requires temperature and humidity test chamber with a temperature ≥ 20 ℃ / min of the ability to change temperature, through the scroll compressor and dual-box temperature controller. Semiconductor industry requires temperature and humidity test chamber has ≥ 20 ℃ / min variable temperature capacity, through the scroll compressor and two-stage refrigeration to achieve

Precision optical device testing needs to be limited to 5 ℃ / min or less, to prevent thermal distortion of the lens

Humidity coupling mechanism

In the high temperature of 85 ℃ section, temperature and humidity test chamber can maintain 95% RH humidity, simulating the environment of the tropical rainforest

Equipped with dew-point sensors temperature and humidity test chamber can be precisely controlled in the -40 ℃ low-temperature frost

A new energy automobile enterprise case shows that The case of a new energy automobile company showed that after 1000 cycles (-40 ℃ ↔ 85 ℃, 95% RH) of the temperature and humidity chamber, the peel strength of the battery pack sealant decreased by 37%, and the data guided the optimization of the adhesive formula.

III. The temperature and humidity test chamber of the engineering failure analysis

solder joints fatigue monitoring

Temperature and humidity test chamber built-in micro-ohmmeter can detect the resistance change of the BGA solder joints, when the resistance fluctuation of > 15% is judged to be a potential failure

Infrared thermal imaging module captures the QFN package in the temperature and humidity cycle of the maximum thermal stress is concentrated in the four corners of the pads

M aterial interface analysis

Through the temperature and humidity test chamber coupled with scanning acoustic microscope, it was found that the PCB in the 62μm substrate-copper foil delamination after 300 cycles

Atomic force microscope observation shows that epoxy resin produces nanoscale creep depressions under temperature and humidity alternating environments

Sealing performance validation

Temperature and humidity test chamber with integrated helium mass spectrometry leak detector, which can detect trace leaks of 1×10-⁸ mbar-L/s

Automotive light clusters develop 0.3mm leaks after temperature and humidity cycles Permanent deformation of 0.3mm silicone seal after temperature and humidity cycle, traced back to the 827th cycle through the box deformation recording system

IV. Technical Evolution of Temperature and Humidity Test Chamber

Multi-stress coupling system

The third generation of temperature and humidity test chamber integrates shaking table (5-2000Hz) and salt spray module to realize four-dimensional testing of temperature-humidity- vibration-corrosion

The test chamber using graphene heating film will increase the temperature uniformity from ±2℃ to ±0.5℃

Intelligent monitoring system

Temperature and humidity test chamber based on digital twin technology can predict the material performance decay curve after 2000 cycles

Chamber equipped with machine vision can automatically identify 63 typical failure modes on the specimen surface

Energy-saving and environmentally friendly design

Temperature and humidity test chamber adopting R452B environmentally friendly refrigerant, the GWP value of which is reduced by 78% compared with the traditional medium

The heat recovery system converts 80% of the waste heat to the chamber. Heat recovery system can convert 80% of the waste heat into box defrost energy

A chip sealing and testing enterprise application cases show that the temperature and humidity test chamber configured with AI algorithms will shorten the test cycle by 40%, and at the same time will reduce the misjudgment rate from 12% to 3.2%.

V. Temperature and humidity test chamber standard system

International norms

IEC 60068-2-14:2009 stipulates that the temperature gradient of the temperature and humidity test chamber ≤ 1 ℃ / min;

MIL-STD-883K Method 1010.9 requirements for military devices in the temperature and humidity test chamber to complete the 500 times -65 ℃ ↔ +150 ℃ cycle.

Industry Applications

In-vehicle electronics follow the AEC-Q100 standard, which requires 1000 cycles of -40°C ↔ +125°C in a temperature and humidity chamber

Photovoltaic modules follow IEC 61215, which requires 200 cycles of -40°C ↔ +85°C in a temperature and humidity chamber

Data Reliability

NIST-traceable temperature sensor ensures that the uncertainty of the temperature and humidity chamber measurements is ≤0.3°C Daily execution of chamber uniformity validation in accordance with JJF 1101-2019 calibration specification

As the ultimate examination center for material environmental adaptability, the temperature and humidity test chamber is evolving towards multi-field coupling, intelligent prediction, and green and low-carbon direction. Its core position in temperature cycling test is not only reflected in the continuous breakthrough in equipment accuracy, but also in the ability to analyze the depth of the failure mechanism of products. With the explosive development of the fifth generation of communications, new energy, air and space technology and other fields, the temperature and humidity test chamber will assume a more important technical support role.