How do companies know whether their devices can withstand radical temperature changes and still function properly? Would you fly a plane if you weren’t confident all its components were sufficiently tested against extreme thermal conditions beforehand?
Thermal shock testing is the process of rapidly transferring a product between two temperature extremes to evaluate its durability, identify potential breaking points, and validate overall product reliability.
In an accelerated environment, this testing mimics the wear and tear a product will encounter in usual conditions or standard use. Rapid temperature changes generate thermal stress that can cause physical elements to shatter, crack, or bind in unintended ways.
How Does Thermal Shock Testing Work?
The core thermal shock test method works by placing the device under testing (DUT) inside a basket that automatically moves between hot and cold zones. Transfer time between zones is usually under 10 seconds, with the temperature of each zone managed by either an air-to-air or liquid-to-liquid system.
While air is more standard, the alternative involves injecting liquid nitrogen (LN2) or carbon dioxide (CO2) into the test chamber to expand achievable temperature ranges and increase the temperature change rates. This is sometimes called a “liquid boost.” A LN2 boost can rapidly lower the temperature to as low as -185°C (-300°F), while CO2 can lower the chamber's internal temperature almost instantaneously to around -73°C (-100°F).
Since many components that undergo temperature shock testing are used in the aerospace and defense industries, rigorous standards must govern the process to ensure DUTs are rigorously tested, including MIL-STD 883K Method 1010.9, MIL-STD 202H Method 107, MIL-STD-202G, and MIL-STD-883G. Additional international standards such as IEC 60068-2-14 and JEDEC JESD22-A106 also define thermal shock testing procedures for electronics and semiconductor applications.
What Industries Conduct Thermal Shock Testing?
A thermal shock test is a great tool for determining the resilience of electronic components, electromechanical assemblies, plastic, and mechanical products across a wide range of industries. Aerospace environmental testing and automotive testing rely heavily on this process, as do medical device, consumer electronics, and defense manufacturers.
Consider the temperature variations the parts of an airplane experience as temperatures change as altitude increases or decreases, or the trauma inflicted on a GPS device used in wilderness terrain by field researchers. The ability of these electronics to function properly is often a matter of life and death.
How Is Thermal Shock Testing Different from Thermal Cycling?
Both methods evaluate how products respond to temperature variation, but the mechanism and intent are different. Thermal cycling raises and lowers the temperature gradually, usually 5°C to 15°C per minute, to simulate the long-term effects of seasonal or operational temperature shifts. Meanwhile, thermal shock testing transfers the product between temperature extremes in seconds, generating far more aggressive thermal stress.
That rapid transfer is what makes the difference. Materials expand and contract at rates determined by their coefficient of thermal expansion. So, when that expansion happens instantaneously across bonded materials with mismatched coefficients, the resulting stress is significantly higher than what a gradual cycle might produce. This is why thermal shock testing tends to reveal different failure modes than cycling: cracked solder joints, delamination between material layers, and package fractures that slower testing may never surface.
A qualified thermal shock testing lab will usually run both tests as needed, but thermal shock is the faster, more aggressive method for identifying structural and mechanical weaknesses before they reach the field.
About Thermal Shock Chambers
You could conduct thermal testing using multiple chambers. Say you have two temperature chambers. So long as they’re close to each other—for example, if they were stackable models—you could condition one to reach the extreme heat level and the other the extreme cold, then transfer the DUT between each.
However, a purpose-built thermal shock test chamber will deliver far more consistent and compliant results. Since the military standards referenced above are exact, deviating from the specifications at any point will require you to document the deviation and explain how you compensated for it.
That isn’t an issue with a chamber optimized for thermal shock testing.
The best modern thermal shock chambers—including those designed for air-to-air thermal shock testing—use heavy-gauge steel exteriors and stainless steel interiors with a layer of highly efficient, low K-factor thermal insulation. This helps them consistently maintain high efficiency and temperature performance.
These chambers feature two zones, one maintaining a cooling zone while the other holds a heating zone.
The cooling zone includes a standard cascade refrigeration system typically designed with speedy recovery rates. Air cooling is less efficient but costs less while liquid-cooling options are a bit more complex, more efficient, and more expensive.
The heating zone is all-electric and consists of low-watt-density resistance heaters with ceramic cores. This extends their life, with limited downtime. Industry-leading chambers can support temperatures up to 220°C (428°F), with heaters operating independently for highly responsive temperature control.
Some models even offer a third zone between these two extremes if your testing calls for an ambient phase. The DUT moves between the chambers in a pneumatically controlled basket, containing its own sensor so engineers can monitor the product in addition to the temperature in each zone. Temperature data is collected throughout testing in all three areas, with soak time and recovery rates tracked to ensure accurate, repeatable results.
All this combines for a reliable and precise process that ensures the most essential electronic components used in modern life are safe and durable, not only for aerospace and defense industries but for the general public as well.
Associated Environmental Systems manufactures industry-leading thermal shock chambers to empower businesses who need guarantees their products can withstand rapid changes in temperature. Contact AES to learn more.
FAQ: Thermal Shock Testing
What is the main purpose of thermal shock testing?
The main purpose of thermal shock testing is to determine if a product can withstand sudden, extreme temperature changes without physical damage or performance degradation. By compressing years of real-world thermal stress into a controlled test cycle, engineers can identify weaknesses in materials, bonds, and seals before production.
How is thermal shock testing different from thermal cycling?
Thermal shock testing transfers products between hot and cold zones in seconds, while thermal cycling raises and lowers the temperature at a controlled rate of a few degrees per minute. Thermal shock produces more aggressive mechanical stress and is better suited for exposing structural failure modes like cracking and delamination.
What failures can thermal shock testing reveal?
Thermal shock testing reveals failure modes that may not surface during standard environmental testing. Common findings include cracked solder joints, fractured ceramic substrates, delamination between bonded layers, seal degradation, and broken wire bonds in electronic components.
Which standards are commonly used for thermal shock testing?
The most widely referenced standards for thermal shock and temperature shock test procedures include MIL-STD-810 Method 503, MIL-STD-883 Method 1010/1011, IEC 60068-2-14, and JEDEC JESD22-A106. Choosing the right standard depends on the industry, product type, and geographic market.
What test parameters affect thermal shock severity?
The severity of a thermal shock test depends mostly on the temperature delta between hot and cold zones, the transfer time between zones, the soak time at each extreme, and the total number of cycles. Wider temperature ranges and faster transfers produce more aggressive stress.
What industries use thermal shock testing?
Industries that rely on thermal shock testing include aerospace, defense, automotive (especially EV), consumer electronics, medical devices, telecommunications, and energy storage. Any industry producing products that will encounter rapid temperature changes during use, storage, or transport will benefit from this type of testing.
What is the difference between air-to-air and liquid-to-liquid thermal shock testing?
Air-to-air thermal shock testing moves the product between separate hot and cold air chambers and is the most common method for electronics and general-purpose testing. Liquid-to-liquid testing uses fluid baths to transfer heat, achieving faster temperature transitions and more severe stress. The liquid method is typically reserved for applications that require the most aggressive thermal gradient.
