Tough Out: Can Your Product Outlast the Thermal Shock Test?

What is Thermal Shock Test?

The adaptability of a product towards the rapid and extreme variation in temperature will need to undergo a test for its durability called the Thermal Shock Test.
 
Any kind of product or equipment could be exposed to contrasting weather conditions, either too hot or too cold.

"The adaptability of a product towards the rapid and extreme variation in temperature will need to undergo a test for its durability called the Thermal Shock Test."

​​These kinds of exposure could change or alter the properties of a product and weaken its ability to hold itself together which can cause it to crack, break, or bend.
 
Take vinyl leather for example, it usually comes in a form of a bag or a coat.
 
When vinyl leather is exposed to altering weather in rapid succession, the leather property chips, thus altering its structural properties, strength and longevity.

To resolve this issue, manufacturers executes a Thermal Shock test to find out the extent to which a product can outlast weather changes.
 
This execution of the Thermal Shock test involves a rapid change of extreme temperature from either hot to cold and vice-versa.
 
This test usually uses 15 °C per minute temperature or higher, a testing temperature for goods or products that are subject to transport or distribution.
 
Products may be military parts and equipment, aerospace parts, product packaging and even electronic devices that are made for rough use.
 
Having these products undergo Thermal Shock Test could really help determine its capability to withstand rapid changes in weather.
 
Imagine if an aircraft part cannot withstand the rapid change in weather and it cracks and blows the whole part which could cause a big destruction.

Imagine if an aircraft part cannot withstand the rapid change in weather and it cracks and blows the whole part which could cause a big destruction.

​Test Standards That Are Applicable for Thermal Shock

​MIL-STD-810

This is a US Military Standard used by altering a product or equipment’s ecological design and test limits of the situation, circumstances that the product will have to go through in its supposed lifetime.

Although this has been fashioned primarily for military use, it is also widely used on commercial products.
 
This test uses thermal shock test chamber wherein the effects of the environment is being replicated or simulated on the equipment rather than the manufacturers modelling the environmental conditions commonly surrounding the product themselves.
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MIL-STD-202 

This standard is used to gauge how long an electronic or electrical component withstand the number of natural, electrical and physical elements surrounding military operations that may be damaging or harmful to said products.
 
IEC 60068-2-14

This international standard organization is called the International Electrotechnical Commission. They formulate and circulate a list of electrical or electronic related technologies.
 
This Standard tests an equipment and its components capacity to endure in the swift change of the temperature surrounding it.
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The duration to which an equipment or product is to be exposed in this test will vary depending on the property of the equipment.

Example of Thermal Shock Test profile

Purpose of Thermal Shock test

​Various industries have had the increasing need to perform the thermal shock due to factors that follows:

- Reduction of parts and minimization of equipment make them more vulnerable to heat

- Production processes may cause extreme heat, such as reflow soldering

- Higher product precision demands are causing heat stress during production

- New innovations with the automotive industry aiming for lighter yet stronger parts for vehicles will require more information in how these new parts can endure extreme changes in temperature
 
- Rapid and extreme change in temperature, specifically within the engines’ compartments and the machineries under the hood.
 

"...aiming for lighter yet stronger parts for vehicles will require more information in how these new parts can endure extreme changes in temperature."

​Performing Thermal Shock Test

​When thermal shock testing is being performed, it is important to first carefully identify the upper and lower temperatures.
​
According to the Coffin-Manson equation, the larger the difference is between the temperatures on the test chamber compared to the normal use temperature of the product will result in the higher acceleration factors.
 
Having said that, it is best to choose the correct temperature limits that does not surpass the operating limits of the product or its property limits.
 

"...it is best to choose the correct temperature limits that does not surpass the operating limits of the product or its property limits."

​As an example, if the upper temperature chosen exceeds or goes beyond the melting point of any of the components or material of a product, the test results will most probably be inaccurate.
 
The main idea is to ensure that the temperatures (low and high) are properly measured during the test and ensure that a careful monitoring is established and the placement of the thermocouples around the samples or the product are just right.
 
The thermal mass of the product or sample, the number of samples, and the flow of air around the sample (that are highly dependent on the spacing of the samples in the chamber) are factors that can influence the test parameters.
 
How long a product or sample will need to be exposed to each temperature should be included as well in the test requirement as well as the tolerances of the product around the low and high temperatures.
 

"How long a product or sample will need to be exposed to each temperature should be included as well"

​The test methods can specify the minimum rates of temperature change. The products exposed to thermal test can either be powered or unpowered.
 
For powered products, longer cables will need to be prepared so the cables can be reached outside the chamber but can fit through the chamber pothole.
​

Types of Thermal Shock Chamber

​
​Generally thermal sock chamber can be classified into 2 types, ie 3-zones and 2-zones shock chamber. This classification is defined by the structure of the chamber.
 
Thermal shock chamber can be categorized by the test medium it uses also, ie air and liquid. This will not be discussed in this article. We may share more about it in future.
 
Air to air type thermal shock chamber is widely used. We will only touch on this type of chamber here. 

3-zones Thermal-Shock Chamber

The three zone thermal shock chamber is appropriate for testing a whole set of products, materials and parts, as well as components that are exposed to rapid changes in temperature.
 
In hindsight, this means that this chamber is made for larger products or samples. 

The three zone thermal shock chamber comprises of the Low Temperature area for the pre-cooling, the High Temperature area for pre-heating and the test area where the sample is placed.

​I​n this testing, the samples are placed in the chamber (test area) while the air temperature rapidly increases and decreases (rapid cooling and heating), independent wind path switching mode is then adopted to transfer hot and cold air to test area making sure that the switching of temperature is swift with the product or sample resting still during the process.
 
In this process of the whole chamber is cooled down and then heated up, the chamber temperature change in a slower rate compared to two zones thermal shock chamber.
 
2-zones Thermal-Shock Chamber

The Two Zones Thermal Shock Chamber is designed for smaller products or samples. It works on an elevator mechanism which also has a limit on the weight of a product or sample for testing.
 
This chamber has two separate chambers (hot and cold chambers), the elevator mechanism is used to transport the product or sample between two or more testing chambers that are placed in a portable basket.

​A mobile gondola is used to carry the product from the cryogenic tank then to the high temperature tank to accomplish a quick or swift rate of change in the air temperature. 

TestLabs' Thermal Shock Testing Service and Thermal Shock Test Chamber 

​TestLabs.my performs accredited Thermal Shock Testing according to MIL-STD-810 and IEC standards. We specialize in customizing different testing to meet special customer requirements.

On top of that, TestLabs.my supply quality Thermal Shock Test Chamber at affordable price and provide after sales support for all our environmental test equipment.

For more advise on how we can test and qualify your products please contact us and leave us a message.