The Type of Thermal Shock Test Chamber
Unfortunately, many people use the same name to refer to different tests. Thermal shock is one of those. Let me elaborate:
Definitions:
1. Alternately dipping the product in hot and cold liquids. More precisely, this should be referred to "liquid-to-liquid thermal shock".
2. Changing the air temperature as quickly as possible in a single chamber. This we would recommend calling "thermal cycling" or "stress screening" and isn't truly thermal shock.
3. Moving the product from a hot to a cold chamber or other sudden change of the air temperature. This is "air-to-air thermal shock" or "two-zone thermal shock".
Sometimes during transfer as described in 3, there is an intermediate step of exposure to room temperature. This is done to allow manual transfer of the product. This is called a "three-zone thermal shock". Mil-Std 202F method 107G allows such a step, for example.
So, from the above list, you can see the variations in what people commonly call "thermal shock". It should also be noted that some specifications call for "thermal cycling" which is actually "air-to-air thermal shock".
With thermal shock tests, there are also several ways to define and measure the performance. Thermal shock tests focus on "recovery time", or how long it takes to stabilize after the switch.
Reference Standard:
GB/T 2423.1-2008
GB/T 2423.2-2008
GB/T 10592-2008
GB/T 150.3A-2009
GB/T 360A-96
