The Difference Between Thermal Shock Test Chamber And Rapid Temperature Change Test Chamber

When it comes to thermal shock test chamber and rapid temperature change test chamber, people may be a little confused about the two types of equipment and the corresponding thermal shock test and rapid temperature change test. Today, let's discuss the relationship between the two.

What is thermal shock testing?

The thermal shock test, also known as a temperature shock test or high/low temperature thermal shock test, involves suddenly exposing a sample to a low-temperature environment. This is considered a thermal shock. It primarily verifies the test sample's resistance to thermal expansion and contraction. It is a destructive test.

What is a rapid temperature change test?

A rapid temperature chage test, as the name suggests, is a test in which the temperature changes rapidly.

The core difference between thermal shock testing and rapid temperature change testing lies in the rate of temperature change.

1. Thermal shock testing causes a sample to plummet from 150°C to -40°C or even lower in a very short time,this is also the advantage and characteristic of thermal shock test chamber; rapid temperature change testing, on the other hand, involves a continuous rise or fall of temperature at a set rate. The time and rate of temperature change are significantly different between the two.

2. Thermal shock testing involves extremely rapid temperature switching, typically completing the transition from high to low temperature in just 3 to 5 minutes; hence, it is also called high and low temperature shock testing.

3. Temperature cycling testing has a relatively slower transition speed, generally with a heating/cooling rate of approximately 1–3°C per minute.

4. Furthermore, conventional thermal shock testing usually does not involve humidity control, while temperature cycling testing can be equipped with humidity control as needed.

The curves clearly show that the rate of temperature change during the temperature cycle is linear, while the rate of temperature shock is nonlinear.

Thermal shock mainly occurs during the research and development design and trial production stages;

while rapid temperature changes mainly occur during the mass production stage.

Rapid temperature change testing commonly occurs in the powered operating mode, while thermal shock testing typically takes place in the non-operating mode or a dormant state (less common). Thermal shock testing of assemblies requires pre-measuring the time it takes for the component's internal temperature to reach the required level, i.e., the stabilization time shown in the diagram above. Rapid temperature change testing does not require this time measurement. Long-cycle thermal shock testing is also frequently used for PCB defect verification, such as the thermal shock durability test in Ford CETP, where the sample is a PCBA board.

A. The thermal shock test chamber is specifically designed for performing thermal shock tests, and its structural design differs significantly from that of the rapid temperature change test chamber. This equipment has two temperature zones: a high-temperature zone and a low-temperature zone. Based on the chamber structure, thermal shock test chamber can be divided into two types: two-chamber and three-chamber. The three-chamber thermal shock test chamber uses a layout of three independent chambers: a high-temperature zone, a low-temperature zone, and a test zone. During the test, the sample to be tested is placed in the test zone, and alternating airflow from the high-temperature zone and the low-temperature zone creates alternating impacts on the sample in the test zone, thus achieving the thermal shock effect.

B. The rapid temperature change test chamber is different from the thermal shock test chamber. It has only one chamber, unlike the thermal shock chamber which has two or three temperature zones. However, this chamber is larger than a regular high and low temperature test chamber because a high-power compressor is required to achieve rapid temperature rise and fall.

Common reference standards for thermal shock: GB/T 2423.22-2012, IEC60068-2-14:2009, GB/T 28046.4-2011;

Reference standards for rapid temperature change: GB/T2423.22, IEC60068_2_14.