Difference Between Thermal Shock Test and Rapid Temperature Change Test Author：LINPIN Update Time：2025-05-13 Source：LINPIN What is a Thermal Shock Test? A thermal shock test, also known as a temperature shock test or high-low temperature thermal shock test, simulates the drastic temperature changes a product may experience during design, development, production, transportation, installation, and usage. It primarily evaluates the resistance of the test specimen's structural components to thermal expansion and contraction. To some extent, the thermal shock test is considered a destructive test. What is a Rapid Temperature Change Test? The rapid temperature change test is part of the Environmental Stress Screening (ESS) test, an efficient method for improving product reliability. Environmental Stress Screening (ESS) is a process and method used to identify and eliminate early failures caused by manufacturing processes and components. It involves applying reasonable environmental and electrical stresses to products at various levels (from components upwards) to expose latent defects, turning them into detectable failures for correction and replacement. ESS is a non-destructive testing process, serving as a manufacturing technique. Differences Between Thermal Shock Test and Rapid Temperature Change Test Different Testing Purposes The thermal shock test chamber is essential for industries such as metals, plastics, rubber, and electronics. It tests material structures or composites to detect chemical changes or physical damage caused by thermal expansion and contraction after repeated extreme temperature fluctuations. Typically, two-zone or three-zone thermal shock test chambers are used. The rapid temperature change test applies external environmental stresses to expose early failures in electronic products caused by defective components, manufacturing processes, or other issues during R&D, design, and production. It uses a rapid temperature change test chamber (also called an ESS environmental stress screening chamber) to screen for climatic, thermal, or mechanical stresses that may lead to premature failures. Different Testing Phases Thermal shock tests are mainly conducted during the R&D, design, and prototyping stages. Rapid temperature change tests are primarily used in mass production stages. Different Test Objects Thermal shock test chambers are mainly used to test material structures or composites, with the most common applications being electronic components or assemblies (e.g., PCBA, IC). Rapid temperature change tests are suitable for electronic products at the component, assembly, and device levels. Different Test Structures A thermal shock test chamber has two or three temperature zones (high-temperature and low-temperature zones). Two-zone chambers use a moving mechanism (e.g., a hanging basket or threaded bearings) to shuttle test samples between zones, while three-zone chambers have separate high, low, and test zones, using airflow to alternate temperature impacts. A rapid temperature change test chamber has only one zone, where temperature changes are achieved by heating or cooling. Due to its fast rate of temperature change, it is called a rapid temperature change test chamber, though it cannot match the instantaneous switching of a thermal shock chamber. Different Temperature Change Rate Requirements Thermal shock tests require temperature changes to be completed within 5 minutes (from one extreme to another), with very fast switching rates. Some standards require the product surface temperature to recover within 15 minutes. The process is nonlinear. Rapid temperature change tests complete heating or cooling within a specified time, either linearly or nonlinearly. For example, a chamber ranging from -40°C to 80°C may cool at 5°C per minute (taking 24 minutes), which is slower than a thermal shock chamber but faster than a standard high-low temperature chamber (typically 1°C per minute). Some rapid temperature change chambers can achieve rates of 10°C–30°C per minute, with controllable rates. Different Failure Modes Thermal shock failures are caused by material creep and fatigue damage, also known as brittle failure. Rapid temperature change failures are caused by material fatigue. Different Common Failure Phenomena Thermal shock failures include deformation or cracking of components, insulation layer failure, jamming or loosening of moving parts, changes in electrical/electronic components, and condensation or frost causing malfunctions. Rapid temperature change failures include expansion of micro-cracks in coatings/materials/wires, loosening of poorly bonded joints, relaxation of improperly fastened screws/rivets, stress-induced deformation due to mismatched thermal expansion coefficients, reduced insulation in sealing materials, loosening of poorly fitted press joints, increased contact resistance or open circuits in weak solder joints, and malfunctions in moving/sealing parts. Common Reference Standards Thermal Shock Test Standards: GB/T 2423.22-2012 IEC 60068-2-14:2009 GJB 150.5A-2009 GB/T 28046.4-2011 Rapid Temperature Change Test Standards: GB/T 2423.22 IEC 60068-2-14 GJB 150.5 Can the Two Tests Be Combined? Some users consider using a three-zone thermal shock chamber interchangeably with a rapid temperature change chamber if the latter achieves a rate of ≥25°C/min. For example, if the thermal shock range is -40°C to 85°C with a 5-minute recovery time and 30-minute dwell time, a rapid temperature change chamber with ≥25°C/min may suffice, as their working principles are similar. However, a basket-type thermal shock chamber (with instantaneous rates exceeding 25°C/min) should not be replaced by a rapid temperature change chamber, as it imposes harsher conditions and may lead to different failure modes.
