What Is Thermal Shock?
The thermal shock test is one in which a sudden temperature change is applied by transferring the sample between hot and cold environments in a very short time. It is defined as method Na in IEC 60068-2-14.
Purpose of Thermal Shock
The purpose is to reveal, in accelerated form, the cracking and separation caused by sudden temperature change in joints of materials with different expansion coefficients.
Which Products Is Thermal Shock Applied To?
- Electronic boards and components
- Glass and ceramic parts
- Coated metal surfaces
- Battery cells
- Automotive sensors
In Which Sectors Is Thermal Shock Used?
Standards Related to Thermal Shock
- IEC 60068-2-14temperature change test test
- MIL-STD-810 Method 503
- JEDEC JESD22-A106
- ISO 16750-4Environmental conditions in vehicle electrical/electronic equipment test
Thermal Shock Conditions
- temperatures
- Upper and lower temperature defined in the specification
- Transfer time
- The maximum period defined in the standard; typically under 10 seconds (two-bay cabinet)
- Holding time
- Time to equilibrate the sample in each compartment
- Number of cycles
- Defined in the specification
Equipment for Thermal Shock
- Two-chamber thermal shock unit (with transfer basket)
- Multi-channel temperature recording
- Function or resistance monitoring
- Data logging system
Sample Requirements for Thermal Shock
- The sample must fit within the transfer basket
- Function must be checked before the test
- Thermocouples must be connected at critical points
- The number of specimens is set out in the specification
Duration of Thermal Shock
Depends on the number of cycles and dwell time; typical programmes last days to weeks.
Thermal Shock Procedure
- 1The sample is placed in the basket and monitoring is set up.
- 2The chamber temperatures are brought to their target values.
- 3The sample is held in the hot chamber for the defined duration.
- 4It is transferred to the cold chamber within the defined transition time and held there.
- 5The cycle is repeated the defined number of times.
- 6A final function check and visual inspection are carried out.
Thermal Shock Acceptance Criteria
The acceptance criterion is defined in the specification: continuity of function, no cracking or coating delamination.
Evaluation of Results
Visual inspection and, if required, metallographic cross-section examination are performed. Solder and adhesive joints are checked for cracking.
Thermal Shock Report
- Standard and method applied
- Temperatures, transition and dwell times
- Number of cycles
- Functional status and inspection results
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Electronic component and automotive specifications
Environmental and Climatic Testing — What Does This Testing Field Cover?
The section below describes the field that the Thermal Shock test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Environmental testing shows whether a product withstands ambient factors such as temperature, humidity, pressure, solar radiation, dust, water and corrosive atmospheres. The aim is not to break the product but to bring forward, in ACCELERATED form, the conditions it will meet over its life.
Test profiles are derived from the product's real exposure, and that derivation is the actual engineering work of the field. A device operating in an enclosed office and one mounted on a pole are not tested with the same profile. The IEC 60068 series defines general methods, MIL-STD-810 military profiles, RTCA DO-160 aviation profiles and the ISO 16750 series location-based automotive profiles. A test applied without a profile selection produces both unnecessary cost and false confidence.
Temperature tests simulate three separate phenomena and all three produce different failure modes. Steady high/low temperature tests whether the material can operate at that temperature. Temperature CYCLING creates fatigue at joints between materials with different expansion coefficients — solder cracks appear here. Thermal SHOCK intensifies this effect through an abrupt transition.
There is a distinction in humidity testing too. Steady damp heat shows the diffusion of moisture into the material and its effect on insulation properties. Cyclic damp heat creates condensation: water droplets form on the cooling surface, and this is far more aggressive than dry humidity. Water ingress into enclosures, increased leakage current and corrosion usually appear in the cyclic test.
Dust and water protection is a separate body of work and is expressed by the IP code. The point to note here is that an IP test is not a DURABILITY test: it shows that protection is provided under defined and short-duration conditions, not resistance to long-term immersion or pressure washing.
The most common mistake in this family is translating a test result directly into a LIFE PREDICTION. Accelerated tests are designed for comparison and design verification; a reliable conversion between hours in a chamber and years in the field can only be established with a material-specific acceleration model calibrated against field data.
Functional monitoring determines the value of the test. Keeping a product in a temperature chamber and then switching it on does not show what happened DURING the test. In critical applications the product is operated throughout the test and its parameters are monitored; intermittent faults that appear and disappear can only be caught this way.
Method groups in this field
Temperature
Dry heat, cold, change of temperature and thermal shock; steady and cyclic profiles.
Humidity
Steady damp heat and cyclic damp heat; cycles with condensation are more aggressive.
Water and dust
IP protection tests: dripping, spraying, jets, immersion and dust tightness.
Radiation and ageing
Accelerated ageing by xenon arc and fluorescent UV, solar radiation simulation.
Pressure and altitude
Low pressure (altitude) and rapid pressure change tests.
Corrosive atmosphere
Salt spray, mixed flowing gas corrosion (simulating industrial atmospheres), mould and fungus tests.
Commonly confused in this field
- Test duration cannot be converted into field life; a conversion made without an acceleration model is misleading.
- Temperature cycling and steady temperature produce different failure modes; neither replaces the other.
- If the product is not operated during the test, intermittent faults remain invisible; functional monitoring determines the value of the test.
- IP protection is not evidence of durability; it shows protection under defined and short-duration conditions.
- A test applied without profile selection both increases cost and gives false confidence.
- The mounting and orientation arrangement affects the result; the report must document it.
Which decisions these results support
- Design verification and qualification
- Declaration of the protection class and operating temperature range
- Reproducing field failures in the laboratory and root cause analysis
- Supplier component approval
- Decisions on warranty period and storage conditions
Related Tests
Frequently Asked Questions About Thermal Shock
According to which standard is Thermal Shock made?
Thermal Shock is executed in scope IEC 60068-2-14, MIL-STD-810 Method 503, JEDEC JESD22-A106 and ISO 16750-4. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Thermal Shock apply to?
Mainly applied to Electronic boards and components, Glass and ceramic parts, Coated metal surfaces, Battery cells and Automotive sensors. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Thermal Shock done?
The determining parameters are: temperatures — Upper and lower temperature defined in the specification, Transfer time — The maximum period defined in the standard; typically under 10 seconds (two-bay cabinet) and Holding time — Time to equilibrate the sample in each compartment. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Thermal Shock?
The sample must fit within the transfer basket, Function must be checked before the test and Thermocouples must be connected at critical points. The number of samples is determined according to the product standard and the scope to be reported.
How long does Thermal Shock take?
Depends on the number of cycles and dwell time; typical programmes last days to weeks. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Thermal Shock result called "appropriate"?
The acceptance criterion is defined in the specification: continuity of function, no cracking or coating delamination.