MIL-STD 202 Thermal Shock Testing
MIL-202 temperature shock testing helps determine the resistance of material to extremes of high and low temperatures. This test also evaluates the ability of material to withstand the shock of alternate exposures to these extremes. This might be experienced when equipment or parts are transferred to and from heated shelters in arctic areas. These conditions may also be encountered in equipment operated non-continuously in low-temperature areas or during transportation.
It is better for the specimen to reach thermal stability during the exposure specified. However, to save time, parts may be tested at the minimum exposure durations, which will approach, but not ensure thermal stability. Permanent changes in operation and physical damage caused variations in dimensions and other physical properties, may result.
Effects of MIL-STD 202 thermal shock include cracking and delamination of finishes. Cracking and crazing of embedding and encapsulating compounds may be an effect. Opening of thermal seals and case seams may occur. Materials may experience leakage of filling materials, rupturing, or cracking of hermetic seals and vacuum glass to metal seals. Changes in electrical characteristics may result from mechanical displacement or rupture of conductors or of insulating materials.
Keystone Compliance is a temperature shock testing lab, with significant MIL-202 thermal shock experience. Our experienced test engineers understand the requirements of MIL-STD 202 temperature shock compliance. The following information is extremely technical as it provides a summary of the MIL-STD-202 temperature shock testing requirements.
What Procedure Provides the Best Thermal Shock Testing?
All testing must be done in a thermal shock laboratory. Procedures may include environmental testing chambers and/or liquid baths. Materials are placed in the chambers so that there is no obstruction to the flow of air across and around it. When special mounting is required, it will be specified.
The first five cycles are run continuously, after this the test may be interrupted after the completion of any full cycle. Allow the specimens to return to room ambient temperature before resuming testing. One cycle consists of steps 1 through 4 of the applicable test condition.
Specimens should not be subjected to forced circulating air while being transferred from one chamber to another. Total transfer time from low to high temperature chambers, or vica-versa, should not exceed 5 minutes. The transfer time is the time between withdrawal from low temperature, and introduction into high temperature or visa versa.
Specimens may be immersed in a suitable liquid approved by the qualifying activity. The bath should be at the temperature in step 1 of the specified test condition, for the time specified. Immediately after step 1, the device is transferred to a suitable liquid at the temperature specified in step 2.
These two steps, step 1 and 2, constitute one cycle of the applicable test condition. Repeat the required number of cycles without interruption as specified. Transfer time from low to high temperature and from high to low temperature should be less than 10 seconds.
Specified measurements shall be made prior to the first cycle and upon completion of the final cycle. However, failures are based on measurements made after the specimen has stabilized at room temperature following the final cycle.
What Physical and Chemical Effects Does Temperature Shock Have on Material?
Several physical and chemical problems may occur when materials are exposed to the environments of the thermal shock testing lab. The lubricants could evaporate and gases or fluids could leak from gasket-sealed enclosures. Hermeneutic seals may fail, and material may experience overheating due to reduced heat transfer.
The physical and chemical properties of low-density materials may experience a change. Sealed containers could deforme, rupture, or explode. Engines could experience erratic starting and operation problems. Any of these problems would indicate that material should not receive thermal shock certification.
What Temperature Shock Laboratory Provides the Best Temperature Shock Testing?
Keystone Compliance has been recognized as one of the best thermal shock labs in the country. Our test engineers understand the requirements of thermal shock compliance testing. We are equipped to provide temperature shock certifications for commercial, military, and aerospace products. Contact us to learn why Keystone Compliance is the best temperature shock lab to meet your compliance testing needs.
Looking for other MIL-STD-202 compliance tests? Click on a link below to learn more about the other test methods.
- MIL-STD-202 Test Method 101 Salt Atmosphere (Corrosion)
- MIL-STD-202 Test Method 103 Humidity (solid state)
- MIL-STD-202 Test Method 104 Immersion
- MIL-STD-202 Test Method 105 Barometric Pressure
- MIL-STD-202 Test Method 106 Moisture Resistance
- MIL-STD-202 Test Method 107 Thermal Shock
- MIL-STD-202 Test Method 108 Life (at elevated ambient temperature)
- MIL-STD-202 Test Method 109 Explosion
- MIL-STD-202 Test Method 110 Sand and Dust
- MIL-STD-202 Test Method 111 Flammability (external flame)
- MIL-STD-202 Test Method 112 Seal
- MIL-STD-202 Test Method 201 Vibration
- MIL-STD-202 Test Method 203 Random Drop
- MIL-STD-202 Test Method 204 Vibration, High Frequency
- MIL-STD-202 Test Method 206 Life (rotational)
- MIL-STD-202 Test Method 207 High-Impact Shock
- MIL-STD-202 Test Method 208 Solderability
- MIL-STD-202 Test Method 209 Radiographic Inspection
- MIL-STD-202 Test Method 210 Resistance to Soldering Heat
- MIL-STD-202 Test Method 211 Terminal Strength
- MIL-STD-202 Test Method 212 Acceleration
- MIL-STD-202 Test Method 213 Shock (specified pulse)
- MIL-STD-202 Test Method 214 Random Vibration
- MIL-STD-202 Test Method 215 Resistance to Solvents
- MIL-STD-202 Test Method 216 Resistance to Solder Wave Heat
- MIL-STD-202 Test Method 217 Particle Impact Noise Detection
- MIL-STD-202 Test Method 301 Dielectric Withstanding Voltage
- MIL-STD-202 Test Method 302 Insulation Resistance
- MIL-STD-202 Test Method 303 DC Resistance
- MIL-STD-202 Test Method 304 Resistance-Temperature Characteristic
- MIL-STD-202 Test Method 305 Capacitance
- MIL-STD-202 Test Method 306 Quality Factor
- MIL-STD-202 Test Method 307 Contact Resistance
- MIL-STD-202 Test Method 308 Current-Noise Test for Fixed Resistors
- MIL-STD-202 Test Method 309 Voltage Coefficient of Resistance Determination Procedure
- MIL-STD-202 Test Method 310 Contact-Chatter Monitoring
- MIL-STD-202 Test Method 311 Life, Low Level Switching
- MIL-STD-202 Test Method 312 Intermediate Current Switching