MIL-STD 883 Thermal Shock Testing
The purpose of the MIL-883 thermal shock test is to determine the resistance of material to sudden exposure to extreme changes in temperature. All testing should be performed in a temperature shock laboratory. Below are some definitions of temperature shock testing terms mentioned in MIL-STD 883 thermal shock. The following information is extremely technical in nature, it provides a summary of MIL-STD-883 temperature shock testing.
MIL-STD-883 defines a cycle as consisting of starting at ambient room temperature, proceeding to step 1, then to step 2. Alternately it may proceed to step 2, then to step 1, and back to ambient room temperature without interruption.
A load is the devices being tested and the fixture holding these devices. A maximum load is the minimum mass of devices and fixtures that can be placed in the bath while maintaining the temperatures and times specified in MIL-STD 883 temperature shock. A specimen is the device or individual piece being tested in the thermal shock laboratory.
Transfer time is the elapsed time measured from the removal of one load from one bath until it is put into another bath. Dwell time is defined as the total time the load is immersed in the bath. The worst case load temperature is the body temperature of a specific device located at the center of the load.
The monitoring sensor is located and calibrated to indicate the same temperature as at the worst case indicator specimen location. In temperature shock testing the worst case indicator specimen location is identified during the periodic characterization of the worst case load temperature.
What is the Appropriate Apparatus of a Thermal Shock Testing Lab?
The baths used for temperature shock compliance testing should be capable of providing and controlling the specified temperatures in the working zone(s) when loaded with a maximum load. The thermal capacity and liquid circulation must enable the working zone and loads to meet the conditions and timing specified in MIL-STD 883 thermal shock. Indicators or recorders read the monitoring sensors in the temperature shock testing lab to continuously track worst case load temperature.
The worst case load temperature under maximum load conditions and configuration is verified as needed to validate bath performance. Perfluorocarbons that meet the physical property requirements of the table below are used for test conditions B and C.
Keystone Compliance is one of the best temperature shock labs, with significant MIL-STD 883 thermal shock testing experience. Our thermal shock testing lab has all the best test equipment for all your thermal shock certification needs. Our test engineers understand the requirements of MIL-STD-883 thermal shock compliance testing.
What is the Correct Procedure for Temperature Shock Compliance Testing?
For the best temperature shock testing, specimens are placed in the bath in a way that the flow of liquid across and around them is mostly unobstructed. Test condition B, or an otherwise specified condition of the table below, is applied for 15 cycles. Completion of the total number of cycles may be interrupted to load or unload device lots or as the result of power or equipment failure. If the number of interruptions exceeds 10% of the total number of cycles specified, the test must be restarted.
For the best thermal shock testing, the total transfer time from hot to cold or from cold to hot should not exceed 10 seconds. The load may be transferred when the worst case load temperature is within the limits specified in the table below. The dwell time should not be less than 2 minutes and the load should reach the specified temperature within 5 minutes.
This table contains information on thermal shock temperature tolerances and suggested fluids.
|Step 1||Temperature tolerance, °C|
|Step 2||Temperature tolerance, °C|
What is the Best Way to Examine Material After Testing?
After performing thermal shock testing, an external visual examination of the marking is performed. This is done either without magnification or with magnification no greater than 3X. A visual examination of the case, leads, or seals is performed at a magnification between 10X and 20X. However, the magnification for examination is 1.5X minimum when this method is used for 100 percent screening.
This examination and any additional specified measurements and examination is made after completion of the final cycle. Or it is made upon completion of the group, sequence, or subgroup of tests which include this MIL-883 temperature shock test.
After testing, failure of any specified end-point measurements or examinations constitutes failure. Failure is also evidenced by defects or damage to the case, leads, or seals, or illegible markings. Damage to marking caused by fixturing or handling during tests is not cause for device rejection.
Where is the Best Thermal Shock Lab for My Compliance Testing Needs?
Keystone Compliance has been recognized as one of the best temperature shock labs in the country. Our experts are able to provide temperature shock certifications for commercial, military, and aerospace products. Contact us to learn why so many manufacturers rely on Keystone Compliance to meet their compliance testing needs.
MIL-STD-883 testing contains several test methods. For more information about these test methods, please click on one of the links below
- Method 1001 Barometric pressure, reduced (altitude operation)
- Method 1002 Immersion
- Method 1004 Moisture resistance
- Method 1005 Steady-state life
- Method 1006 Intermittent life
- Method 1007 Agree life
- Method 1008 Stabilization bake
- Method 1009 Salt atmosphere
- Method 1010 Temperature cycling
- Method 1011 Thermal shock
- Method 1012 Thermal characteristics
- Method 1013 Dew point
- Method 2001 Constant acceleration
- Method 2002 Mechanical shock
- Method 2005 Vibration fatigue
- Method 2006 Vibration noise
- Method 2007 Vibration, variable frequency
- Method 2015 Resistance to solvents
- Method 2026 Random vibration