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MIL-STD 202 Accelerated Aging Testing

MIL-STD 202 accelerated aging testing helps determine the electrical and mechanical effects of exposure of a part to elevated ambient temperatures. This exposure occurs for a specific amount of time, while the part is operating. This test method is not intended for testing parts whose life is expressed in the number of operations.

Evidence of deterioration resulting from this test can at times be determined by visual examination. However, the effects may be more readily ascertained by measurements or tests prior to, during, or after exposure. These measurements may include surge current, total resistance, dielectric strength, insulation resistance, and capacitance.

Keystone Compliance is an accelerated aging testing lab, with significant MIL-STD-202 reliability experience. Our test engineers understand the requirements of MIL-202 accelerated aging compliance testing. The following is a summary of MIL-202 reliability certification requirements.

What is Apparatus is Best for Reliability Compliance Testing?

All testing should be done in an accelerated aging laboratory, equipped with a suitable test chamber. This chamber must be able to maintain the temperature and the tolerance that the parts will be subjected to. Chamber construction will minimize the influence of radiant heat on the parts being tested. Circulating liquid chambers, free-convection chambers, and circulating air chambers may be used providing the other requirements of the test are met.

Temperature measurements are made within a specified number of unobstructed inches from any part or group of like parts under test. The temperature measurement must also be made where the heat generated by the parts have the least effect on the recorded temperature.  When specified, this test is done in still air, which is air with no circulation other than that created by the heat of the part being operated.

The employment of baffling devices and the coating of their surfaces with a heat-absorbing finish are permitted. When a test is conducted on parts that do not have the still-air requirement, there is no direct impact of the forced-air supply upon the parts. Keystone Compliance is one of the best accelerated aging labs in the country.

What is the Procedure for the Best Accelerated Aging Testing?

Specimens must be mounted by their normal mounting means. When groups of specimens are subjected to testing simultaneously, the mounting distance between specimens is as specified for the individual groups. When the distance is not specified, it must be sufficient to minimize the temperature of one specimen affecting the temperature of another. Specimens of different materials, that may poorly affect one another and alter the results of this test, should not be tested simultaneously.

Specified measurements should be made prior to, during, or after exposure, as specified. Frequency of measurements, and the portion of the duty cycle in which they are made, while the item is being tested, are as specified. Specimens will be subjected to one of the following test temperatures with accompanying tolerances, as specified:

Temperature and tolerance 1/
°C°F

70 ±2

85 ±2

100 ±2

125 ±3

150 ±3

200 ±5

350 (± as specified)

500 (± as specified)

158 ±3.6

185 ±3.6

212 ±3.6

257 ±5.4

302 ±5.4

392 ±9

662 (± as specified)

932 (± as specified)

1/ For tests on resistors only, in a still-air environment, the maximum temperature tolerance are ±5°C (±9°F).

Specimens must be subjected to one of the following test conditions for the specified amount of time.

Test ConditionLength of Test in Hours
A96
B250
C500
D1,000
E (Deleted from this method)1,500
F2,000
G3,000
H5,000
I10,000
J30,000
K50,000

What Reliability Testing Lab Provides the Best Reliability Testing?

Keystone Compliance has been recognized as one of the best reliability labs in the country. Our test engineers and reliability laboratory are equipped to provide accelerated aging certifications for commercial, military, and aerospace products. Contact us to learn why so many manufacturers rely on Keystone Compliance for all their compliance testing needs.

Looking for other MIL-STD-202 compliance tests? Click on a link below to learn more about the other test methods.