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How to do Reliability test for Electronics

July 10,2023

Everyone should be familiar with electronic components, but what about the reliability of electronic components? The reliability of electronic components is an important factor affecting product reliability. The reliability test is to determine whether the products that have passed the reliability appraisal test and have been transferred to mass production meet the specified reliability requirements under specified conditions, and to verify whether the reliability of the product is consistent with the process, tooling, work process, and parts during mass production. Decrease due to changes in quality and other factors. Only through these, the product performance can be trusted, and the product quality is excellent.

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Reliability test is an important means to evaluate product reliability level. At present, various tests such as measurement, verification, evaluation, and analysis to improve product reliability are collectively referred to as reliability tests. Reliability testing is an important part of product reliability work. Reliability tests are generally carried out during product development and mass production. In the research and development stage, reliability tests are mainly used to evaluate design quality, material and process quality. In the mass production stage, the purpose of reliability testing is quality assurance or regular assessment management.

Due to the different stages, their purpose and content are not exactly the same.

The Purpose of Reliability Test

1) Determine the reliability characteristic value of electronic components through experiments. The test exposes problems and related data in the design, material and process stages, which are very useful to designers, producers and users.

2) Through the reliability appraisal test, it is possible to comprehensively assess whether the electronic components have reached the predetermined reliability index. This is a necessary step for the design and finalization of new electronic components.

3) Through various reliability tests, understand the failure law of the product under different working and environmental conditions, determine the failure mode, and obtain the failure mechanism, so as to take effective measures to improve product reliability.

Classification of Reliability Tests

There are many classification methods for reliability tests commonly used in electronic components.

Reliability tests can be divided into two categories according to their test locations and test methods: field tests (on-site measurement of working reliability) and simulation tests (tests that simulate actual working conditions). Most of the reliability tests carried out in the laboratory are simulation tests. The simulation test is divided into destructive test and non-destructive test according to its test nature.

Reliability test can be divided into

● reliability identification test,

● life test,

● durability test,

● screening test,

● reliability growth test, etc.

According to the purpose of the test. The reliability identification test is a test to determine whether the reliability characteristic value of the product reaches the required level; the life test is a test to evaluate and analyze the life characteristic value of the product; the durability test is to investigate the performance of the product and The influence relationship of the applied stress conditions and the test carried out within a certain period of time; the screening test is a test for selecting products with certain characteristics or eliminating early failure products; the reliability growth test is to take corrective measures, systematically and A test that permanently eliminates certain failure mechanisms and improves the reliability of components to meet or exceed predetermined reliability requirements.

Environmental Test

Environmental testing aims to understand the adaptability of products to environmental conditions, especially working in special environments or harsh environmental conditions. Environmental conditions play a role of "accelerating and aggravating" the potential failure factors inside the product, and it is a factor that leads to the formation of a certain failure mechanism. Environmental testing requires observing the environmental stress that the product can withstand in a short period of time. Environmental conditions mainly include:

1) Climatic conditions, including temperature, humidity, air pressure, hot flashes, salt spray, etc.;

2) Mechanical conditions, mainly vibration, shock, centrifugal, etc.;

3) Radiation conditions, mainly electric field, magnetic field, electromagnetic field, and radiation of other rays;

4) biological conditions, mainly mold;

5) Electrical conditions, mainly lightning strikes, corona discharge, etc.;

6) Man-made conditions, such as transportation, use, maintenance, etc.

Of course, as the environmental test of electronic products, not all the above-mentioned items are carried out, but the items similar to the working environment are selected, or the items that have the most significant impact on the reliability of electronic products are selected. Such as

● High and low temperature

● Temperature shock,

● Temperature cycle,

● hot flashes,

● vibration,

● shock,

● centrifugal,

● salt spray,

● Altitude pressure, etc.

They can be a single environmental test, or a combination of multiple environmental tests.

High and Low Temperature Test

Most electronic components have a working temperature range, beyond this range, they will fail or their performance will be reduced.

the civilian grade0~70℃
the industrial grade -40~85℃
the military grade -55~128℃

This is because it refers to a material whose conductivity is between that of a conductor and an insulator at room temperature, and changes in temperature have a great impact on the conductivity, limit voltage, limit current, and switching characteristics of semiconductors. Now a chip often contains millions or even tens of millions of transistors and other components, and the accumulation of every small deviation may cause a huge impact on the external characteristics of the semiconductor. If the temperature is too low, it will often cause the chip to fail to open its internal semiconductor switch under the rated operating voltage, resulting in its failure to work normally.

LIB benchtop temperature and humidity test chamber is of high quality and low cost and is suitable to do this kind of test for electronics.

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Temperature Shock Test

Purpose of the test: To assess the ability of the product to withstand drastic changes in temperature, that is, the ability to withstand a large rate of temperature change. The test can cause the failure of the product due to the deterioration of the mechanical structure defect. The purpose of the thermal shock test is basically the same as that of the temperature cycle test, but the conditions of the thermal shock test are much harsher than the temperature cycle test. The heat capacity is an important factor to ensure the test conditions.

Temperature shock test is a test method to test the performance stability of products under extreme temperature changes. The test simulates the extreme temperature conditions that the product may encounter in the real environment by placing the tested product in a high temperature and low temperature environment for cyclical changes, so as to evaluate the reliability and durability of the product under these conditions.

In the temperature shock test, the product under test will be placed in a high-temperature environment for a period of time, and then quickly moved to a low-temperature environment, and this process is repeated many times. This rapid temperature change can lead to thermal expansion and contraction of product materials, thereby causing changes in internal stress, and testing the durability and reliability of products under such changes.

Temperature shock test is widely used in electronic products, auto parts, aerospace equipment and other fields. This test method can help manufacturers evaluate the reliability and durability of products under extreme temperature changes, thereby improving product design and manufacturing processes, and improving product quality and performance.

Usually -55℃-125℃, 5-10 shocks

Salt Spray Corrosion Test

In fact, there are a wide range of electronic components that require salt spray corrosion tests, such as exposed metal casings: intermediate frequency transformers, shielding covers, PCB circuit boards, aluminum shell capacitor shells, metal crystal oscillator shells, some switches with contacts, radios Variable capacitors, potentiometers, etc.

Procedure:

1. Before the experiment, the test sample should be visually inspected, and the electrical and mechanical properties should be tested according to the regulations.

2. The dust and oil stains on the surface of the test sample should be thoroughly removed immediately before the test until no water droplets hang on the surface. The solvents used do not cause corrosion and do not form a protective film. Organic coatings should not be cleaned with organic solvents. Unless otherwise specified, the parts in contact with the sample holder and the cut surfaces and surfaces that do not need to be coated shall be protected by a layer of wax or other similar substances.

3. The test samples should be placed to avoid contact with each other, and the effect of salt spray should not be shielded from each other. The main surface of the plate test sample should form an angle of 15°~30° with the vertical direction.

4. If the test chamber has been out of use for more than 5 days before the experiment, it should be tested empty for 24 hours to ensure that the temperature and sedimentation rate meet the test requirements before starting the test. It can be sprayed when the temperature of the working space is stable at 35±2°C.

The test shall be carried out continuously, and the test time shall be selected by relevant standards.

Altitude/Low Pressure Test

Under the action of the earth's gravity, the air adheres to the surrounding earth to form the atmosphere, which extends from the ground to hundreds of kilometers above the sky. The gravitational force of the earth makes the air have a certain weight to form atmospheric pressure. The atmospheric pressure at a certain height is the weight of the entire air column per unit area perpendicular to the ground above this point. Atmospheric pressure is isotropic, that is, at a certain point, no matter which direction the atmospheric pressure is measured, it is the same. Atmospheric pressure mainly depends on the altitude. As the altitude increases, the atmospheric pressure gradually decreases and the atmosphere gradually becomes thinner. At a height close to 5.5km, the atmospheric pressure drops to about half of the standard atmospheric pressure at sea level; at 16km, the atmospheric pressure is 1/10 of the standard sea level; at 31km, the atmospheric pressure is 1 of the standard atmospheric pressure at sea level /100. The reduction of atmospheric pressure will inevitably have an impact on electrical and electronic products used in high altitude areas.

As the altitude increases, the air pressure decreases, which will also affect the performance of electronic components. Especially for equipment that uses air as the insulating medium, the impact of low air pressure on it is more significant. Under normal atmospheric conditions, air is an excellent insulating medium, and many electrical products use air as an insulating medium. When these products are used as mechanical equipment in high-altitude areas, partial discharges often occur near electrodes with strong electric field strength due to the reduction of atmospheric pressure. What's more serious is that air gap breakdown sometimes occurs, which means that the normal operation of the equipment is damaged.

① Pressure:

3 000m70kPa
18 000m6kPa
25 000m5 kPa

② Time:

Unless otherwise specified, the test time of the test sample under low pressure conditions can be selected from the following values:

5min30min1h2h4h16h

③ The rate: 3.35Kpa/min(from standard to 0.5Kpa≤30min)

④ Test equipment:

LIB Altitude test Chamber allows users to control the environmental test chamber temperature while subjecting the product under test to various levels of altitude. This combination of elements allows precise simulation of real-life conditions a product might encounter at various altitude levels.

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Summary

The test of electronics is an indispensable basic work, and the parameters of different components are different, which requires the laboratory to have strong testing capabilities, including equipment capabilities and technical personnel. With perfect equipment and rich project experience, LIB can provide customized reliability testing services for different electronics, including solutions, reliability tests, parameter measurement, data analysis and failure analysis one-stop services.If you are interested, contact us now.

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