A Multi-stress Combination Reliability Test Method

Abstract

The present invention provides a multi-stress combination reliability test method, which includes the following steps: S1, pre-treating the test sample; S2, performing initial detection on the pre-treated test sample; S3, performing test preparation after completing the initial detection; S4, performing the test after completing the test preparation; S5, performing intermediate detection during the test, if the set conditions are met during the intermediate detection process, then performing steps S6 and S7 in sequence, if the set conditions are not met during the intermediate detection process, then directly performing step S7; S6, continuing the test and performing the final detection; S7, performing failure analysis. The present invention can penetrate the inside of the sample through a high temperature and high humidity humid environment, check the ability of the sample's external and internal resistance to high temperature, high humidity, and high salt spray environments, and evaluate or identify the environmental adaptability and reliability of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to a multi-stress combination reliability test method. Background Art

[0002] When electrical equipment is used in tropical island environments, it generally has a higher defect rate than when it is used in inland environments. The reason for this difference is closely related to the use environment of electrical equipment, especially the high temperature, high humidity and high salt fog environment in tropical island areas, which not only affects metal parts, but also electronic devices in electrical equipment, and easily causes problems such as reduced insulation performance, low impedance, leakage, open circuit or short circuit. For example: the resistance film layer (Ni, Cr, etc.) of precision resistors undergoes electrolytic oxidation under the influence of long-term environmental moisture, resulting in higher resistance or even open circuit and complete failure; the film of film capacitors undergoes electrolytic corrosion after being corroded by moisture, resulting in a serious decrease in capacity; ceramic capacitors undergo electromigration under high temperature and high humidity and short circuit; high-density pin devices such as chips have leakage between pins under the influence of high humidity and high salt fog, parameter degradation, logical disorder, poor function, etc.; the power module cannot start normally due to moisture leakage; PCB is damp and insulation decreases and sparks. This kind of failure caused by environmental factors is usually unpredictable in time, sometimes short and sometimes long. It is difficult to screen it out through testing or aging methods in production. Therefore, a multi-stress combination reliability test method is proposed to solve the above problem. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a multi-stress combination reliability test method to at least solve the above problems.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A multi-stress combination reliability test method, the method comprising the following steps:

[0006] S1. Pre-treat the test samples;

[0007] S2. Performing initial testing on the pre-treated test samples;

[0008] S3. Conduct test preparation after completing the initial test;

[0009] S4. Conduct the test after completing the test preparation work;

[0010] S5, perform an intermediate test during the test process. If the set conditions are met during the intermediate test process, proceed to steps S6 and S7 in sequence. If the set conditions are not met during the intermediate test process, proceed directly to step S7;

[0011] S6. Continue the test and conduct final inspection;

[0012] S7. Perform failure analysis.

[0013] Furthermore, in step S1, the pretreatment of the test sample is specifically as follows:

[0014] Place the test sample under normal atmospheric conditions for 24 hours, and remove the packaging materials and films on the surface of the test sample to keep it clean.

[0015] Furthermore, in step S2, the pre-treated test sample is subjected to initial testing as follows:

[0016] The pre-treated test samples were subjected to appearance inspection and electrical performance tests.

[0017] Furthermore, in step S3, after the initial test is completed, the test preparation work is specifically as follows:

[0018] The test samples that have undergone initial inspection shall be hung vertically or placed in the rack of the test box in normal use state; the spacing between the test samples should allow the salt spray to settle freely on all the samples; the salt solution on the surface of the sample shall not drip onto other samples; the samples will not touch each other and maintain electrical insulation between each other; the samples and the brackets shall maintain electrical insulation; the condensed water on the wall and top of the test box shall not drip onto the samples; and the operating parameters of the test box shall be set as follows: temperature: +70℃; humidity: 95%RH; nozzle pressure: 78.5~137.3kPa; salt spray deposition rate = 0.01% at a horizontal collection area of ​​80cm 2 The collector should collect an average of 1-2 ml of solution per hour; spray mode = continuous spray; test time and inspection time nodes 24, 48, 72, 96, 168, 240, 480, 720, 1000, 2000 hours.

[0019] Further, in step S4, after completing the test preparation work, the test is specifically performed as follows:

[0020] According to the normal power requirements of electrical equipment, provide the required mains voltage to the test sample and simulate the current during operation; set the timer switch interval to: 12 hours on, 12 hours off, and the salt spray chamber to work 24 hours; open the test chamber and conduct the test according to the set test conditions.

[0021] Further, in step S5, an intermediate test is performed during the test. If the set conditions are met during the intermediate test, steps S6 and S7 are performed in sequence. If the set conditions are not met during the intermediate test, step S7 is directly performed. Specifically, the following steps are performed:

[0022] During the test, each time the specified time point is reached, the test is interrupted and the sample is placed under the standard atmospheric conditions of the test for 2 hours before undergoing appearance inspection and electrical performance testing. If sample failure occurs during the intermediate inspection, steps S6 and S7 are performed in sequence; if sample failure does not occur during the intermediate inspection, step S7 is performed directly.

[0023] Further, in step S6, the test is continued and the final detection is performed as follows:

[0024] When the same test sample fails five times in succession, the test is terminated and the final test is carried out; when the total test time is 360 hours, the test is terminated and the final test is carried out.

[0025] Furthermore, in step S7, the failure analysis is performed as follows:

[0026] If any samples fail during the test, the failed samples will be analyzed after the final inspection, and the analysis process and results will be compiled into an analysis report.

[0027] Furthermore, in step S1, the test samples may include: smart energy meters, smart terminals and smart circuit breakers used in high temperature, high humidity and high salt fog environments.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention proposes a multi-stress combination reliability test method, which can simulate the high temperature, high humidity and high salt fog operating environment of electrical equipment in tropical island areas.

[0030] 2. The present invention proposes a multi-stress combination reliability test method, which can penetrate into the interior of the sample through a high temperature and high humidity humid environment, check the ability of the external and internal samples to resist high temperature, high humidity and high salt spray environments, and evaluate or identify the environmental adaptability and reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a schematic diagram of the overall process of a multi-stress combination reliability test method proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The enumerated embodiments are only used to explain the present invention and are not used to limit the scope of the present invention.

[0034] Reference Figure 1 The present invention provides a multi-stress combination reliability test method, the method comprising the following steps:

[0035] S1. Pre-treat the test samples;

[0036] S2. Performing initial testing on the pre-treated test samples;

[0037] S3. Conduct test preparation after completing the initial test;

[0038] S4. Conduct the test after completing the test preparation work;

[0039] S5, perform an intermediate test during the test process. If the set conditions are met during the intermediate test process, proceed to steps S6 and S7 in sequence. If the set conditions are not met during the intermediate test process, proceed directly to step S7;

[0040] S6. Continue the test and conduct final inspection;

[0041] S7. Perform failure analysis.

[0042] Exemplarily, this method is a combined test to simulate the impact of tropical island environment on electrical equipment. The purpose of the test is to superimpose neutral salt spray + high temperature + high humidity when the electrical equipment is powered on, to simulate the high temperature, high humidity and high salt spray operating environment of the electrical equipment in tropical island areas. The interior of the sample is penetrated by a high temperature and high humidity tidal environment to check the external and internal resistance to high temperature, high humidity and high salt spray environments, and to evaluate or identify the environmental adaptability and reliability of the product. Such as: the impact on protective coatings or platings in a salt spray environment; the intrusion and impact of moisture on internal circuits; the corrosion of exposed metals by electrochemical reactions with salt solutions when the power is on; whether the internal circuits will have functional failures due to moisture and salt spray when the power is on.

[0043] Determination of test parameters: 1. The test temperature is determined based on the following factors: 1) Ambient temperature. The highest temperature of the sample in the installation area is taken as the first reference temperature. 2) The maximum working temperature of the test sample. According to the sample execution standard, the specified maximum temperature of the test sample is taken as the second reference temperature. 3) The heating capacity of the test chamber is taken as the third reference temperature. Among them, the first reference temperature and the second reference temperature have the greatest influence on the final temperature.

[0044] Determination of test humidity: For the combined stress test of high temperature, high humidity and high salt spray, the general test humidity is 95%-100%.

[0045] The basis for determining the concentration of salt spray is: refer to GB / T 10125-2021, use 5% sodium chloride saline solution, and adjust the pH value of the solution to the neutral range (6-7) as the spray solution. The salt spray concentration measurement method is in accordance with GB / T 10593.2. The salt spray deposition measurement method is in accordance with GB / T 10593.2.

[0046] In step S1, the pretreatment of the test sample is specifically as follows:

[0047] Place the test sample under normal atmospheric conditions for 24 hours, and remove the packaging materials and films on the surface of the test sample to keep it clean.

[0048] In step S2, the pre-treated test sample is initially tested as follows:

[0049] The pre-treated test samples were subjected to appearance inspection and electrical performance tests.

[0050] Exemplarily, the initial inspection mainly includes appearance inspection and electrical performance test. For example, if the sample to be tested is a smart energy meter, it is necessary to carefully check the initial appearance of the smart energy meter and take photos to record whether there are scratches on its appearance, whether the screws are rusted, whether the labels are detached, whether the screen display is normal, etc. The electrical performance test of the smart energy meter includes but is not limited to: basic error, whether the communication function is normal, the power consumption of the whole machine, whether the cover opening event record is normal, etc.

[0051] In step S3, after the initial test is completed, the test preparation work is specifically as follows:

[0052] The test samples that have undergone initial inspection shall be hung vertically or placed in the rack of the test box in normal use state; the spacing between the test samples should allow the salt spray to settle freely on all the samples; the salt solution on the surface of the sample shall not drip onto other samples; the samples will not touch each other and maintain electrical insulation between each other; the samples and the brackets shall maintain electrical insulation; the condensed water on the wall and top of the test box shall not drip onto the samples; and the operating parameters of the test box shall be set as follows: temperature: +70℃; humidity: 95%RH; nozzle pressure: 78.5~137.3kPa; salt spray deposition rate = 0.01% at a horizontal collection area of ​​80cm 2 The collector should collect an average of 1-2 ml of solution per hour; spray mode = continuous spray; test time and inspection time nodes 24, 48, 72, 96, 168, 240, 480, 720, 1000, 2000 hours.

[0053] In step S4, after completing the test preparation work, the test is carried out as follows:

[0054] According to the normal power requirements of electrical equipment, provide the required mains voltage to the test sample and simulate the current during operation; set the timer switch interval to: 12 hours on, 12 hours off, and the salt spray chamber to work 24 hours; open the test chamber and conduct the test according to the set test conditions.

[0055] In step S5, an intermediate test is performed during the test. If the set conditions are met during the intermediate test, steps S6 and S7 are performed in sequence. If the set conditions are not met during the intermediate test, step S7 is directly performed. Specifically, the following steps are performed:

[0056] During the test, each time the specified time point is reached, the test is interrupted and the sample is placed under the standard atmospheric conditions of the test for 2 hours before undergoing appearance inspection and electrical performance testing. If sample failure occurs during the intermediate inspection, steps S6 and S7 are performed in sequence; if sample failure does not occur during the intermediate inspection, step S7 is performed directly.

[0057] In step S6, the test is continued and the final detection is performed as follows:

[0058] When the same test sample fails five times in succession, the test is terminated and the final test is carried out; when the total test time is 360 hours, the test is terminated and the final test is carried out.

[0059] In step S7, the failure analysis is specifically performed as follows:

[0060] If any samples fail during the test, the failed samples will be analyzed after the final inspection, and the analysis process and results will be compiled into an analysis report.

[0061] Exemplarily, failure analysis work is generally divided into two stages: product analysis stage and device analysis stage.

[0062] Product analysis phase:

[0063] According to the failure information of the sample and related materials (such as product specifications, circuit diagrams, schematics, PCB layout diagrams, device BOM tables, etc.), first determine the possible causes of the failure phenomenon, and then conduct analysis to prove it. If the analysis result is located as a device failure, a cross test should be carried out (that is, install the suspected device on a good board to observe whether the failure follows the device; or install the good device on the failed board to observe whether the board resumes normal operation), and then arrange the second stage of device analysis.

[0064] Device analysis phase:

[0065] When the failure of the sample is related to the device, it is necessary to analyze the cause of the failure of the device. Based on the analysis capabilities, the following three methods can be selected for analysis: 1. Analysis by the device manufacturer; 2. Analysis by the testing or analysis agency.

[0066] In order to take into account both accuracy and objectivity of the analysis, when there is only one failed device, select an optional testing or analysis agency for analysis; when there are two or more failed devices, one failed device can be sent to the optional device manufacturer for analysis first. If the analysis result is not acceptable, the other failed device can be sent to the optional testing or analysis agency for analysis.

[0067] The failure analysis of a device first requires understanding the failure information of the device, followed by appearance inspection and electrical performance testing. The failure mode is determined by the results of the electrical performance test. Then, a hypothesis is made about the failure mechanism based on the failure mode, and analysis is conducted to find the failure point. The failure mechanism is determined by the failure morphology of the failure point, the possible causes and directions of device failure are determined, and the direct factors leading to the failure are investigated.

[0068] In step S1, the test samples may include: smart energy meters, smart terminals and smart circuit breakers used in high temperature, high humidity and high salt fog environments.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-combination reliability test method, characterized in that: The method comprises the following steps: S1. Pre-treat the test samples, specifically: Place the test sample in normal atmospheric conditions for 24 hours, and remove the packaging materials and films on the surface of the test sample to keep it clean; S2. Perform initial testing on the pre-treated test samples, specifically: Conduct appearance inspection and electrical performance test on the pre-treated test samples; S3. After completing the initial test, conduct test preparation work, specifically: The test samples that have undergone initial inspection shall be hung vertically or placed in the rack of the test box in normal use state; the spacing between the test samples should allow the salt spray to settle freely on all the samples; the salt solution on the surface of the sample shall not drip onto other samples; the samples will not touch each other and maintain electrical insulation between each other; the samples and the brackets shall maintain electrical insulation; the condensed water on the wall and top of the test box shall not drip onto the samples; and the operating parameters of the test box shall be set as follows: temperature: +70℃; humidity: 95%RH; nozzle pressure: 78.5~137.3kPa; salt spray deposition rate = 0.01% at a horizontal collection area of ​​80cm 2 The collector should collect 1-2 ml of solution per hour on average; spray mode = continuous spray; test time and inspection time nodes 24, 48, 72, 96, 168, 240, 480, 720, 1000, 2000 hours; S4. Conduct the test after completing the test preparation work, specifically: According to the normal power requirements of electrical equipment, provide the required mains voltage to the test sample and simulate the current during operation; set the timer switch interval to: 12 hours on, 12 hours off, and the salt spray chamber to work 24 hours; open the test chamber and conduct the test according to the set test conditions; S5, perform an intermediate test during the test process. If the set conditions are met during the intermediate test process, proceed to steps S6 and S7 in sequence. If the set conditions are not met during the intermediate test process, proceed directly to step S7; S6. Continue the test and conduct final inspection; S7. Perform failure analysis.

2. A multi-combination reliability test method according to claim 1, characterized in that: In step S5, an intermediate test is performed during the test. If the set conditions are met during the intermediate test, steps S6 and S7 are performed in sequence. If the set conditions are not met during the intermediate test, step S7 is directly performed. Specifically, the following steps are performed: During the test, each time the specified time point is reached, the test is interrupted and the sample is placed under the standard atmospheric conditions of the test for 2 hours before undergoing appearance inspection and electrical performance testing. If sample failure occurs during the intermediate inspection, steps S6 and S7 are performed in sequence; if sample failure does not occur during the intermediate inspection, step S7 is performed directly.

3. A multi-combination reliability test method according to claim 2, characterized in that: In step S6, the test is continued and the final detection is performed as follows: When the same test sample fails five times in succession, the test is terminated and the final test is carried out; when the total test time is 360 hours, the test is terminated and the final test is carried out.

4. A multi-combination reliability test method according to claim 3, characterized in that: In step S7, the failure analysis is specifically performed as follows: If any samples fail during the test, the failed samples will be analyzed after the final inspection, and the analysis process and results will be compiled into an analysis report.

5. A multi-combination reliability test method according to claim 1, characterized in that: In step S1, the test samples may include: smart energy meters, smart terminals and smart circuit breakers used in high temperature, high humidity and high salt fog environments.

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