Performance test of 7 common PCBA circuit boards

PCB circuit board performance test is a necessary test to ensure the stability of product performance after the completion of PCBA processing. According to the actual environment and purpose of the product, it is generally divided into pressure test, insulation test, salt spray test, impedance test, vibration test, high temperature and humidity test, welding strength thrust test, etc. The following is a detailed introduction to the performance test of these 7 PCBA circuit boards.

1. Withstand pressure test

The purpose of the voltage test is to test the voltage resistance of the circuit board, the equipment needed is "voltage tester".

Test method: Connect the circuit board to the tester, increase the voltage to 500V DS (direct current) at a speed no higher than 100V/S, and keep it for more than 30 seconds. If there is no circuit fault, the test is passed.

2. Leakage current test

The purpose of leakage current test is to check whether the leakage current of the circuit board is within the requirements, and the equipment needed is "leakage current tester".

Test method: Simulate the leakage current between the product accessible part and the power supply pole under the normal working condition of the PCBA circuit board and the normal temperature of the circuit board. If the current is less than the design standard, the test is passed.

3. Salt spray test

The purpose of salt spray test is to check the corrosion resistance of circuit boards, and the equipment needed is "salt water spray testing machine".

Test method: First we want to configure salt solution, configuration method is: with chemical pure sodium chloride and resistivity of not less than 5000 ohm CM distilled water or deionized water made, with 5% sodium chloride and 95% water, after full mixing, made sodium chloride content of 5±1% salt solution. After the salt solution is configured, spray continuously for 48 hours in a test place with a temperature of 35℃, and the average amount of spray per hour should reach 80CM square /10CM. After 48 hours, if the functions of the product are normal and the appearance and structure are normal, the test is passed.

4. Impedance test

The purpose of impedance test is to check whether the printed circuit board can operate normally. The equipment required is the "ohmmeter".

Test method: Connecting the circuit board's transmission line to the battery, if we measure the impedance in less time than the transmission line reflects, we get a "surge" impedance or characteristic impedance. But if we wait long enough until the energy is reflected back and received, we measure a change in the impedance. In general, the impedance bounces up and down to a stable limit. If the limit value is within the specified range, the test is passed.

5. Vibration test

The purpose of vibration test is to test whether the circuit board can pass the random vibration test of different levels. The equipment needed is "vibration meter".

Test method: The circuit board or packaged circuit board was fixed on the test bench, the frequency was set at 20Hz, the axial direction was X, Y and Z, and the duration was one hour in each direction, for a total of three hours. After the test, the function of the circuit board was normal, its appearance and structure were normal, and no abnormalities such as component loosening or cracking were found, indicating that the test passed.

6. High temperature and humidity test

The purpose of high temperature and high humidity test is to check the applicability of the circuit board under the harsh conditions of high temperature and high humidity, and the equipment needed is "constant temperature and humidity test chamber".

Test method: PCBA circuit board in times rated voltage conduction, rated load working state, with the working attitude into the test box, to simulate the actual working temperature and humidity, if you do not know the actual working temperature and humidity, can set the temperature of 70±2℃, humidity between 90-95%, for 8 hours, if the basic function of PCBA circuit board is normal, If the appearance and structure are normal, the test passes.

7. Welding strength thrust test

The purpose of the thrust test of welding strength is to test whether the welding strength of components meets the requirements. The equipment needed is "thrust meter".

Test method: The welded PCBA circuit board is placed on the thrust meter. Components with different specifications have different passing requirements. Generally, other components at the edge of the target component will be eliminated, and then the instrument will be zeroed to carry out thrust test at an Angle ≤30 degrees, to check whether the components are unwelded, and to record the value of the components' unwelding.