PCB News - What are the basic knowledge and methods of PCB board inspection?

What are the basic knowledge and methods of PCB board inspection?

The reason why PCBs we come into contact with in our lives can be used more and more widely, because its unique advantages such as high reliability, high density, designability, manufacturability, etc. are closely related. The demand for PCBs has shown rapid growth for many years in terms of output and performance indicators. Correspondingly, higher requirements have been put forward for PCB quality testing. Traditional testing methods can no longer meet the requirements of the PCB industry for quality control. As an important part of modern electronic equipment, PCB boards are small in size and high in mounting density, which requires further improvement in the integration of PCB boards. The quality of PCB directly affects the quality of the entire electronic product, so PCB testing equipment is particularly important and critical. Various PCB tests are an inspection method to discover problems in time, and it is also a necessary means to prevent more defective products and reduce losses.

When inspecting PCB boards, we should pay attention to the following points:

1. Do not cause a short circuit between the pins when testing the PCB board;

2. Pay attention to the insulation performance of the soldering iron when testing the PCB board;

3. The internal resistance of the PCB board test instrument should be large;

4. Pay attention to the heat dissipation of the power integrated circuit when detecting the PCB board;

5. The lead wire of the PCB board should be reasonable

6. Inspect PCB board to ensure welding quality

7. Do not easily determine the damage of the integrated circuit when testing the PCB board

8. Before testing the PCB board, understand the working principle of integrated circuits and related circuits

What should be done before PCB testing? First understand the working environment of the equipment, mainly consider the possible impact of external electrical parameters on the equipment; ask what happens when the circuit board fails, and analyze the cause of the failure; carefully check the components on the circuit board to find out what is right Which components do the circuit board play a key role? Take anti-electromagnetic, static and other interference measures.

So, what are the commonly used inspection methods in the PCB production process? In addition to the high cost of manual visual inspection, certain errors are generated due to long-term visual inspection, coupled with the reduction of the wire spacing and component volume on the PCB, the requirements for manual visual inspection are also increasing. Obviously, with the continuous increase in PCB production Increase, this method is becoming more and more unsuitable; there is also a PCB board function test, this functional system test is to use special test equipment in the middle and end of the production line to conduct a comprehensive test on the functional modules of the circuit board., To confirm the quality of the circuit board. It requires special equipment and a specially designed test process, and it is complicated to write functional test programs, so it is not suitable for most circuit board production lines. But nowadays, there is a kind of size detection that is relatively widely used. It uses a two-dimensional image measuring instrument. Measure the hole position, length and width, position and other dimensions. Because PCB is a small, thin and soft type of product, contact measurement is prone to deformation and inaccurate measurement. The second-dimensional image measuring instrument has become the choice of high-precision size measuring instruments. After being programmed, the image measuring instrument of Sirui Measurement can realize fully automatic measurement, which not only has high measurement accuracy, but also greatly shortens the measurement time and improves the measurement efficiency.

It is precisely because PCB has a wide range of applications in today's society, so there may be questions about the PCB inspection process. I will tell you some practical methods of operability that I have summarized after many years of testing. This method is provided to everyone, hoping to provide a useful reference for everyone's circuit board inspection work in practice. The PCB factory has always adhered to the exquisite technical force, sophisticated production equipment, perfect testing methods, product quality higher than the industry standard, and warm and thoughtful service, which has won praise and welcome from global merchants and users.