What Is the Key Technology of PCB Defect Detection

PCB, that is, printed circuit board, is the carrier connecting various electronic components in electronic products. It is one of the important components of the electronic industry. In this article, I will share the common defect detection technology of PCB, hoping to be helpful to users.

The common defect detection technologies of PCB circuit board include automatic optical detection technology, machine vision detection technology, computer vision detection technology and so on.

1. Artificial visual subjective judgment method

The operator needs to determine the qualification rate of PCB with the help of electron microscope or magnifying glass according to the subjective experience and visual measurement of the operator. The budget cost of this technology is low, the required equipment is cheap and easy to operate, but the accuracy is low, the defect detection efficiency is low, and the data collection analysis is difficult.

2. Instrument online detection method

Operators can check the open circuit, short circuit and other faults of circuit board welding and the function detection of components through simulation test experiment and electrical performance test. They can also detect the electronic components with excessive density on PCB through boundary scanning technology, and collectively detect the welding points and connections of circuit board. It is a detection technology based on electrical signal as the medium. The advantages of this technology are high conversion rate, low cost and large detection coverage, but the operation is difficult and the operation time is long.

3. Function test method

Operators comprehensively test the functional modules of the circuit board on the production line with the help of special test equipment to confirm the good or bad state of the circuit board, but they can not provide in-depth data such as improved electronic components and pin diagnosis. They need to use different test equipment according to different needs, so it is difficult to write the program.

4. Visual inspection technology

Visual inspection technology has covered many fields such as electronics, computer, artificial intelligence and image processing. It has become the mainstream research method of PCB defect detection in today's society. It is mainly divided into:

1) Automatic optical inspection technology (AOI):

Integrated with image processing, automatic control and other computer technologies, PCB welding defects are detected and processed based on optical principle. Mainly scan the PCB through the camera and obtain the image of the PCB solder joint area. Automatically detect the PCB defects through the visual processing technology, extract the characteristic data of each solder joint, contact the database for comparison, determine the types of solder joint defects, identify them, and give the number of detection results.

2) Machine vision inspection technology (MVI):

Combined with CMOS, digital image sensor, DSP, FPGA and other technologies, the machine is used to replace the naked eye for a variety of PCB measurement and judgment. Because it uses a variety of machine technologies, it is very popular in the field of precision testing and is often used in industrial PCB testing. It has the advantages of fast speed, non-contact and good flexibility, and is easy to avoid huge losses of PCB production line, It has high economic value.

3) Computer vision inspection technology (AVI):

This technology is developed on the basis of computer vision. It is an emerging high-tech industrial detection technology. It realizes three-dimensional measurement of the size and spatial position of the measured object through the image sensor. The obtained data is compared or extracted with the fault image data in the computer, and guides the action of electronic equipment according to the detection parameters. It has high timeliness and Strong resistance.

The above is an overview of PCB defect detection technology.

This article is integrated from CSDN and Baidu Encyclopedia

Editor ajx