What are the methods for testing the quality of circuit boards after welding?

Date：2022-09-28 11:50:39Views：808

With the increase of electronic equipment, there are more and more PCBA processing industries. The inspection of PCBA circuit boards after welding is very important for PCBA processing manufacturers and customers. In particular, many customers have strict requirements for electronic products. If they do not check, performance failures are likely to occur, affecting product sales, as well as corporate image and reputation. Then, how to detect the quality of PCBA circuit board after welding? Next, let's introduce it to you.

Four Methods for Detecting the Quality of PCB after Welding

1、 PCB triangulation

What is triangulation? This is the method used to check the solid shape. At present, the triangulation detection method has been developed and used, and the equipment that can detect the section shape has been designed. However, because this triangulation detection method is incident from different light, the observation results will be different in different directions. In essence, all objects are tested by the principle of light diffusion, which is the most appropriate and effective method. As for the condition that the welding surface is close to the mirror surface, this method is not suitable and it is difficult to meet the production demand.

2、 Measurement of light reflection distribution

This method mainly uses the welding position to detect the decoration, incident light inward from the inclined direction, set up TV camera above, and then check it. The most important part of this operation method is how to know the surface angle of PCB solder, especially how to know the illumination information. It is necessary to capture the angle information through various light colors. On the contrary, if it is illuminated from above, the measured angle is the reflected light distribution, and it is enough to check the inclined surface of solder.

3、 Change the angle for camera inspection

When using this method to detect the quality of the welded circuit board, it is necessary to have a device with a change angle. This device generally has at least 5 cameras, multiple LED lighting devices, multiple images, visual inspection conditions, and high reliability.

4、 Focus detection method

For some high-density circuit boards, it is difficult to detect the final results by the above three methods after the circuit boards are welded. Therefore, the fourth method, focus detection, is required. This method is divided into several, such as the multi segment focus method, which can directly detect the height of the solder surface and achieve high-precision detection. If 10 focus plane detectors are set at the same time, the focus plane can be obtained by calculating the maximum output to detect the position of the solder surface. If the detection is conducted by irradiating the object with a micro laser beam, the 0.3mm pitch lead device can be successfully detected as long as 10 specific pinholes are staggered in the Z direction.

To sum up, these are not all testing methods, nor are they absolute testing methods. If you want to 100% ensure that PCB is free of problems, you need to pay attention to early procurement, mid-term production and late inspection. Only through joint efforts in many aspects can you truly produce products that satisfy customers. Our company has a team of professional engineers and industry elites, and has built three standardized laboratories with an area of more than 1800 square meters, which can undertake a variety of test projects such as electronic component test verification, IC authenticity identification, product design material selection, failure analysis, functional testing, factory incoming material inspection and tape weaving.