How to detect the quality after laser welding of PCB circuit board?

With the continuous advancement of 5G construction, industrial fields such as precision microelectronics and aviation and Marine have been further developed, and these fields all cover the application of PCB circuit boards. At the same time of the continuous development of these microelectronics industry, we will find that the manufacturing of electronic components is gradually miniaturized, thin and light, and the requirements for precision are becoming higher and higher, and laser welding as the most commonly used processing technology in the microelectronics industry, which is bound to put higher and higher requirements on the welding degree of PCB circuit boards.

The inspection after the welding of PCB circuit board is crucial for enterprises and customers, especially many enterprises are strict in electronic products, if you do not check it, it is easy to have performance failures, affecting product sales, but also affecting the corporate image and reputation.

The following Fastline Circuits shares several commonly used detection methods.

01 PCB triangulation method

What is triangulation? That is, the method used to check the three-dimensional shape.

At present, the triangulation method has been developed and designed to detect the cross section shape of the equipment, but because the triangulation method is from different light incident in different directions, the observation results will be different. In essence, the object is tested through the principle of light diffusion, and this method is the most appropriate and most effective. As for the welding surface close to the mirror condition, this way is not suitable, it is difficult to meet the production needs.

02 Light reflection distribution measurement method

This method mainly uses the welding part to detect the decoration, the inward incident light from the inclined direction, the TV camera is set above, and then the inspection is carried out. The most important part of this method of operation is how to know the surface Angle of the PCB solder, especially how to know the illumination information, etc., it is necessary to capture the Angle information through a variety of light colors. On the contrary, if it is illuminated from above, the measured Angle is the reflected light distribution, and the tilted surface of the solder can be checked

03 Change the Angle for camera inspection

Using this method to detect the quality of PCB welding, it is necessary to have a device with a changing Angle. This device generally has at least 5 cameras, multiple LED lighting devices, will use multiple images, using visual conditions for inspection, and relatively high reliability.

04 Focus detection utilization method

For some high-density circuit boards, after PCB welding, the above three methods are difficult to detect the final result, so the fourth method needs to be used, that is, the focus detection utilization method. This method is divided into several, such as the multi-segment focus method, which can directly detect the height of the solder surface, to achieve high-precision detection method, while setting 10 focus surface detectors, you can obtain the focus surface by maximizing the output, to detect the position of the solder surface. If it is detected by the method of shining a micro laser beam on the object, as long as the 10 specific pinholes are staggered in the Z direction, the 0.3mm pitch lead device can be successfully detected.