How to judge the quality of PCB by appearance?

As an electronic product practitioner, we often need to check and evaluate the quality of PCB boards to ensure that our circuit design and manufacturing can operate normally. However, sometimes we do not have enough expertise and equipment to conduct in-depth testing and analysis. So, how to judge the quality of PCB boards by appearance? Let's share some of our experience and tips below.

1. Visual inspection

First, we can check the quality of PCB boards by observing their appearance with the naked eye. A good PCB board should have a neat appearance, no obvious scratches and deformations, and a smooth surface without impurities. If the appearance is not neat, with scratches and deformations, it is likely that there is a problem in the manufacturing process or the material quality is not up to standard.

2. Pad inspection

The pad is a very important part of the PCB board and is also a part that is vulnerable to damage. We can judge the quality of the PCB board by checking the quality of the pad. The pad should be flat, smooth, uniform in size, without tailing, and the BGA pad size should be uniform, without oxidation and warping. If the pad has problems such as oxidation and warping, it is very likely to affect the normal operation of the circuit; if the pad size is uneven and the BGA size is inconsistent, it is very likely to cause defects during SMT patching. Such problems are generally caused by the lack of detailed optimization of factory engineering processing data.

3. Detailed inspection

In addition to the above two inspections, we also need to pay attention to the details of the PCB board. For example, the circuit on the PCB board should be clear and precise; the gong board should be smooth and burr-free; there should be no open circuit or short circuit. If the circuit is not clear, or there is an open circuit or short circuit, such a PCB cannot be used. Although the gong board is not smooth, it does not affect the use function of the PCB, but it looks like the PCB is relatively low-end.

Through the above visual inspection, pad inspection and detailed inspection, we can preliminarily judge the quality of the PCB board. Of course, these methods are not 100% accurate. If we need more precise testing and analysis, we also need to use professional testing equipment and tools. However, through these simple methods, we can preliminarily judge the quality of the PCB board and provide some reference and guidance for us.