PCB board in the design and production of the process will always encounter a variety of problems, such as dark and granular PCB board contact, bending and so on.
An open circuit occurs when the trace breaks, or when solder is only on the pad and not on the component lead. In this case, there are no adhesions or connections between the component and the PCB. Just like short circuits, these can also occur during manufacturing or welding or other operations. Vibrating or stretching circuit boards, dropping them, or other mechanical deforms can destroy traces or solder joints. Also, chemical or moisture can cause the solder or metal parts to wear down, which can cause component leads to break.
Dark and granular contacts appear on PCB board
The dark color or small granular contact problem on the PCB board is mostly due to the contamination of the solder tin and the excessive oxide mixed with the dissolved tin, which forms the solder joint structure too brittle. Be careful not to be confused with the dark color caused by the use of low tin content solder.
Another reason for this problem is that the solder itself used in the processing and manufacturing process changes in composition, too much impurity content, need to add pure tin or replace solder. Physical changes in the speckled glass fiber layers, such as separation between layers. But this is not a case of bad solder joints. The reason is that the substrate is heated too high, need to reduce preheating and soldering temperature or increase the speed of the substrate.
The PCB solder spots turn golden
Generally PCB solder is silver gray, but occasionally there are golden solder spots. The main reason for this problem is that the temperature is too high. At this time, only the tin furnace temperature can be lowered.
Bad boards are also influenced by the environment
Due to the structure of PCB itself, it is easy to cause damage to PCB board when it is in adverse environment. Extreme temperature or temperature change, humidity, high intensity vibration and other conditions are the factors that lead to the performance of the board to reduce or even scrap. For example, a change in ambient temperature may cause the board to deform. This will break the solder joints, bend the shape of the board, or may cause the copper traces on the board to break.
On the other hand, moisture in the air can cause oxidation, corrosion, and rust of metal surfaces, such as exposed external copper traces, solder joints, pads, and component leads. The accumulation of dirt, dust, or debris on the surfaces of components and circuit boards can also reduce the air flow and cooling of components, leading to PCB overheating and performance degradation. Vibrating, falling, hitting or bending a PCB can deform it and cause cracks, while large currents or overvoltages can cause a PCB to break down or cause rapid aging of components and channels.
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