Common PCB assembly errors

High-quality PCB manufacturing and assembly play a key role in the reliability of the final product. As PCB designs become more complex, the lack of proper planning can lead to high failure rates. Here are six common PCB manufacturing errors that can be avoided with a little caution.

1.Lack of manufacturability check
The most common mistake is not to check early on manufacturability. When performing these checks during the design phase itself, you can ensure that any necessary corrections are made to avoid costly errors during the manufacturability phase.

DFM allows manufacturers to study product design in terms of size, materials, functions, etc., and may also find alternative best manufacturing methods. As a result, design flaws are discovered before production starts, helping to save time and money. On the other hand, the lack of these checks can lead to costly production interruptions and wasteful operations.
2. Welding bridge
This is one of the most common defects in PCB assembly, and generally occurs when two or more pads are connected to form a bridge. The main problem with welding bridges is that they are difficult to detect due to their size. Welding bridges are known to occur mainly for the following reasons:
● Insufficient solder layer between pads
● The gap between the shims is too small
● Components are placed incorrectly
● Improper seal between stencil and bare board during printing
Due to component burning, undetected solder bridges can cause PCB damage. Therefore, pay attention to the above factors to prevent solder bridging.

3.Plating holes
The uneven copper coating on the inner wall of the hole on the PCB can cause the current flowing through the via to be affected. This can be caused by a number of factors, such as:
● Material contamination
● Contaminated hole
● Air bubbles in the material
To ensure that plating voids do not occur, the manufacturer's instructions must be fully followed during use.

4.Dry / non-wet
Wetting solder is the application of molten solder to a surface, leaving an irregularly shaped solder pile when it is withdrawn. Non-wetting solder refers to a state where the molten solder is partially adhered to the surface and the metal is still partially exposed. To avoid these situations, it is important to ensure that the components are not expired and that the magnetic flux is not overused.
5.Electromagnetic problems
Design defects often cause PCB damage due to the damaging effects of electromagnetic interference. Therefore, it is very important to keep this in mind and work on areas such as increasing the PCB ground area so that you can reduce electromagnetic interference and work your PCB efficiently.

6.Physical damage
Usually, physical damage caused by environmental pressure during the manufacturing process also causes PCB failure. For example, the PCB dropped during prototyping. This may damage the components. A factor that adds complexity is that sometimes the damage may not be physically visible. In this case, the only option is to replace the PCB.

Although the above list is not comprehensive and there are many factors that can cause PCB problems, there are plans to easily avoid these most common problems. In fact, as the size of PCBs becomes smaller and more complex, there are many aspects that require close attention to ensure success.
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