What are common PCB problems and how to prevent them?

What are common PCB problems and how to prevent them?

Minimizing failures is the primary goal of PCB manufacturers serving critical industries rather than critical industries. A deep understanding of common failures, root causes and preventive actions is one way to ensure high quality PCB assembly. Due to the increasing density of these problems, the probability of PCB failure is high. If care is not taken, it will affect the functionality of the final product. Would you like to know about six common PCB manufacturing mistakes? Or how to prevent these manufacturing errors? This article will answer these questions in detail.

6 Common PCB Assembly Defects to Avoid

Below are some common defects found in printed circuit board assemblies and their corrective actions.

1. Solder bridge: This is the most common type of defect in PCB assemblies. Solder bridging, sometimes called a short, occurs when solder crosses an abnormal connection between one lead and another or two or more adjacent traces. Their small size makes them difficult to detect. If these shorts are not detected during board inspection, they can seriously damage components, such as burnt or burnt parts and traces. However, there are several ways to avoid this problem, such as adding solder mask between pads, ensuring zero clearance between PCB and stencil, etc.

2. Plating voids: Plated through holes are important holes in printed circuit boards because they pass current from one side of the board to the other through the holes. The walls of these holes are plated during the PCB manufacturing process. Before electroplating, the board is made conductive from top to bottom by copper deposition. During this process, electroless copper is attached to the edges and holes of the circuit board. Problems with copper deposition can lead to plating voids, which means the walls are not coated with copper evenly. These holes may affect the current flow. Plating voids can be caused by a number of reasons such as material contamination, air bubbles in the material, contaminated holes, etc. Therefore, due to air bubbles, contamination, and insufficient cleaning can be avoided by cleaning the material before drilling. Also, other defects can be avoided by following the instructions provided by the manufacturer.

3. Non-wetting: Non-wetting of alloy solder joints, also known as de-wetting, does not extend to PCB pads. Therefore, they cannot obtain good solder joint angles. Non-wetting can occur when solder partially covers the board surface while leaving exposed copper. This directly affects the quality of the solder joints. This PCB problem can be avoided by paying close attention to the storage environment of the PCB components. Make sure they meet the standards for humidity and temperature. Also, avoid using PCBs that have been stored for a long time without any protective covers or sheets.

4. Acid traps: During assembly, via positioning may cause solder to leak through the pads. This can be solved by using non-conductive epoxy or applying solder mask to the holes.

5. Physical damage: The failure of the PCB is related to physical damage, which is caused by environmental stress or during the SMT manufacturing process. The most common cause of PCB failure is leaving the board in the prototyping stage. Damage to physical components or parts is imperceptible and cannot be repaired. So there is no other option than to replace the PCB.

6. Electromagnetic Issues: Electromagnetic Interference and Electromagnetic Compatibility are two common terms associated with PCBs. The term Electromagnetic Compatibility (EMC) is the term used to generate and propagate electromagnetic energy, while Electromagnetic Interference refers to the damaging effects of EMC. These problems are due to some possible design flaws. Electromagnetic interference can be reduced by increasing the ground area of the PCB.