In the process of PCB design and production, engineers must not only prevent accidents during PCB board manufacturing but also avoid design errors.
**Problem 1: PCB Board Short Circuit**
This issue is one of the most common faults that can directly prevent the PCB board from functioning. There are several potential causes for this problem, which we will analyze individually.
The primary cause of PCB short circuits is improper solder pad design. In such cases, the round solder pads can be modified to an oval shape, which helps increase the distance between pads and reduces the risk of a short circuit.
Another common cause of short circuits is poor orientation of the PCB components. For example, if the pins of an SOIC package are aligned parallel to the solder wave, it can easily lead to a short circuit. To avoid this, the component’s orientation should be adjusted so that the pins are perpendicular to the solder wave.
A further potential cause of short circuit failure is the use of automatic insertion components with bent leads. According to IPC standards, the pin length should be less than 2mm. If the angle of the bent lead is too large, there is a risk of parts falling off, which could cause a short circuit. In this case, the solder joint should be positioned more than 2mm away from the circuit to ensure proper functionality.
**In addition to the three reasons mentioned above, there are other factors that can cause short-circuit failure in a PCB. These include oversized holes in the substrate, insufficient temperature in the soldering furnace, poor solderability of the board, failure of the solder mask, surface contamination, and other common issues. Engineers can compare these potential causes with the observed failure conditions to systematically rule them out and perform necessary inspections.**
**Problem 2: Dark and Grainy Solder Joints on the PCB**
**The appearance of dark or grainy solder joints on a PCB is often due to contamination in the solder or the presence of excessive oxides in the molten solder, which leads to brittle solder joints. It’s important not to confuse this issue with dark solder joints caused by using solder with low tin content.**
**Another possible cause is a change in the solder composition during manufacturing, leading to an excessively high impurity content. In such cases, adding pure tin or replacing the solder may resolve the issue. Stained glass can cause physical changes to the fiber structure, such as layer separation, but this is not related to poor solder joints. The actual cause is usually excessive substrate heating, and it can be mitigated by reducing the preheating and soldering temperatures or increasing the substrate speed.**
**Problem 3: PCB Solder Joints Turning Golden Yellow**
**Normally, the solder on a PCB appears silver-gray, but occasionally, golden yellow solder joints may appear. This issue is typically caused by excessively high temperatures. The solution is to simply lower the temperature of the soldering furnace.**
**Problem 4: Environmental Impact on the PCB**
**The PCB’s structure makes it vulnerable to damage when exposed to unfavorable environmental conditions. Extreme temperatures or temperature fluctuations, excessive humidity, intense vibrations, and other environmental factors can degrade the board’s performance or even render it unusable. For example, temperature changes can cause board deformation, leading to destroyed solder joints, bent boards, or broken copper traces.**
**Moisture in the air can lead to oxidation, corrosion, and rust on metal surfaces, such as exposed copper traces, solder joints, pads, and component leads. Accumulation of dirt, dust, or debris on the surface of components or the PCB can restrict airflow and cooling, causing the PCB to overheat and its performance to degrade. Vibration, drops, impacts, or bending of the PCB can cause deformations and cracks, while high current or overvoltage can break down the PCB or lead to rapid aging of the components and paths.**
**Problem 5: PCB Open Circuit**
**An open circuit occurs when the trace is broken or when solder is only on the pad and not properly connected to the component leads. In this case, there is no electrical connection between the component and the PCB. Like short circuits, open circuits can arise during the production process or during soldering and other operations. Mechanical factors such as vibration, stretching, dropping, or other forms of deformation can damage the traces or solder joints. Similarly, chemical exposure or moisture can cause wear on the solder or metal parts, leading to broken component leads.**
**Problem 6: Human Error**
**A significant proportion of defects in PCB manufacturing are due to human error. In fact, incorrect production processes, improper component placement, and non-compliant manufacturing specifications account for up to 64% of avoidable product defects. The likelihood of errors increases with circuit complexity and the number of production steps involved, especially with densely packed components, multiple circuit layers, fine traces, surface-mounted components, and power and ground planes.**
**Although every manufacturer or assembler strives for defect-free PCBs, the complexity of design and the multitude of production issues contribute to persistent PCB problems that require careful attention.**
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
**Problem 1: PCB Board Short Circuit**
This issue is one of the most common faults that can directly prevent the PCB board from functioning. There are several potential causes for this problem, which we will analyze individually.
The primary cause of PCB short circuits is improper solder pad design. In such cases, the round solder pads can be modified to an oval shape, which helps increase the distance between pads and reduces the risk of a short circuit.
Another common cause of short circuits is poor orientation of the PCB components. For example, if the pins of an SOIC package are aligned parallel to the solder wave, it can easily lead to a short circuit. To avoid this, the component’s orientation should be adjusted so that the pins are perpendicular to the solder wave.
A further potential cause of short circuit failure is the use of automatic insertion components with bent leads. According to IPC standards, the pin length should be less than 2mm. If the angle of the bent lead is too large, there is a risk of parts falling off, which could cause a short circuit. In this case, the solder joint should be positioned more than 2mm away from the circuit to ensure proper functionality.
**In addition to the three reasons mentioned above, there are other factors that can cause short-circuit failure in a PCB. These include oversized holes in the substrate, insufficient temperature in the soldering furnace, poor solderability of the board, failure of the solder mask, surface contamination, and other common issues. Engineers can compare these potential causes with the observed failure conditions to systematically rule them out and perform necessary inspections.**
**Problem 2: Dark and Grainy Solder Joints on the PCB**
**The appearance of dark or grainy solder joints on a PCB is often due to contamination in the solder or the presence of excessive oxides in the molten solder, which leads to brittle solder joints. It’s important not to confuse this issue with dark solder joints caused by using solder with low tin content.**
**Another possible cause is a change in the solder composition during manufacturing, leading to an excessively high impurity content. In such cases, adding pure tin or replacing the solder may resolve the issue. Stained glass can cause physical changes to the fiber structure, such as layer separation, but this is not related to poor solder joints. The actual cause is usually excessive substrate heating, and it can be mitigated by reducing the preheating and soldering temperatures or increasing the substrate speed.**
**Problem 3: PCB Solder Joints Turning Golden Yellow**
**Normally, the solder on a PCB appears silver-gray, but occasionally, golden yellow solder joints may appear. This issue is typically caused by excessively high temperatures. The solution is to simply lower the temperature of the soldering furnace.**
**Problem 4: Environmental Impact on the PCB**
**The PCB’s structure makes it vulnerable to damage when exposed to unfavorable environmental conditions. Extreme temperatures or temperature fluctuations, excessive humidity, intense vibrations, and other environmental factors can degrade the board’s performance or even render it unusable. For example, temperature changes can cause board deformation, leading to destroyed solder joints, bent boards, or broken copper traces.**
**Moisture in the air can lead to oxidation, corrosion, and rust on metal surfaces, such as exposed copper traces, solder joints, pads, and component leads. Accumulation of dirt, dust, or debris on the surface of components or the PCB can restrict airflow and cooling, causing the PCB to overheat and its performance to degrade. Vibration, drops, impacts, or bending of the PCB can cause deformations and cracks, while high current or overvoltage can break down the PCB or lead to rapid aging of the components and paths.**
**Problem 5: PCB Open Circuit**
**An open circuit occurs when the trace is broken or when solder is only on the pad and not properly connected to the component leads. In this case, there is no electrical connection between the component and the PCB. Like short circuits, open circuits can arise during the production process or during soldering and other operations. Mechanical factors such as vibration, stretching, dropping, or other forms of deformation can damage the traces or solder joints. Similarly, chemical exposure or moisture can cause wear on the solder or metal parts, leading to broken component leads.**
**Problem 6: Human Error**
**A significant proportion of defects in PCB manufacturing are due to human error. In fact, incorrect production processes, improper component placement, and non-compliant manufacturing specifications account for up to 64% of avoidable product defects. The likelihood of errors increases with circuit complexity and the number of production steps involved, especially with densely packed components, multiple circuit layers, fine traces, surface-mounted components, and power and ground planes.**
**Although every manufacturer or assembler strives for defect-free PCBs, the complexity of design and the multitude of production issues contribute to persistent PCB problems that require careful attention.**
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
