Printed circuit boards are the heart of all electronic components. These components make sure the smooth working of any electronic gadgets. So if a minor fault occurs in circuit boards, the devices most often stop working. PCB problems can become extremely critical and enigmatic if you do a slight mistake during the PCB manufacturing process.
In this article, we will elaborate in detail different faults in the printed circuit board and their possible solutions. During PCB manufacturing and assembly process, you should keep these problems in mind and try to avoid these as much as possible. Let’s try to understand all the problems and their solutions.
The Common Flaws of PCB Manufacturing
Here are the most common PCB fault, you should be familiar about:
Burnt Circuit Board
During the manufacturing process, the board and high temperature are the companions throughout the process. Therefore, it is quite obvious for PCB components to burn because every component can resist to a certain amount of heat. There should be enough space between different components otherwise they will burn. So it is important for PCB manufacturing companies to apply suitable temperature and appropriate space around the components.
Poorly Manufactured Components
It is another most remarkable problem with PCBs. This problem will occur if an inexpert person manufactures PCBs. Due to this problem, you will notice loose components, residual flux, connection troubles or bad solder. The flux is a soldering substance and can damage the PCB if you leave it on the board.
Poor soldering can lead to a disastrous situation. Cold soldering occurs when a technician doesn’t heat the solder properly. Moisture also can affect the soldering process, resulting in poor connect that further leads to components burning.
There are different environmental factors that can destroy PCBs such as cold, heat, dust, and moistures. For example, moisture could lead to corrosion, oxidation or rust. After building up an excessive amount of heat can clog the board causing it to overheat.
It is another most popular issue with PCBs and unfortunately, it is beyond your control. It is an obvious case that when components get older, they lose their quality resulting in the breakdown of the PCBs. The only thing you can do is to replace the aged component or rebuild a new board.
Sometimes PCB manufacturing machines puncture the important PCB’s materials during drilling that follow up with including a copper layer with an electroplating process. This process, referred to as deposition, adds a copper layer on the PCBs. Through the deposition, you can create holes in plating that prevents electric current sometimes from passing through holes and create problems in PCB working.
During PCB manufacturing and assembly China, solder mask or minute wedges of copper, commonly known as slivers, create several PCB problems. Sometimes, a solder mask or a thin piece of copper gets etched away and detaches in this process instead of dissolving that creates problems.
Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) are the two most common PCBs issues. EMC invites, generates and propagates electromagnetic energy. EMI is the damaging and unwanted effects from the EMC. These problems occur due to design flaws, resulting in a defective board.
Several types of chemicals are used in the entire PCB manufacturing process. Although different steps make sure the chemical cleaning, there are still chances of small chemical traces being left behind. If you don’t clean chemicals properly, they can cause short-circuiting and corrosion.
Not Using a DFM
Design for Manufacturability is a process used to inspect the layout of the board and to resolve all arising issues during the assembly process. If you don’t use DFM, it means you are missing potential errors that can be fixed before PCB assembly.
During the etching process, acid traps stay in the corner for a long time span than the design asks for. Therefore, the acid eats away more materials than planned. So this results as compromised connections or defects in circuits.
Insufficient Copper-to-Edge Clearance
Copper is an active and the most useful component of PCB because it is a conductive metal. Copper is vulnerable to corrosion so it also creates numerous PCB problems.
How to Find a Flaw on PCB?
Some PCB problems are very obvious so it is not necessary to be an engineer or a technician to find out that issue. A simple problem in your computer and any other gadgets can cause a PCB not to work. So just your visual inspection of any infected PCB could save your time, money, and trip for repairing.
You don’t need to use any PCB fault-finding equipment. You just need to power off your system and have a look for PCB fault finding. Follow the following steps to find a fault on PCB.
I. First of all, you should make sure that all circuit boards are plugged in properly.
Different CB’s contain multi-pin edge connectors. Sometimes when you move your device, connectors become loose. So if you tight them again, they will start working appropriately.
II. Check different plug-in components one by one.
Some chipboards such as piggyback or daughter boards become loose or dirty. Moreover, pins can become corroded so clean them all and pushing them gently so that they become seated properly.
III. Look at the board carefully for water and other objects like paper, clips and other similar objects on the circuit board.
Sometimes, such material can stop PCB from working.
IV. If the circuit board doesn’t contain dust or corrode pins, it’s time to check all secondary wires.
Pull them off and examine them carefully. If you find any wire damaged, try to replace them otherwise plug them as it is after cleaning.
V. You should also examine the entire printed board for broken or burned components or wire.
You should also check the little metal lines that connect different components on both sides of the circuit board together. When components burn, they can smoke so you should also check for any discolored or swollen components.
VI. Looks for all cracks on the printed circuit board carefully.
Don’t ignore even a hairline crack during PCB fault location, because even this minor damage can stop PCB working.
If you don’t find any issue in the circuit board, you should consult the PCB fault tester. There can be another issue as we have mentioned in the previous section. For example, if there is a chemical leakage electromagnetic issue, you can’t detect that easily so you will have to go to a technician or an engineer.
Causes of PCB Failure
The Printed Circuit Board is an integral component in all electronic devices. We have described in detail different faults of PCBs in the previous section. PCB failure analysis shows that there are many issues that occur just because of the technician’s careless. For example, if a technician doesn’t solder the components properly, it means there will be a poor connection between different components that will lead to damage.
How to avoid different flaws during PCB manufacturing
One of the main goals for every PCB manufacturing company is to minimize and prevent different types of assembly faults before appearing on the circuit board. This process is extremely important and gives surety of the highest possible quality of the PCBs. As it is a fact that printed circuit boards have very complex designs and the chance of PCB failure increases with the design complexity. If you commit a minor mistake or don’t care properly, it will definitely lead to PCB failure. So all PCB manufacturing companies try their best to prevent such failures. Here are the most common PCB failure and their solution:
Design for Manufacturability Checks
It is the most common PCB check that really helps in reducing the risk of different PCB assembly faults. Design for Manufacturability is a technique used to examine the layout of the circuit board and to resolve all arising issues during the assembly process. If you don’t use DFM, it means you are missing potential errors that can be fixed before PCB assembly.
It is another PCB assembly testing technique used to check the leadless parts of PCBs such as BGA components. This inspection process makes sure the proper soldering.
Sometimes circuit becomes short during assembly due to insufficient solder mask between pins. Another major reason for short-circuiting is when you don’t properly distribute the weight of the components during designing of the board. While designing the pads, it is extremely important to have enough space between components and the solder mask layer. Sometimes component alignment issues occur just because of not implementing a proper X-Y file because it is remarkably important for SMT assembly.
Hole in Pad
If your design has different holes in pads, also known as Active Pads, there is a high risk of solder leakage through these holes during assembly. To avoid such leakage, sometimes a nonconductive epoxy is utilized which is very costly. Instead of epoxy, you can fill these holes with solder mask because it is not risky for the circuit board.
If traces are too close to the corner of the circuit board, it can damage the PCB during routing. In this situation, any part of the coating that protects copper by interacting with the environment from corrosion can be trimmed. If trimming occurs, the copper would be exposed. So there are high chances of interaction between the copper and any other conducting material which leads to the short-circuiting. If the PCB protection board fails, a bystander can have an electric shock. For this reason, there must be minimum clearance for the specific type of board that is being fabricated or adhered to as well.
If there is insufficient copper plating on the inside walls of holes on the circuit board, it can make the boards defective because electric current will be unable to pass between different layers. You should make sure that all holes are properly cleaned and current will be able to pass after drilling. This will help to prevent any air bubble or other contamination inside the holes.
De-Wetting / Non-Wetting
When molten solder covers a pad or lead and then leaves behind a mound of solder on the circuit board, it is known as De-Wetting. Non-Wetting occurs when the solder partially covers the surface instead of covering the required surface. It is extremely easy to resolve both issues. You just have to make sure that the required surface has been covered with solder. After covering an entire pad, don’t leave a mound of solder on the circuit board. Clean that when needed.
How to Protect PCB?
Printed circuit boards are extremely crucial components of all electronic devices. So PCB protection is really important for gadget’s smooth working.
The most common method that is used to protect PCB is PCB protection coating. For example, a green or red-colored coating is used to cover copper. The coating protects the copper from corrosion and protects it from soldering when the board is populated. There are different methods to coat the copper. For example, PCB protection spray is used for coating.
Another popular method used for PCB protection is a glob top. This method is typically used when PCB produced in large quantities. In this process, different silicon dies are placed directly on the circuit board because it reduces the cost of the IC packaging. A glob of encapsulating material is placed on the top of the PCB to protect the raw die. It appears as a black blob on the PCB.
How does MOKO Technology decrease and solve such Flaws
MOKO Technology is an advanced PCB manufacturing company that contains a team of proficient engineers. All problems that lead PCB to failures are due to the carelessness of technicians or the usage of poor components. Lets’ understand this with examples:
Poorly Manufactured Components
This issue will occur if an unskilled person manufactures PCBs. Due to this problem, you will see loose components, residual flux, connection troubles or bad solder. PCB manufacturing takes place under the expert team of engineers so manufactured components of MOKO technology will be up to the mark.
Poor soldering can lead to a catastrophic situation. Bad soldering is another example of an unskilled manufacturing team. So an expert team of MOKO technology doesn’t leave any room for improvement while PCB manufacturing. So no such issue occurs when you purchase PCB from MOKO technology.
Burnt Circuit Board
Circuit board burns due to two basic reasons. First, if you apply high voltage, PCB will burn. Second, if the manufacturer uses low-quality components during the manufacturing process, the circuit board will burn. Every component works on a specific voltage so you should apply a suitable voltage. MOKO Technology Company uses the best quality components so there are no such chances for burning circuit board.
So overall, we have explained different flaws, how to find out PCB faults and their possible solution. If you really want to avoid PCB failure, you should always purchase PCB from a trustworthy company that provides quality products. One of the most remarkable companies in PCB manufacturing is MOKO technology. We suggest you purchase PCBs from MOKO technology to avoid severe loss.