As engineers, we have thought of all the ways that the system can fail, and once it fails, we are ready to repair it. Avoiding faults is more important in PCB design. Replacing a circuit board that is damaged in the field can be expensive, and customer dissatisfaction is usually more expensive. This is an important reason to keep in mind the three main reasons for PCB damage in the design process: manufacturing defects, environmental factors and insufficient design. Although some of these factors may be out of control, many factors can be mitigated during the design phase. This is why planning for a bad situation during the design process can help your board perform a certain amount of performance.
01 Manufacturing defect
One of the common reasons for PCB design board damage is due to manufacturing defects. These defects can be difficult to find, and even more difficult to repair once discovered. Although some of them can be designed, others must be repaired by a contract manufacturer (CM).
02 envirnmental factor
Another common cause of PCB design failure is the operating environment. Therefore, it is very important to design the circuit board and the case according to the environment in which it will operate.
Heat: Circuit boards generate heat and are often exposed to heat during operation. Consider whether the PCB design will circulate around its enclosure, be exposed to sunlight and outdoor temperatures, or absorb heat from other nearby sources. Changes in temperature can also crack the solder joints, base material and even the housing. If your circuit is subject to high temperatures, you may need to study through-hole components, which usually conduct more heat than SMT.
Dust: Dust is the bane of electronic products. Ensure that your case has the correct IP rating and/or select components that can handle the expected dust levels in the operating area and/or use conformal coatings.
Moisture: Humidity poses a great threat to electronic equipment. If the PCB design is operated in a very humid environment where the temperature changes rapidly, moisture will condense from the air onto the circuit. Therefore, it is important to ensure that moisture-proof methods are incorporated throughout the circuit board structure and before installation.
Physical vibration: There is a reason for sturdy electronic advertisements that people throw them on rock or concrete floors. During operation, many devices are subject to physical shock or vibration. You must choose cabinets, circuit boards and components based on mechanical performance to solve this problem.
03 Non-specific design
The last factor of PCB design board damage during operation is the most important: design. If the engineer’s purpose is not specifically to meet its performance goals; including reliability and longevity, this is simply out of reach. If you want your circuit board to last a long time, make sure to select components and materials, lay out the circuit board, and verify the design according to the specific requirements of the design.
Component selection: Over time, components will fail or stop production; however, it is unacceptable for this failure to occur before the expected life of the board expires. Therefore, your choice should meet the performance requirements of its environment and have a sufficient component life cycle during the expected production life cycle of the circuit board.
Material selection: Just as the performance of components will fail over time, so will the performance of materials. Exposure to heat, thermal cycling, ultraviolet light, and mechanical stress can cause circuit board degradation and premature failure. Therefore, you need to select circuit board materials with good printing effects according to the type of circuit board. This means considering material properties and using the most inert materials that are suitable for your design.
PCB design layout: Unclear PCB design layout may also be the root cause of circuit board failure during operation. For example, the unique challenges of not including high-voltage boards; such as high-voltage arc tracking rate, may cause circuit board and system damage, and even cause injury to personnel.
Design verification: This may be the most important step in producing a reliable circuit. Perform DFM checks with your specific CM. Some CMs can maintain tighter tolerances and work with special materials, while others cannot. Before you start manufacturing, make sure that CM can manufacture your circuit board the way you want, which will ensure that the higher quality PCB design A will not fail.
It is not interesting to imagine the worst possible scenario for PCB design. Knowing that you have designed a reliable board, it will not fail when the board is deployed to the customer. Remember the three main reasons for PCB design damage so that you can smoothly obtain a consistent and reliable circuit board. Make sure to plan for manufacturing defects and environmental factors from the beginning, and focus on design decisions for specific cases.