The failure of PCBs is costly and, if not handled properly, can compromise the entire system. In many ways, the printed circuit board acts like the spine of any electronic device. It ensures inter-component communication and coordination is smooth.
Most custom-printed circuit boards undergo extensive engineering design but can still experience functional failures, inefficiencies, complete breakdowns, and system malfunctions. Addressing and understanding the root cause of PCB failure is essential to assist engineers and printed circuit board manufacturers in strengthening assembly and design improvements.
Poor design, unsatisfactory manufacturing, degradation of materials, or environmental conditions can all lead to PCB failure. Timely diagnosing problems with a board’s functionality using effective PCB failure analysis strategies can reduce product failure risks, loss of resources, and time.
This blog will discuss the most effective practices on how to prevent PCB failure, conduct a thorough failure analysis, and identify primary causes that contribute to the failure of printed circuit boards.
Are you on the lookout for failure-resistant, high-quality PCBs? Feel free to get in touch with PCB Runners whenever you need expert consultation for circuit board manufacturing solutions.
What Causes PCB Failure?
PCBs may fail due to several reasons, such as the design of the board, material selection, manufacturing defects, and the surrounding environment. Below are some of the most common reasons for PCB failure:
A Poor Design of the PCB
- Every trace width is designed with the goal of being as narrow as possible, leading to overheating.
- Components are placed in a way that creates interference, which is not the intended purpose.
- Thermal relief systems are lacking in structures to prevent heat containment.
- Conductive paths are too close together to allow for short-circuit bypass.
Manufacturing Issues
- Soldering Problems – Cold joints, bridging, and excess or insufficient soldering may lead to failures in a particular connection.
- Delaminations – Separation of the levels of a PCB as a result of poor lamination.
- Via Problems – Not plating or drilling alignment affecting the electric link.
- Copper Trace Damage – Weak tracing snapping from forces.
Stress Factors and Aging
- High amounts of heat and humidity can burst the material, leading to failure.
- Movement and shaking – repeated physical stress leads to weakened joints.
- Corrosion- Damage from moisture and chemicals degrades conductive materials.
- Electrostatic Discharge (ESD) – Dangers for circuits and components.
Overstraining Electricity (EOS) and Power Problems
Suffering damage from overvoltage or excessive current. Inadequate grounding leads to havoc and false command behavior within the circuits. Damage resulting from reversing polarity connections to the parts of the PCB.
1. Contamination & Impurities
- Chemical contaminants and dust can disrupt circuit performance due to the presence of flux residues.
- Corrosion and oxidation are a result of poor post-cleaning practices after manufacturing.
2. PCB Failure Analysis Techniques
Upon failure, each printed circuit board is analyzed with specific techniques aimed at reasoning for the failure and what rectifications need to be done. The most common approaches are:
3. Visual Inspection
Look for signs like broken traces, misaligned components, burnt areas, and discoloration.
4. X-ray Inspection
For inspection of connections on multilayer printed circuit boards, solder joints, and vis, X-ray machines are employed.
5. Thermal Imaging
Thermal Imaging is used for locating overheating parts, hotspots, and areas of weak thermal control.
6. Electrical Testing
Continuity Testing: Checking connections to ensure there are not any breaks in them.
Functional Testing: Ensuring that the PCB provides the expected operation.
In-Circuit Testing (ICT) – Testing on the components and their interconnections.
7. Scanning Electron Microscopy (SEM)
SEM is used for capturing detailed images aimed at identifying cracks, delamination, and other micro-defects embedded in the materials of the PCB.
8. Analyzing Solder Joints
Feedback from bridging, modifying poor refusals, and cold solder joints should be confirmed in solder joint verifications.
Prevention of Failures in PCBs
To enhance the reliability and durability of a printed circuit board, the following failure prevention techniques should be employed.
1. Design for Reliability
- Increased reliability starts with using proper routing and thermal management of the board’s traces on PCB design software.
- DFM or Design for Manufacturing guidelines have to be followed so that the assembly process is free of assembly defects.
- Trace width and space allowance must be sufficient to avoid overheating.
2. Choose High-Quality Materials
- Choose a PCB circuit board manufacturer that uses quality substrate materials.
- For multilayer printed circuit boards, use multilayered boards for more complex designs that require more durability.
- Use materials that are more resistant to heat, like FR4 and polyimide, or even ceramic substrates, for better longevity.
Improve PCB Manufacturing & Assembly Processes
Work with other trusted PCB circuit board manufacturers to ensure strict quality control standards are being followed.
- Check for proper solder mask application that could lead to oxidation and contamination.
- Use automated optical inspection (AOI) to check for defects before the end of production.
Enhance Thermal Management
- Use thermal vias and heat sinks to dissipate heat from high-powered components.
- Position temperature-controlling components near the heat-generating components.
- Use thermal relief pads to avoid the build-up of critical excessive heat in sensitive areas.
1. Protect Against Environmental Damage
- Deny moisture protection can be applied by conformal coat coverings alongside chemical and dust shielding.
- Prevention against oxidation for contact nodes can be done using gold or silver plating.
- If the PCB is in harsh conditions, protect the design for IP-rated enclosures.
2. Prevent Electrical Failures
- Remove the possibility of electromagnetic interference (EMI) through good grounding and shielding implementation.
- Innumerous fuses, varistors, and even TVS are diodes designed for overvoltage protection.
- Avoid voltage changes by making sure the power supply circuit is intact and validated.
3. Conduct Rigorous Testing and Ensure Quality Control
- Perform functional, burn-in, and reliability testing prior to commencing mass production.
- Multilayer PCBs with internal layers require X-ray inspection and ultrasonic testing for hidden defects.
- Quality standards for PCB fabrication set forth by IPC-A-600 and IPC-6012 are mandatory.
Future Trends in PCB Reliability & Failure Prevention
The evolution of the electronics industry is shifting the focus towards newer technologies for preventing failures in PCBs during manufacturing. Emerging trends include:
1. AI-Based PCB Design and Testing
Before the manufacturing stage, AI algorithms can aid in identifying potential design flaws.
Early detection of potential failures is now possible through machine-learning-based predictive maintenance.
2. Advanced PCB Materials
The development of flexible PCBs includes self-healing capabilities.
Graphene-based PCBs are being adopted due to their high conductivity and the ability to dissipate heat efficiently.
3. 3D Printed PCBs
Custom custom-made precise PCBs can now be readily designed.
Enhanced rapid prototyping capabilities and reduced material waste have been achieved.
4. Improved Conformal Coatings
Moisture and contamination-resistant nano coatings offer better protection.
Durability is improved with faster production by using UV-curable coatings.
Manufacturers are able to build PCBs with lower failure rates by increasing their resilience to harsh operating conditions through newly invented innovations in PCBs.
Conclusion
Diagnosing the faults and understanding the reasons behind a PCB failure help in improving its reliability. This could be caused by a design error, environmental factors, excessive electrical loading, or selection of substandard materials, but all can be worked on to ensure effective PCBs remain durable.
At PCB Runners, we take pride in providing preeminent custom printed circuit boards as per industrial requirements, which ensures the best performance and tailoring of failure avoidance techniques in each application.
High-quality PCBs are custom-made for your specific needs. We offer multilayered PCBs paired with refined failure analysis, making a trusted source for all your requirements. Contact Us now to discuss your projects further.
Frequently Asked Questions (FAQs)
1. What usually causes the failure of circuit boards?
Factors such as an overloaded power supply, overheating and external stress, unsatisfactory design and manufacturing, as well as contamination tend to cause the most faults.
2. What are proposing capturing techniques for circuit failure?
The use of high-grade materials, proper management of thermal load, functional testing, and ample design modifications are bound to oppress failure.
3. How is the failure of a PCB diagnosed, and why is it essential?
Diagnosing issues to enhance dependability by means of visual inspection, electrical tests, x-ray examination, and material analysis constitutes failure analysis.
4. How does environmental stress affect the performance of a PCB?
Factors such as humidity, heat, vibration, and corrosive chemicals cause degradation of the insides of a PCB, leading to oxidation, cracks, or joint soldering failure.
5. Why are multilayer PCBs considered superior to their single-layer counterparts?
High-performance electronics require superior durability, signal integrity, and improved heat dissipation, a feature provided by multilayer PCBs.