Typical PCB Defects: What Causes A Circuit Board To Burn?

What we cover in this blog?

• Printed Circuit Boards
• Common Reasons Behind PCB Failures
• Other Factors Causing PCB Failures
• Required Safety Measurements
• Testing of PCB

Printed Circuit Boards

A printed circuit board (PCB) is indispensable in nearly all electronic devices. Everything except the simplest electronics uses a board to connect and mechanically sync all product elements. A coffee maker may contain a small printed circuit board to connect its electronic control system, heater element, and display.

PCBs play a vital role in the functioning of devices as they provide mechanical support and connect all the components. Conductive tracks facilitate the flow of electricity through the board, enabling it to reach all the components. The components of various devices, such as the battery, resistors, LEDs, transistors, capacitors, etc., are soldered to the board to ensure they are electrically and mechanically fastened to the circuit.

PCBs are crucial to all electronics, including medical devices, wearables, satellites, and airplanes. Therefore, it is essential to comprehend the common causes of PCB failure and how to prevent them.

Common Reasons Behind PCB Failures

1. Environmental factors

Circuit board failure can be caused by heat, dust, moisture, accidental impact, power overload, lightning strikes, voltage surges, and electrostatic discharge (ESD) at the assembly stage. However, ESD is the most damaging cause of premature circuit board and component failure.

2. Poor quality components

Even PCBs with high-quality components can suffer from closely placed traces, bad soldering, poor connectivity, insufficient thickness, and counterfeit components such as right diodes. Ensuring proper component quality is essential, as subpar components and excessive flux residue can damage PCB, resulting in diminished performance, power failures, physical harm, and connectivity issues necessitating repairs.

3. Component design failure

Improper component spacing, power failure, machine overheats, human error, and extreme heat due to lack of space on the PCB are just a few things that can impact adjacent components in the design and manufacturing process.

4. Age

Replacing old components is more cost-effective than new PCB assembly to control costs caused by age-related failures in replacing components.

Other Factors Causing PCB Failures

1. Poor soldering

Proper soldering is crucial for successful PCB assembly. Insufficient heating can cause cold soldering and potential component failure-related burning up. Moisture can contaminate PCB pads and components, resulting in burning and connection issues. Defective soldering can be identified through visual or X-ray inspections.

2. Missing solder mask

To prevent accidental solder bridges, ensure solder masks are complete between pads. Review designs and choose a reputable contract manufacturer with good DFM check protocols to protect against electrocution and corrosion.

3. Copper-to-edge clearance

PCBs typically utilize copper foil, but it tends to rust and is quite soft. If the coating is trimmed too closely, it may expose the copper, leading to problems like short circuits and corrosion of adjacent components. To avoid this, the contract manufacturer will conduct a DFM (design for manufacturability) check to ensure that the copper-to-edge clearance adheres to acceptable standards.

4. Plating voids

To enable the flow of electric current, circuit boards require copper-coated holes. However, deposition issues can cause plating voids, resulting in faulty products and disrupted current flow. These issues can be prevented by following proper deposition methods, using coating materials, implementing cleaning procedures, and collaborating with an experienced PCB company.

5. Slivers

Slivers and solder masks play a critical role in PCB manufacturing, but they can pose challenges if they become detached or are cut too narrowly or deeply during the etching process. Such issues may result in unintended connections and significantly affect the board’s functionality.

6. Acid traps

‘Acid traps’ are acute angles in circuits that can cause corroded connections and faulty circuits during PCB etching.

7. Electromagnetic issues

EMC and EMI are circuit board design problems caused by electromagnetic energy. Excessive EMI can result in a PCBS failure. To reduce EMI, increase the ground area, avoid 90-degree angles, and use shielded cables and metallic packaging. Consult a PCB expert in harness cable assembly if issues arise during prototyping.

8. Starved thermals

Improperly connected thermals and thermal stress on a circuit board can cause problems during soldering and overheating, leading to damage. The solution is to replace the thermal due to manufacturing errors.

9. Burned circuit boards

During manufacturing, circuit boards may be exposed to high temperatures and the risk of overcrowding with essential components. This scenario can lead to component burnout and complicate diagnosing problems. It is paramount to uphold component quality and ensure adequate spacing to prevent overheating and safeguard the circuit boards from potential harm.

10. Chemical leakage

PCB board can experience chemical leakage due to various chemicals used during manufacturing. Although manufacturers strive to clean circuit boards thoroughly, trace amounts of chemical residues may remain. Over time, these residues can lead to corrosion and short-circuiting of the metal components on the boards.

Required Safety Measurements

• Certification:Certified Electronics Manufacturing Service Providers manufacture PCBs according to industry standards such as IPC-A-610. These certifications ensure high quality and strict adherence to safety measures.
• Training:Certified electronics manufacturing professionals ensure the avoidance of burnt components and circuit boards and the identification of safety issues.
• Equipment:Certified Electronics Manufacturing Service Providers utilize modern equipment and perform regular maintenance to prevent burnt circuit boards.
• Inspection:During and after manufacturing, PCBs undergo inspection to ensure they are free of defects that may result in a burnt circuit board.

Testing of PCB

Certified Electronics Manufacturing Service Providers, including wire harness companies in India, employ state-of-the-art equipment to prevent defects in Printed Circuit Boards (PCBs). This commitment ensures optimal performance across diverse environments and minimizes the occurrence of burnt circuit boards. In PCB fabrication, approximately 96% of the boards meet stringent quality standards, while the remaining 4% require either rework or are deemed as scrap. Collaborating with certified providers ensures adherence to industry-standard quality control and mitigates the potential for costly circuit board damage, guaranteeing a reliable and uninterrupted function.

Types of PCB Testing

• Electrical testing
  Electrical testing checks for proper printed circuit board functioning and component performance through continuity, shorts, opens, and functional tests.
• Environmental testingEnvironmental testing ensures that printed circuit boards can withstand various environmental factors such as temperature fluctuations, humidity changes, vibrations, shock and temperature changes, drops in operating temperature, and chemical exposure.

Conclusion

It’s important to be aware of the dangers of burnt circuit boards. They can be harmful or deadly due to overloading, poor ventilation, short circuits, or component failure. It’s essential to have proper design, assembly, maintenance, and ventilation to avoid potential defects and PCB failure issues. For safety, it’s best to work with certified providers who test boards extensively and prioritize safety. Implementing quality control measures is also crucial to reduce the risk of harm, extend lifespan, and ensure the safety of users.