Conformal layer of PCB

What is a pcb conformal coating?

Conformal layer is a protective transparent layer that is applied to the surface of the printed circuit board (PCB). This effectively protects electronic components and traces from moisture, dust, and chemical corrosion. The layer according to the shape of the PCB – therefore the name – forms a “invisible and thin and flexible armor.

Why do you need a conformal layer?

1. Prevent short circuits & leaks that are induced by moisture

In a high humidity environment, the condensation of humidity in the PCB can cause current leakage or electrolytic corrosion, which causes damage to the system or failure.

2. Dust and contaminant resistant

In an industrial environment, automotive, or kitchen, dust, oil, and metal particles can accumulate on the board, creating a conductive path.

3. Increase resistance to salt spray & chemicals

Sea electronics and offshore exposed to salt spray, which can quickly oxidize solder joints and copper traces

4. Increase mechanical stability

Some coatings (for example, silicon) elastic, reduce the voltage on the solder connection from the vibration.

5. Meet industrial standards

Sectors such as automotive, medical, and military often need compliance with IPC, AEC-Q100, or MIL-STD-L-Repair consequences are the main processes.

When is PCB conformal coating needed?

Not every PCB requires a conformal layer, but it becomes important when the board faces difficult conditions. Think of moisture, dust, chemicals, or large temperature swings – this can cause corrosion, short circuits, or signal problems. Electronics in cars, airplanes, industrial engines, or external lighting often require this extra layer of protection.

Miniature PCB or high density also benefit from the conformal layer. Small space between components increases the likelihood of shorts or solder problems. A thin protective layer helps keep the circuit safe and reliable.

Boards that often experience heating, cooling, or vibrations that often also benefit. The layer helps absorb stress, reduce cracks and extend the life of the board. In short, if your PCB works in a challenging environment, the conformal layer is usually an intelligent choice. The following is what application tables require PCB conformal coating.

Application	Environmental challenges	The recommended type of coating
ECU Automotive	Humidity, vibration, changes in temperature	Polyurethane (PU)
Aerospace Electronics	Extreme temperature swing, humidity	Silicon (SR)
Industrial machinery	Chemicals, dust, mechanical stress	Acrylic (AR)
Outdoor lighting	Exposure to UV, rain, dust	Parylene coating or UV-CURED
PCB is high density	Miniature components, tight distances	Conformal coating layer (thin or acrylic pu)

The risk of passing the conformal layer

→ The initial failure of the product: Damaged in a warranty, increasing after -sales costs

→ Customer Complaints & Brand Damage: Bad reliability damage reputation

→ Risk of Mass Withdrawal: May require full batch re -work

→ Certification failed: May not pass the IP, CE, or UL test

The main thing is: Save the cost of coating can be worth ten times more for improvement

General misunderstanding

Myth 1: Only external devices that need to be coated

→ Moist climate, kitchen oil, and industrial dust are also a threat.

Myth 2: Pot can replace the conformal layer

→ Pot is for structural protection – higher costs, more difficult to fix. Lighter and more flexible layer.

Myth 3: Protection of Guarantee

→ uneven applications, bubbles, or areas that have been missed reduce effectiveness. Process control is very important.

How to choose the right layer?

Type	Pro	Counter	Application
Acrylic	Easy to apply & repair, low costs	Moderate chemical resistance	General industry, consumers
Polyurethane	Good chemical & humidity resistance	Difficult to fix	Automotive, outdoors
Silicone	High temperature resistance, flexible	Higher costs	LED high-temp lighting, LED
UV-Cable	Fast healing, the right scope	Requires UV lamps, a shadow area that is difficult to coated	Precision module, selective layer

Conclusion

Conformal PCB layers are not optional – it is important to increase product reliability, age, and market competitiveness.

Recommendation: Evaluating the needs of coating at the beginning of the design. Reserve of the guard zone and protect the test point to avoid re -work.

This entry was posted on Friday, September 5, 2025 at 18:33 and was submitted under the best PCB, BestTPCB, FAQ, PCB News, PCBA. You can follow any response to this entry through RSS 2.0 bait. You can jump to the end and leave a response. Pinging is currently not permitted.