Conformal Coated Power Supplies: Advantages

Conformal coating is a protective layer applied to the PCB assemblies of power supplies to improve durability and performance in industrial environments. It helps shield sensitive components from moisture, dust, and other airborne contaminants. But there’s still confusion about what it actually accomplishes—and what expectations are unrealistic.

This article focuses on acrylic coatings—the most common choice in industrial-grade conformal coated power supplies, medical grade conformal coated power supplies, and DIN rail conformal coated power supplies. While most manufacturers do not publish an exact thickness specification, it’s generally understood they follow industry norms.

What Conformal Coated Power Supplies Actually Protects Against

1. Humidity and moisture—Acrylic helps limit corrosion and leakage currents caused by damp air or occasional condensation.
   
   

2. Dust and particles—Prevents buildup on conductive surfaces, reducing the chance of shorts and arcing. It also reduces the likelihood of current paths forming between conductors in high-voltage or polluted environments.
   
   

3. Chemical vapors and contaminants—Offers some defense against corrosive gasses that might otherwise degrade board materials.
   
   

4. Thermal cycling—Acts as a buffer during minor expansion/contraction of components due to changing temperatures.
   

Why Acrylic?

Acrylic is widely used because it strikes a practical balance between protection, ease of application, inspection, and serviceability. It dries quickly, adheres well, and is cost-effective.

According to IPC-A-610 standards, the recommended coating thickness for acrylic ranges from 30 to 130 micrometers. Specialty Coating Systems (SCS) suggests that 50–75 µm is the sweet spot for most industrial applications. 

Common Misconceptions: What Conformal Coated Power Supplies Don't Achieve

1. Overheating problems—Conformal coating doesn’t dissipate heat. It may reduce thermal stress during rapid temperature changes, but it won’t fix undersized heatsinks or poor ventilation.
   
   

2. Waterproofing solution—Coated supplies are more resistant to condensation and splashes—not submersion. You still need proper IP-rated enclosures for wet environments.
   
   

3. Mechanical protection—The coating won’t protect against vibration, shock, or physical impact. That’s still a job for the enclosure and mounting system.
   
   

Final Thoughts

Acrylic conformal coated power supplies are an effective and proven way to improve the environmental resilience of a power supply. It’s a standard feature in many Delta DRF models and other conformal coated power supplies. But it’s not a magic fix. It complements—but doesn’t replace—good system design, thermal management, and mechanical protection.

If you’re deploying DIN rail power supplies in demanding applications, confirm whether conformal coating is present, what type is used, and how it fits into your broader reliability strategy.