Moisture is one of the most persistent threats to electronic reliability. Even small amounts of humidity can corrode components, weaken solder joints, and disrupt critical signals. These failures matter most in industries where performance is non-negotiable. This includes sectors such as aerospace, medical devices, industrial automation, defense systems, and outdoor electronics.
This article explains how moisture affects printed circuit board assemblies and the most effective protection methods. It also explains how to select the right approach and how Star Engineering Inc. supports high-reliability assemblies through specialized processes.
How Humidity Can Affect Your PCB
Moisture impacts electronics through several mechanisms. Understanding them helps determine the level of protection needed.
- Corrosion: Moisture reacts with exposed metal, causing oxidation on copper traces, terminals, and component leads. Over time, this weakens conductivity and produces intermittent failures.
- Short Circuits: Trapped moisture can create conductive paths between adjacent traces. This results in unintended current flow, damaging sensitive components or shutting down the entire assembly.
- Component and Material Degradation: Long-term humidity exposure breaks down plastics, adhesives, and housing materials. Components may swell, warp, or lose mechanical strength.
- Soldering Issues: Moisture-absorbed components can pop, crack, or delaminate during soldering due to rapid moisture expansion (the “popcorn effect”).
- Delamination: Moisture absorbed in laminates of printed circuit board assemblies can separate internal layers. This disrupts performance and compromises structural integrity.
Assembly Options to Protect Electronics From Humidity
Multiple protection methods exist, and each serves different application needs. Here are the most widely used strategies.
- Conformal Coating: A thin protective layer that shields the PCB from moisture, dust, and chemicals.
- Potting / Encapsulation: Complete sealing of the assembly using resin materials, ideal for harsh environments.
- Dry Cabinet Storage: Maintains components at humidity levels low enough to prevent moisture absorption before assembly.
- PCB Baking Before Assembly: Removes absorbed moisture from PCBs and components before soldering.
- Sealed or Waterproof Enclosures: Create a physical barrier that prevents moisture contact with the printed circuit board assembly.
Comparison Table: PCB Moisture-Protection Methods
|
Method |
Purpose | Pros | Cons | Protection Strength | Cost Level |
When It Is Used |
|
Conformal Coating |
Protect PCBs from moisture and contaminants | Lightweight, cost-effective, fast application | Limited protection against deep immersion | Medium | Low–Medium |
Consumer electronics, automotive modules, and indoor industrial systems |
|
Potting / Encapsulation |
Fully seal electronics from moisture and impact | Maximum protection, excellent durability | Hard to rework, adds weight | High | Medium–High |
Defense, aerospace, marine electronics, outdoor controls |
|
Dry Cabinet Storage |
Keep components moisture-free before assembly | Prevents damage during soldering, protects sensitive ICs | Requires ongoing monitoring | Medium | Low |
PCB assembly lines with MSL-rated components |
|
PCB Baking |
Remove absorbed moisture before soldering | Reduces delamination and soldering defects | Over-baking may degrade materials | Medium | Low |
SMT surface mount technology and through-hole PCB assembly |
| Sealed / Waterproof Enclosures | Physically isolate electronics from external moisture | Strong environmental barrier protects the entire assembly | Limited airflow may trap heat | High | Medium |
Outdoor electronics, industrial automation, and marine devices |
How to Choose the Right Moisture-Protection Approach for Your Application
Selecting the ideal method depends on the environment, reliability expectations, and cost considerations. A clear understanding of operational conditions helps determine the level of protection needed.
Key Factors to Consider
- Operating Environment: High-humidity zones, outdoor exposure, medical sterilization, and aerospace conditions require higher protection levels.
- Reliability Requirements: Safety-critical systems often require potting, multiple coatings, or sealed enclosures.
- Budget: Conformal coating is cost-effective, while complete encapsulation is more expensive.
- Maintenance Expectations: Some methods, like potting, limit access to components for repair.
Often, the best approach is to use multiple protection methods for PCB assembly, such as a conformal coating combined with a sealed enclosure.
Also Read:
7 Key Benefits of Automated Electronic PCB Assembly Processes
The Role of EMI Shielding in Ensuring Reliable PCB Assembly in the USA
The Roadblocks in Automotive PCB Assembly and Proven Ways to Resolve Them
How Star Engineering Inc. Helps Protect PCBs from Moisture
Star Engineering Inc. supports businesses across aerospace, commercial, automotive, marine, and medical markets with detailed strategies to reduce moisture-related failures. The team integrates protective processes at multiple stages of production, from component handling to final assembly.
The team with the CB assembly manufacturer delivers assemblies built for reliability. Services include printed circuit board assembly (PCBA), SMT surface-mount technology, through-hole assembly, cable and wire harness production, box build assembly, control panels, and electromechanical solutions.
The team also guides customers in selecting the proper moisture-protection methods based on multiple factors. With application needs and quality as priorities, Star Engineering Inc. supports high-standard manufacturing within the U.S.
Conclusion
Reliable PCB performance over time depends on controlling moisture exposure from the earliest stages of a project. Planning protection strategies such as coatings, encapsulation, controlled storage, or sealed housing during design and assembly is essential. It significantly reduces the risk of corrosion, electrical shorts, and material degradation. Taking a proactive approach helps organizations avoid costly failures and increases confidence in field performance across critical environments.
Star Engineering Inc. helps integrate the right moisture-protection method into a manufacturing workflow. Connect with the team to identify suitable solutions and request a quote for PCB assembly and protection.
