Epoxy Conformal Coating | Hard, Chemical-Resistant PCBA Protection

Epoxy conformal coating provides a hard, durable, and chemically resistant protective layer for printed circuit board assemblies operating in harsh industrial, automotive, and aerospace environments. Unlike softer acrylic or silicone coatings, epoxy forms a rigid, high-adhesion barrier that withstands repeated exposure to fuels, solvents, hydraulic fluids, and mechanical abrasion.

What Is Epoxy Conformal Coating?

Epoxy conformal coating (also known as conformal coating epoxy) is a two-part (resin and hardener) polymer system that cures to form a tough, cross-linked thermoset film. Unlike thermoplastics (acrylic, some silicones), epoxy coatings cannot be re-melted or re-dissolved once cured — providing exceptional long-term stability and chemical resistance.

At Tengxinjie, we provide professional epoxy coating PCB services using automated selective spray systems, manual spray, or dip-coating methods. Our epoxy PCBA protection process is fully compliant with IPC-CC-830 and RoHS standards, making it suitable for mission-critical applications where durability and chemical resistance are paramount.

Epoxy Conformal Coating

Key Benefits of Epoxy Conformal Coating

🛡️ Exceptional Hardness & Abrasion Resistance

Epoxy conformal coating cures to a rigid, high-durometer film that resists scratching, gouging, and mechanical wear during assembly, handling, and field operation. This makes it ideal for boards subject to physical contact or vibration.

🧪 Superior Chemical & Solvent Resistance

Conformal coating epoxy withstands prolonged exposure to fuels, oils, hydraulic fluids, dilute acids, bases, and industrial cleaning solvents — significantly outperforming acrylic and many silicone formulations.

💧 Excellent Moisture & Humidity Protection

Epoxy coating PCB provides a highly effective barrier against moisture ingress, preventing corrosion, dendritic growth, and electrical leakage in humid or condensing environments.

🔗 High Adhesion to Multiple Substrates

Epoxy systems exhibit exceptional adhesion to FR-4, ceramic, metal, and many plastic substrates without requiring specialized primers. This ensures complete, long-lasting protection even on difficult surfaces.

How Does Epoxy Compare to Other Conformal Coatings?

Epoxy vs. Acrylic

Epoxy offers much higher chemical resistance, hardness, and abrasion resistance. Acrylic is easier to rework and recoat but is softer and less resistant to solvents. Epoxy conformal coating is preferred for industrial and automotive applications; acrylic is common for consumer electronics and field-repairable assemblies.

Epoxy vs. Silicone

Silicone provides superior thermal stability and flexibility across a wide temperature range (-40°C to +200°C) but has lower chemical resistance and tear strength. Epoxy coating PCB is harder, more chemically resistant, and adheres more strongly, but it is less flexible and may crack under extreme thermal cycling.

Epoxy vs. Urethane

Both offer excellent chemical resistance. Urethane is generally more flexible and impact-resistant; epoxy is harder and provides superior adhesion. Conformal coating epoxy is often specified for static, high-wear environments, while urethane may be chosen for flexible assemblies or those subject to vibration.

Epoxy vs. Parylene

Parylene is ultra-thin, pinhole-free, and biocompatible — ideal for medical and aerospace. Epoxy PCBA protection is thicker, harder, and significantly less expensive. Choose epoxy for industrial, automotive, and general-purpose harsh environment electronics where ultra-thin coverage is not required.

Epoxy Conformal Coating Technical Specifications

Parameter	Epoxy Coating Capability
Coating Type	Two-part epoxy (solvent-based or solvent-free options available)
Application Methods	Automated selective spray, manual spray, dip coating, brush
Typical Thickness	25 – 130 µm (1 – 5 mils) — thicker coatings available for additional protection
Curing Method	Thermal cure (typically 15-60 minutes at 100-150°C) or room temperature (24-48 hours)
Temperature Range	-40°C to +130°C (intermittent exposure to higher temperatures possible with specialized formulations)
Dielectric Strength	1,500 – 3,000 V/mil (depending on thickness and formulation)
Hardness (Shore D)	70 – 85 (fully cured)
Water Absorption	< 0.2% (24-hour immersion)
Compliance	IPC-CC-830, RoHS, UL (specific grades upon request)
Color	Clear, amber, or opaque (custom colors available for volume orders)

Primary Applications for Epoxy Conformal Coating

🏭 Industrial Controls

PLC modules, motor drives, power supplies, and factory automation equipment exposed to dust, humidity, oils, and industrial chemicals. Epoxy conformal coating provides long-term protection in manufacturing environments.

🚗 Automotive Electronics

Engine control units (ECUs), transmission controllers, battery management systems, and under-hood sensors subject to fuels, oils, temperature extremes, and vibration.

✈️ Aerospace & Defense

Avionics, navigation systems, missile guidance, and ground support equipment requiring proven chemical resistance and mechanical durability.

⚡ Power Electronics

Inverters, converters, and high-voltage power supplies operating in dusty, humid, or chemically contaminated environments.

🔋 Energy Storage

Battery protection circuits, BMS boards, and fuel cell controllers requiring moisture and corrosion resistance.

🛠️ Heavy Equipment & Off-Highway

Construction, agricultural, and mining equipment electronics exposed to extreme dust, moisture, and chemical contamination.

Why Choose Tengxinjie for Epoxy Conformal Coating?

✅ Precision Application Equipment

Our automated selective spray systems apply epoxy coating PCB with ±1mm accuracy, reducing overspray, minimizing masking requirements, and ensuring consistent thickness across every board.

🔬 Full Process Control & Inspection

Every coated board undergoes thickness measurement, UV/visual inspection, and adhesion testing to verify coating quality. We provide full traceability documentation for each batch.

🧪 Material Selection & Engineering Support

Not sure which epoxy formulation is right for your operating environment? Our technical team provides material recommendations, mask design, and DFM feedback to optimize coating performance and cost.

🌍 Global Compliance & Documentation

All processes comply with IPC-CC-830 and RoHS. We support automotive (IATF 16949), industrial, and aerospace requirements with complete CoC, FAI, and test reports.

Ready to Protect Your PCBA with Epoxy Conformal Coating?

Upload your files and coating specifications. Our engineering team will review your design, recommend the optimal epoxy system, and provide a detailed quote within 12-24 hours.

Request a Quote →

✔ NDA Available ✔ ISO 9001:2015 ✔ IPC-CC-830 Compliant ✔ Fast Turnaround ✔ Automotive & Industrial Support

Frequently Asked Questions (FAQs)

1. What is epoxy conformal coating?

Epoxy conformal coating is a two-part polymer system (resin and hardener) that cures to form a hard, thermoset protective layer on printed circuit boards. It provides exceptional chemical resistance, abrasion resistance, and adhesion to substrates like FR-4, ceramic, and metal.

2. How does conformal coating epoxy differ from acrylic or silicone?

Conformal coating epoxy is significantly harder and more chemical-resistant than acrylic or standard silicones. Acrylics are flexible and reworkable but softer and less solvent-resistant. Silicones offer superior thermal stability but lower chemical resistance and tear strength. Choose epoxy for harsh industrial or automotive environments where chemical exposure and physical wear are concerns.

3. Is epoxy coating PCB removable for rework?

Epoxy coating PCB is more difficult to remove than acrylic or silicone due to its cross-linked thermoset structure. Removal typically requires specialized chemical strippers, microblasting, or thermal decomposition. For designs anticipating rework, we recommend selective coating to keep test points and connectors uncoated, or considering acrylic as an alternative.

4. What is the typical curing process for epoxy conformal coating?

Epoxy conformal coating can be cured at room temperature (24-48 hours) or accelerated with heat (15-60 minutes at 100-150°C). Thermal curing is strongly recommended for production volumes, as it achieves full cross-linking and maximum chemical resistance much faster than ambient cure.

5. What thickness should epoxy coating be applied?

Typical thickness for epoxy PCBA protection ranges from 25 to 130 microns (1 to 5 mils). Thinner coatings (25-50µm) provide adequate moisture and chemical resistance; thicker coatings (75-130µm) offer additional mechanical protection against abrasion and impact. Our process ensures uniform thickness across your boards.

6. What standards apply to epoxy conformal coating?

Our epoxy conformal coating processes comply with IPC-CC-830 (the industry standard for conformal coating qualification), RoHS, and select UL grades. We can also support customer-specific requirements for automotive (IATF 16949), industrial, and aerospace applications with full documentation.

7. Can epoxy conformal coating be applied selectively?

Yes. Using automated selective spray equipment, we apply epoxy coating PCB only to designated areas, leaving connectors, test points, and other keep-out zones uncoated. We also offer precision masking for complex assemblies or low-volume selective coating requirements.

8. Is epoxy conformal coating suitable for flexible PCBs?

Epoxy coatings are rigid and may crack on flexible circuits that undergo repeated bending. For flex or rigid-flex PCBAs requiring flexibility, silicone or specialized flexible urethane coatings are typically better choices. For static flex applications or boards with minimal flexing, epoxy can be used successfully.

9. What is the temperature rating of epoxy conformal coating?

Standard epoxy conformal coating grades are rated for continuous operation from -40°C to +130°C. Specialized high-temperature epoxy formulations can withstand intermittent exposure up to 150-180°C. For applications exceeding 150°C continuous, silicone or Parylene HT may be more appropriate.

10. How do I get a quote for epoxy conformal coating?

To receive a quote for epoxy conformal coating, please upload your Gerber files, assembly drawings, or sample boards. Indicate any keep-out areas requiring masking, specify thickness requirements (if any), and describe your operating environment. Our engineering team will review your requirements and provide a detailed quotation within 12-24 hours.