Delamination in Conformal Coating

Delamination in conformal coating occurs when the coating film loses adhesion and separates from the PCB surface, leaving exposed areas. Preventing delamination is critical to ensure long-term reliability, insulation performance, and protection against environmental stress.

Collage of conformal coating defects on printed circuit boards showing delamination and uneven coverage

What is Delamination in Conformal Coating?

Definition: Delamination is the lifting or peeling of the conformal coating film away from the substrate, creating voids and non-adhered areas.
Impact: This adhesion failure compromises moisture resistance, allows ionic contamination to penetrate, and reduces the mechanical and electrical protection of the PCB.

Causes of Delamination in Conformal Coating

  • Poor surface cleanliness or contamination (oils, dust, flux residues) preventing adhesion.
  • Residual mould-release agents, adhesives, or silicone-based materials on components.
  • Incompatibility between coating chemistry and solder mask or PCB finishes.
  • Improper cure profile or solvent entrapment leading to weak adhesion.
  • Excessive coating thickness generating internal stress and peeling.
  • Moisture absorption at the interface, causing swelling and coating lift.

How to Prevent Conformal Coating Delamination

  • Control cleanliness: Ensure validated cleaning, rinsing, and verification of high-energy surfaces before coating.
  • Optimise process: Apply correct film thickness and use proper drying/cure profiles to avoid stress and solvent entrapment.
  • Use adhesion promoters: Apply primers or adhesion promoters on challenging substrates and finishes.
  • Select compatible materials: Match coatings, solder masks, and surface finishes carefully.
  • Rework locally if needed: Strip and re-apply coating where delamination occurs to restore uniform coverage.

Conformal Coating Defects and Their Importance

Conformal coating is designed to protect printed circuit boards (PCBs) from moisture, corrosion, and electrical leakage. However, defects such as delamination, de-wetting, orange peel, pinholes, bubbles, foam, cracking, and capillary wicking can compromise that protection.

Even small imperfections create pathways for contaminants, lower insulation resistance, and increase the risk of premature failure. These defects may result from incorrect viscosity, poor surface preparation, unsuitable spray settings, or stress during curing.

Understanding and preventing these issues is essential for process control, quality assurance, and long-term reliability.

Training on Conformal Coating Defects & More

SCH provides conformal coating training that goes beyond theory. Our courses teach engineers and operators how to recognise, prevent, and repair defects such as delamination, de-wetting, orange peel, and pinholes. We cover:

  • Failure mechanism recognition.
  • Root cause analysis & troubleshooting.
  • Materials, masking, and application techniques.
  • Process optimisation and inspection methods.

Explore Conformal Coating Training →

Why Choose SCH Services?

Partnering with SCH Services gives you a complete platform for conformal coating, Parylene, and ProShieldESD solutions:

✈️ 25+ Years of Expertise – Trusted by aerospace, medical, defence, automotive, and electronics industries worldwide.

🛠️ End-to-End Support – Guidance on materials, masking, application, inspection, and troubleshooting.

📈 Scalable Solutions – From prototype batches to full-scale production.

🌍 Global Reach – Technical support and supply coverage across Europe, North America, and Asia.

✅ Proven Reliability – Reputation built on quality, consistency, and customer satisfaction.

📞 Call: +44 (0)1226 249019 ✉ Email: sales@schservices.com 💬 Contact Us ›