Conformal Coating Defects Hub

Conformal coating defects can undermine PCB protection, reduce insulation resistance, and cause costly rework or field failures. This hub explains the most common defects, their causes, and how to prevent them—linking to detailed technical articles and inspection guidance.

Infographic showing common conformal coating defects including pinholes, bubbles, orange peel, dewetting, delamination, cracking, corrosion, and capillary wicking around PCB components.

Pinholes, Bubbles & Foam

Gas entrapment during application, drying and curing leaves voids that weaken protection and allow moisture ingress. Common root causes: trapped solvent, high humidity, aggressive spray settings, or insufficient flash.

  • Stabilise viscosity and flash times; avoid over-wet passes.
  • Manage booth RH/temperature and atomisation pressure.
  • Verify drying and curing processes to prevent residual volatiles.

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Orange Peel

A dimpled texture driven by viscosity imbalance, spray atomisation issues, or low surface energy. Affects appearance and can trap contaminants.

  • Tune solvent balance, gun distance, and fan width.
  • Maintain substrate temperature and surface energy.
  • Use pattern boards to validate finish.

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Dewetting

The film pulls back into “islands,” leaving bare areas due to contamination or low surface energy (silicones/oils/surfactants).

  • Improve cleaning; validate ionic/residue levels.
  • Use adhesion promoters/primers where appropriate.
  • Control handling to avoid re-contamination.

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Delamination

Loss of adhesion between coating and substrate from poor prep, moisture ingress, or thermal/CTE stress.

  • Validate surface prep and primer compatibility.
  • Bake/dry substrates to remove absorbed moisture.
  • Qualify cure and thermal cycling against spec.

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Cracking

Fractures form when films are too thick, become brittle, or see high CTE mismatch/thermal shock—creating moisture paths.

  • Keep to spec thickness; manage solvent loss and cure.
  • Choose flexible chemistries where required.
  • Validate thermal profiles and cycling.

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Corrosion & Ionic Contamination

Residual ions plus moisture and bias drive electrochemical migration and dendrites—among the most damaging failure modes.

  • Qualify cleanliness (ROSE/IC/SIR) and tighten process control.
  • Seal edges/keep-outs; avoid entrapment under parts.
  • Select chemistries with proven barrier performance.

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Capillary / Wicking Around Components

Capillary action draws coating into gaps/under parts, breaching keep-outs and creating meniscus lines that impact function.

  • Optimise path/valve height and overlap; reduce over-wet passes.
  • Use fixtures/masking to block capillary routes.
  • Qualify with representative gap geometries.

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Need Help Preventing or Solving Defects?

Whether you’re dealing with repeat coating failures, process variability or new product introduction challenges, SCH can help you eliminate defects at their source—not just react to them.

🛠 Consultancy & Process Optimisation

Backed by more than 30 years of coating experience, our
Consulting Services support you with:

  • Root cause analysis for defects such as delamination, dewetting, capillary wicking and contamination.
  • On-site or remote process audits and troubleshooting.
  • NPI support – helping you set up, validate and stabilise your process from day one.
  • Improved masking, inspection and cleaning methods to reduce rework and scrap.

🎓 Technical Training for Your Team

Prevent defects before they occur with structured, hands-on
Training Courses covering:

  • IPC-A-610 and IPC-CC-830 inspection standards and best practices.
  • Masking, de-masking and inspection techniques to avoid common failures.
  • Process control – thickness, viscosity, cleanliness and curing.
  • Advanced modules on defect identification, root cause analysis and repair.

✔ Why Work With Us?

  • Independent, process-focused support – not tied to one coating brand.
  • Experience across aerospace, automotive, medical and high-reliability manufacturing.
  • Support available on-site, remotely or at our UK/India facilities.

Struggling with a defect right now? Let us help you fix the issue, prevent recurrence and improve long-term reliability.

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Explore Topic Hubs

Conformal Coating Processes Hub
Explore core conformal coating processes—spray, dip, selective robotic, and Parylene. Compare strengths, limits, and selection tips to match volume, cost, and reliability.

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Equipment & Application Methods Hub
Configure application equipment—spray guns & booths, dip systems, and selective valves/robots. Standardise recipes and fixtures to stabilise throughput and yield.

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Masking Hub
Master masking strategies for keep-outs: dots & tapes, reusable boots, custom shapes, and latex sealing. Apply barrier vs shielding correctly for spray, dip, and Parylene.

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Conformal Coating Design Hub
Learn design-for-coating (DfCC / DFM) principles—keep-out zones, component layout, creepage & clearance, masking access, drainage control, and coating thickness planning to eliminate rework and defects before manufacture.

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Inspection & Quality Hub
Build a robust inspection & quality plan: UV coverage checks, thickness verification (AQL, coupons, SPC), adhesion tests, and documentation aligned to IPC/UL.

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Removal & Rework Hub
Choose the right removal & rework method: wet stripping for liquid coatings, precision micro-abrasion for Parylene, and controlled repair workflows that protect pads & leads.

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Parylene Coating Hub
Dive into Parylene coating: dimer grades, deposition parameters, vapour-phase masking, and optical thickness control. See when Parylene outperforms liquid coatings.

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Defects & Failure Mechanisms Hub
Prevent common coating defects—pinholes, dewetting, orange peel, cracking, delamination, corrosion/ionic contamination, and wicking—with root-cause fixes.

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Need Process Support?

Optimising electronics coating methods requires the right combination of materials, equipment, and operator training. Partner with SCH Services for:

Why Choose SCH Services?

Partnering with SCH Services means more than just outsourcing — you gain a complete, integrated platform for
Conformal Coating, Parylene & ProShieldESD Solutions, alongside equipment, materials, and training, all backed by decades of hands-on expertise.

  • ✈️ 25+ Years of Expertise – Specialists in coating technologies trusted worldwide.
  • 🛠️ End-to-End Support – Selection of chemistry/process, masking strategies, inspection, and ProShieldESD integration.
  • 📈 Scalable Solutions – From prototypes to high-volume production.
  • 🌍 Global Reach – Responsive support across Europe, North America, and Asia.
  • ✅ Proven Reliability – Consistent results across services, equipment, and materials.

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