Delamination in Conformal Coating

Delamination is the loss of adhesion between the conformal coating and the PCB or component surfaces. It often presents as lifting, flaking, or edge peel and can rapidly undermine environmental protection and reliability.

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

What is Delamination in Conformal Coating?

  • Definition: Separation or lift of the coating from the substrate or component leads/bodies.
  • Main issue: Creates moisture paths, reduces insulation resistance, and can propagate to large areas—especially after thermal/humidity exposure.

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Causes of Delamination in Conformal Coating

  • Contamination/low surface energy — oils, silicones, flux residues, mould release.
  • Inadequate surface prep — no adhesion promoter/plasma where required.
  • Moisture in boards/components — outgassing under cure causing lift.
  • Under/over-cure — incomplete crosslinking or embrittlement leading to poor adhesion.
  • CTE mismatch & mechanical stress — thick films across sharp edges, connectors, potting transitions.
  • Incompatible materials — low-adhesion plastics, unprimed metals, silicone-to-acrylic interfaces.
  • Poor film design — heavy single-pass builds that skin before wetting edges.

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How to Prevent Delamination

  • Clean & verify — validated cleaning/rinsing, ionic checks, dyne/contact-angle targets.
  • Adhesion promotion — primers (e.g., A-174), plasma/corona, scuff on metals where appropriate.
  • Moisture control — pre-bake/dry-out PCBs & components before coating; control WIP storage.
  • Right cure profile — follow supplier windows; allow flash-off; avoid over-bake embrittlement.
  • Film design — multiple light passes; edge-break at sharp transitions; avoid puddling.
  • Material compatibility — choose chemistries matched to plastics/metals; use tie-coats if needed.

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Troubleshooting & Diagnosis

  • Adhesion tests — tape pull/cross-hatch on coupons and non-critical areas.
  • Chemical analysis — solvent swab/FTIR for residues; DSC/FTIR for cure state.
  • Environment pre-conditioning — humidity/thermal cycling to reveal marginal adhesion.
  • Microscopy/cross-section — identify interface of failure (substrate vs cohesive).
  • Process audit — primer application, plasma parameters, flash/cure profiles, storage conditions.

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Where Delamination Sits Among Other Defects

Delamination is chiefly an adhesion/cure failure. By contrast, orange peel is flow/level, pinholes/bubbles/foam are air/solvent entrapment, and de-wetting is surface energy/contamination-driven. Targeting the true mechanism prevents repeat failures and costly rework.

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Training on Conformal Coating Defects & More

SCH offers conformal coating training that goes beyond theory—recognising and preventing delamination, de-wetting, orange peel, pinholes, bubbles, foam, and cracking. We cover process analysis, troubleshooting, materials, and application methods.

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Industry Standards We Work To

SCH Services follows international standards across all our coating services, training, equipment supply and materials. Our processes are aligned to the relevant IPC standards, including:

  • IPC-A-610 – Acceptability of Electronic Assemblies
  • IPC-CC-830 – Qualification & Performance of Conformal Coatings
  • IPC-HDBK-830 – Conformal Coating Handbook (guidance and best practice)

For further details on IPC standards, visit:
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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.

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Note: This article provides general technical guidance only. Final design, safety, and compliance decisions must be verified by the product manufacturer and validated against the applicable standards.