Orange Peel in Conformal Coating

Orange peel in conformal coating is a surface defect where the cured coating develops a textured, uneven finish that looks like the skin of an orange. This defect can reduce coating thickness and compromise PCB protection.

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Orange peel effect in conformal coating on PCB surface under UV inspection

What is Orange Peel in Conformal Coating?

  • Definition: An uneven, textured surface that appears dull and looks like the skin of an orange.
  • Main Issue: The conformal coating layer may be too thin in places to provide adequate protection.

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Causes of Orange Peel in Conformal Coating

  • Improper spray application – coating applied too far from the PCB dries before it can level.
  • Incorrect thickness – insufficient coating deposited to self-level.
  • Viscosity too high – coating cannot flow out smoothly.
  • Poor cure profile – inadequate flash-off before heat cure or oven misprofiled.

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How to Prevent Orange Peel in Conformal Coating

  • Adjust viscosity – reduce viscosity so the coating can level out.
  • Optimise spray setup – reduce air pressure and set correct spray distance per material guidelines.
  • Apply sufficient coating – especially when using aerosols, ensure enough passes for a level finish.
  • Allow flash-off – extend solvent evaporation time before heat cure.
  • Check cure profile – re-profile the oven using the supplier’s recommended settings.

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Troubleshooting & Diagnosis

  • Pattern boards/UV inspection — verify finish uniformity, meniscus, and edge definition.
  • Viscosity & solids checks — monitor solvent loss; restore target windows.
  • Spray gun setup validation — document head type, spray gun distance, fan width, and pressures.
  • Pass strategy — switch to multiple lighter passes with proper flash.
  • Cure profile review — ensure progressive ramping so the film levels before skinning.

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Where Orange Peel Sits Among Other Defects

Orange peel is primarily a flow/level problem (viscosity, film build, setup). By contrast, pinholes/bubbles/foam stem from entrapped air or premature skinning; de-wetting flags contamination/low surface energy; delamination points to adhesion/cure issues. Addressing the right mechanism reduces rework and protects long-term reliability.

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Training on Conformal Coating Defects & More

SCH offers conformal coating training that goes beyond theory—recognising and preventing orange peel, pinholes, bubbles, foam, de-wetting, delamination, and cracking. We cover process analysis, troubleshooting, materials selection, NPI 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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Conformal Coating Processes Hub
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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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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, de-wetting, orange peel, cracking, delamination, corrosion/ionic contamination, and wicking—with root-cause fixes.

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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.

  • ✈️ 25+ Years of Expertise – Specialists in coating technologies trusted worldwide.
  • 🛠️ End-to-End Support – Guidance on coating selection, masking, inspection, and ProShieldESD integration.
  • 📈 Scalable Solutions – From prototype to high-volume production.
  • 🌍 Global Reach – Support across Europe, North America, and Asia.
  • ✅ Proven Reliability – Built on quality, consistency, and customer satisfaction.

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