Conformal Coating Inspection: Standards & Methods

Conformal coating inspection is a vital stage in ensuring that coatings are correctly applied, free from defects, and meet the quality standards needed for long-term PCB reliability. Industry standards such as IPC-A-610 and IPC-CC-830 define what is acceptable and provide a framework for consistent quality.

Infographic explaining conformal coating inspection standards, acceptance criteria, and inspection equipment for PCB reliability

Why Inspection Matters

Inspection verifies that conformal coatings protect the circuit board as intended, detecting defects or coverage issues that could compromise performance or reliability.

Key Standards

  • IPC-A-610 – Provides acceptance criteria for electronic assemblies, including coating coverage, curing, adhesion, and defect-free finishes.
    • Class 1 (General Electronics): Acceptable for products where the main requirement is function, such as consumer devices.
    • Class 2 (Dedicated Service Electronics): Higher performance and extended life expected, such as industrial or automotive electronics.
    • Class 3 (High-Performance/Harsh Environment): Highest level of reliability for mission-critical or life-support electronics, such as aerospace, defence, and medical.
  • IPC-CC-830 – Governs material qualification and performance requirements, replacing the older Mil-I-46058C standard.
  • Internal & Customer Standards – Often adapted from IPC guidelines, especially for high-reliability Class 2 and Class 3 electronics.

Common Acceptance Requirements

  • Coating fully cured, uniform, and homogeneous
  • Applied only where required, without overspray
  • No pinholes, bubbles, cracks, or dewetting exposing circuitry
  • No foreign material reducing electrical clearance
  • Coating not wicking into connectors or mating surfaces
  • Transparent or lightly tinted, without discolouration

Inspection Equipment

UV (Ultraviolet) Inspection Booths

  • Purpose: Most conformal coatings include a UV tracer, making coverage visible under blacklight.
  • Pros: Fast, simple, highlights coverage and missed areas clearly.
  • Cons: Cannot reveal all defects (e.g. cracks, orange peel, delamination) and inspection quality depends on operator skill.

Find out more about UV Inspection Equipment >

Microscopes and Digital Imaging

  • Purpose: Stereo microscopes, digital microscopes, and high-resolution cameras magnify defects such as pinholes, bubbles, or wicking.
  • Pros: Reveals fine details not visible to the naked eye; images can be stored for quality records or customer reporting.
  • Cons: Time-consuming; requires trained operators; limited coverage per inspection cycle.

Coating Thickness Measurement

  • Purpose: Confirms that the coating is applied within specified limits (e.g. 25–50µm for liquid, 10–20µm for Parylene).
  • Techniques: Eddy-current gauges, optical interference meters, or destructive cut-back methods.
  • Pros: Provides quantitative, traceable data; supports process control.
  • Cons: Some methods are expensive; destructive techniques are not suitable for all assemblies.

Find out more about Coating Thickness Equipment >

Illumination & Contrast Tools

  • Purpose: White light, angled lighting, or contrasting backdrops can highlight defects such as ripples, fisheyes, and orange peel.
  • Pros: Simple, low-cost, enhances defect visibility beyond UV alone.
  • Cons: Operator dependent; subjective results.

Summary

Conformal coating inspection underpins the quality and reliability of coated PCBs. By applying IPC standards and using the right mix of UV inspection, microscopes, thickness gauges, and illumination tools, manufacturers can detect and prevent defects early, ensuring reliable performance in demanding environments.

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 by aerospace, medical, defence, automotive, and electronics industries worldwide.
  • 🛠️ End-to-End Support – Guidance on coating selection, Parylene grades, masking strategies, application methods, inspection, and ProShieldESD integration.
  • 📈 Scalable Solutions – From small prototype batches to full-scale, high-volume production, SCH delivers flexible capacity that grows with your needs.
  • 🌍 Global Reach – Responsive technical support and supply coverage across Europe, North America, and Asia.
  • ✅ Proven Reliability – A strong reputation built on quality, consistency, and customer satisfaction across services, equipment, and materials.

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