UV (UVA) Inspection: Coverage & Edge Definition

Conformal coating inspection often relies on ultraviolet (UV-A) light sources to assess coverage quickly and accurately. Because most conformal coatings include a UV tracer dye, they fluoresce under blacklight. This makes it easy to see where the coating is present, missing, or applied incorrectly.

Infographic showing UV (UVA) inspection for conformal coating, highlighting coverage assessment, edge definition, and limitations.

Why Use UV Inspection?

UV inspection gives operators a fast, non-destructive way to confirm conformal coating coverage. When viewed under UV light, the coating fluoresces, and therefore:

  • The operator can instantly see whether the board surface is fully covered.
  • Edge definition around masked areas becomes clear and consistent.
  • Overspray or leakage stands out immediately.

As a result, UV inspection has become a production standard because it delivers instant feedback with low equipment costs.

Find out more about our conformal coating UV inspection booths.

Coverage Assessment

  • Uniform Fluorescence: Even glowing surfaces prove that the coating is complete and reliable.
  • Missed Areas: Dark spots immediately reveal voids or skips, which often lead to pinholes and bubbles.
  • Shadowing: Components sometimes block spray paths. Consequently, these shaded areas can remain uncoated and may encourage capillary wicking or incomplete protection.

Edge Definition

  • Clean Edges: Sharp, clear boundaries show that masking was applied and removed correctly.
  • Bleed or Overspray: Coating spreading into keep-out zones signals process issues. In many cases, this relates to dewetting or orange peel.
  • Feathered Edges: Blurred boundaries suggest poor masking or coating control. Over time, this can cause delamination.

A PCB being inspected inside a IB101 UV Inspection Booth under UVA light

Limitations of UV Inspection

Although UV inspection is excellent for coverage and edge clarity, it cannot show every defect. For example, it does not reliably reveal:

  • Pinholes and bubbles hidden within the film
  • Delamination or poor adhesion beneath the surface
  • Orange peel, fisheyes, or micro-cracking

Therefore, production lines often combine UV inspection with white light checks, magnification, or thickness measurement to achieve complete quality assurance.

Summary

UV (UVA) inspection acts as a fast and effective first-line tool for evaluating conformal coating coverage and edge definition. It immediately highlights missed areas, overspray, and masking quality.

However, because UV inspection cannot reveal every defect, it must work alongside other inspection methods to fully comply with IPC-A-610 acceptance criteria and prevent issues such as pinholes, dewetting, and orange peel.

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.

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