Conformal Coating Thickness Targets

Setting the correct conformal coating thickness targets is one of the easiest ways to improve long-term product reliability. Too thin and you lose moisture and contamination protection. Too thick and you risk bubbles, cracking, meniscus build-up and rework.

This guide explains how to define realistic thickness windows by chemistry and function so engineers and coating suppliers are aligned.

• Barrier protection: Thickness strongly influences resistance to moisture and ionic contamination.
• Dielectric strength: More film generally raises breakdown voltage up to a limit.
• Mechanical behaviour: Over-thick coatings can crack on edges, ribs and tall components.
• Process yield: Excessive thickness increases bubbles, voids and cure time issues.
• Cost efficiency: Extra material, masking and cycle time increase production cost.

The goal is a controlled thickness window that balances protection, manufacturability and cost.

Every datasheet is different, but most conformal coating thickness targets fall into predictable bands. Use the following as a design starting point, then refine with your coating partner:

Chemistry	Dry film range (µm)	Notes
Parylene (N, C, etc.)	5–25 µm	Ultra-uniform, pinhole-free vapour-deposited films.
Acrylic	25–75 µm	General-purpose; easy to apply and rework.
Urethane	50–100 µm	High chemical resistance; needs thicker film for full barrier performance.
Silicone	75–200 µm	Flexible; excellent for condensation and thermal cycling.
Thick-film hybrids	> 200 µm	Between coating and potting; careful drainage required.

Always confirm ranges with the product datasheet and coating supplier.

Nano-coatings (hydrophobic / oleophobic fluoropolymer treatments) are extremely thin surface films, typically 0.1–2 µm. They are not considered conformal coatings and do not provide the moisture barrier, insulation or environmental protection of acrylics, silicones, urethanes or Parylene.

They are ideal for water repellency, anti-wetting behaviour and improved cleanability, but should not be used where electrical, corrosion or condensation protection is required.

More information: SCH Nano-Coatings Overview

Choose thickness based on what you are protecting against:

• Benign environments: Use lower-end ranges.
• Industrial environments: Use mid-range values.
• Condensing or harsh environments: Use upper-end values (with drainage design).
• Mixed technologies: Align Parylene and liquid thicknesses to avoid clearance issues.

Avoid vague notes like “apply thin even coat”. Specify:

• A clear thickness window in µm.
• The thickness measurement method (eddy-current, optical, coupons).
• Whether thickness applies only to flat coupon areas or also complex geometry.
• Any known exceptions where reduced thickness is acceptable.
• Relevant standards or customer specifications.

• Add drain paths at the base of tall component clusters.
• Break up dams formed by connectors or shields.
• Avoid sharp edges where cracking occurs under thick films.
• Consider selective coating for high-thickness chemistries.
• Flag unavoidable pools as accepted variations in drawings.

• Review layout together to identify risk areas.
• Run process trials to build real data.
• Agree a nominal range and tolerance.
• Define SPC or AQL checks for ongoing control.

Once agreed, thickness becomes a shared design–process contract.

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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Note: This article provides general design guidance for conformal coating and Parylene. It does not replace product-specific standards, OEM requirements or safety approvals. Always validate final layouts and electrical spacings against the relevant IEC/IPC standards, customer specifications and safety agency rules for your application.