What conformal coatings are used for automotive electronics? Conformal coatings for automotive...
What is the typical conformal coating thickness? Liquid coatings such as acrylics, urethanes, and silicones commonly target 25-75 µm dry film, while parylene is typically 5-25 µm. Final targets depend on chemistry, environment, and reliability requirements. Verify against applicable standards, the product TDS, and customer or OEM specifications.
Conformal Coating Thickness & Standards Guide
Engineers often need a fast, vendor-neutral reference for typical dry-film thicknesses by chemistry and for the most commonly cited standards in specifications and validation. Use the tables below for planning only, then set final targets from the product Technical Data Sheet (TDS), customer documentation, and OEM requirements.
Important note: The ranges below are planning ranges, not specifications.
Typical dry-film thickness by chemistry
|
Chemistry |
Typical range (µm) |
Notes / when to choose |
|
Acrylic (AR) |
25-75 |
General purpose; easier rework; broad usage. |
|
Urethane (UR) |
25-75 |
Strong chemical and solvent resistance. |
|
Silicone (SR) |
25-100 |
Useful for thermal cycling and vibration; wider thickness window. |
|
Parylene (XY) |
5-25 |
Ultra-uniform thin films for dense assemblies and high-reliability coverage. |
UV curable coatings: These are usually applied between 60 and 130 microns dry thickness. In automotive, the range is between 80 and 110 microns dry thickness.
*Planning ranges only - do not use as a specification. Set final targets per product TDS and customer or OEM requirements.
Standards at a glance
|
Standard |
What it is |
Common uses / notes |
|
IPC-CC-830 |
Current industry qualification |
Most modern specifications cite this. |
|
MIL-I-46058C |
Legacy qualification |
Still referenced historically in some workflows. |
|
NASA low-outgassing |
Materials for space / vacuum |
Validate case by case. |
|
UL 94 flame class |
Material flammability classification |
Program-specific; confirm per module and material. |
|
UL (file-specific) |
Safety, electrical, or flammability recognition |
Confirm the exact UL file and Conditions of Acceptability for the application. |
Measurement and verification tips
- Use a wet-film gauge for liquid coatings and map thickness at edges and tall features; confirm dry-film thickness at critical points.
- Log targets, tolerances, and measurement points for audits, and capture edge or feature coverage photos where feasible.
- Re-verify thickness and coverage after any change to valve type, overlap, path, or other recipe variables.
- Store thickness maps, edge-coverage images, adhesion method and results, and acceptance criteria in the PPAP package.
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FAQ
What is the typical conformal coating thickness?
Most acrylic, urethane, and silicone conformal coatings are typically applied at 25–75 µm dry film thickness, while parylene coatings are usually 5–25 µm. UV-curable coatings commonly range from 60–130 µm. Final targets depend on the application and reliability requirements.
What is the recommended conformal coating thickness for automotive electronics?
Automotive conformal coatings, especially UV-curable materials, are commonly applied between 80–110 µm dry film thickness to support durability and environmental protection requirements.
Why does conformal coating thickness matter?
Proper coating thickness helps protect PCBs from moisture, corrosion, chemicals, thermal shock, and vibration while avoiding issues such as cracking, delamination, or incomplete coverage.
How is conformal coating thickness measured?
Manufacturers commonly use wet-film gauges for liquid coatings and verify dry-film thickness at critical locations, edges, and tall components after curing.
What standards apply to conformal coatings?
Common conformal coating standards include IPC-CC-830, MIL-I-46058C, NASA low-outgassing requirements, and UL flammability or safety standards.
What is IPC-CC-830?
IPC IPC-CC-830 is the current industry qualification standard for conformal coatings and is widely referenced in electronics manufacturing specifications.
What is the difference between parylene and liquid conformal coatings?
Parylene creates ultra-thin, highly uniform vapor-deposited coatings, while liquid coatings like acrylics, silicones, and urethanes are sprayed, dipped, or selectively dispensed at thicker film builds.
Can conformal coating thickness affect reliability?
Yes. Incorrect coating thickness can impact electrical insulation, adhesion, thermal performance, edge coverage, and long-term reliability in harsh environments.
How do manufacturers verify coating quality during production?
Manufacturers often document thickness maps, coverage photos, adhesion test results, and process tolerances for quality audits, PPAP documentation, and OEM validation requirements.
