Conformal Coating Thickness Measurement Methods
Accurate conformal coating thickness measurement on printed circuit boards (PCBs) is a vital part of modern process control. Without reliable thickness verification, coatings may fail to provide the necessary protection against moisture, dust, and chemicals, leading to costly failures in the field.
Both internal process controls and international quality standards (such as IPC and ISO) require consistent, traceable coating thickness levels. This ensures long-term performance, compliance with customer requirements, and reduced risk of rework or rejection.
To achieve this, there are two main categories of conformal coating thickness measurement used across the industry:
✅ Wet film measurement – Performed during application while the coating is still wet. This provides an in-process check, helping operators maintain quality control and avoid over-application.
✅ Dry film measurement – Conducted after the coating has dried or cured enough to prevent damage. This method is highly accurate, often non-destructive, and provides traceable records for audits and customer specifications.
By combining wet film and dry film measurement techniques, manufacturers can build a robust quality assurance process that ensures coatings are applied within specification, delivering consistent and reliable PCB protection.
Dry Film Conformal Coating Thickness Measurement
Dry film measurements are performed after the coating process, once the conformal coating is stable enough to handle. This approach is preferred for accuracy and repeatability.
Positector Conformal Coating Non-Contact System
SCH offers the Positector 6000, a proven non-destructive thickness measurement system using eddy current technology.
✅ Accuracy to ±1 μm for thin films of 25–50 μm
✅ Instant, repeatable measurements with a simple probe placement
✅ Easy-to-use handheld gauge with flying probe system
For best results, test coupons should be coated at the same time as PCBs. These provide a permanent physical record of thickness performance and act as a reliable quality reference for both spray and dip coating processes.
📄 Positector coating thickness measurement system PDF
Wet Film Conformal Coating Thickness Measurement
Wet film thickness measurement is an in-process control method, allowing operators to check coating levels while the conformal coating is still wet.
This method is especially useful when:
-
Coatings are difficult to measure in the dry state (e.g. destructive methods would be required)
-
Over-application must be avoided due to cost or performance issues
The process uses wet film gauges:
✅ Applied directly to the wet coating surface
✅ The gauge teeth indicate the wet thickness
✅ Dry film thickness is then calculated using the coating’s resin solids content
SCH supplies wet film gauges in convenient packs of 200 for production use.
Why Thickness Measurement Matters
-
Ensures coatings meet IPC and customer specifications
-
Prevents costly over-application of materials
-
Provides traceable quality records using test coupons
-
Improves consistency in both spray and dip coating processes
-
Enables compliance with international standards and audits
Conformal Coating Thickness Measurement – FAQs
Why is conformal coating thickness measurement important?
Measuring coating thickness ensures PCBs meet IPC and customer specifications, prevents over-application, and improves product reliability.
What methods are used for conformal coating thickness measurement?
There are two main methods: wet film measurement during application and dry film measurement after curing. Each has advantages depending on the coating and process.
What is the Positector 6000 system?
The Positector 6000 is a non-destructive, eddy current-based system for dry film thickness measurement. It delivers fast, accurate, and repeatable results down to ±1 μm.
When should wet film gauges be used?
Wet film gauges are best for in-process checks, especially when dry film measurement is difficult or destructive. They help avoid costly over-application.
How accurate are test coupons for coating thickness measurement?
Test coupons coated alongside PCBs provide a permanent, traceable record of coating performance and are an ideal way to verify thickness during production.
Does SCH Technologies use these methods in-house?
Yes. SCH uses both wet film gauges and the Positector system within our own coating services to maintain high-quality, repeatable results.
Downloads
📄 Positector coating thickness measurement system
Useful Links
🔗 [Spray Booths]
🔗 [Drying Cabinets]
🔗 [Coating Removal]
Why Choose SCH Services for Conformal Coating and Parylene?
Partnering with SCH Services means more than just outsourcing — you gain a complete, integrated conformal coating and Parylene solution backed by decades of hands-on expertise.
✅ 25+ Years of Expertise – Specialists in conformal coating and Parylene processing, trusted by aerospace, medical, defence, and electronics industries worldwide.
✅ End-to-End Support – Guidance on coating selection, Parylene grades, masking strategies, application methods, and inspection to ensure compliance and reliability.
✅ 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 in conformal coating and Parylene services.
📞 Call: +44 (0)1226 249019
✉ Email: sales@schservices.com
💬 [Contact Us]
