Improving Reproducibility of Eddy-Current-Based Coating Thickness Estimation with Printed Circuit Board-Based...

Area of Science:

• Materials Science
• Electrical Engineering
• Non-Destructive Testing

Background:

• Accurate metallic coating thickness determination is crucial for industrial quality control.
• Eddy current testing is a non-destructive method for evaluating coating thickness.
• Conventional wire-wound coils suffer from manufacturing tolerances affecting measurement accuracy.

Purpose of the Study:

• To derive and validate an analytical mutual impedance model for a multi-layer PCB pancake coil.
• To compare the performance of PCB coils against wire-wound coils for coating thickness estimation.
• To assess the reproducibility and accuracy of PCB coil systems.

Main Methods:

• Derivation of an analytical mutual impedance model for a differential multi-layer PCB pancake coil.
• Validation of the model against established literature models.
• Experimental measurements using two-layer and eight-layer PCB differential coil systems.
• Comparison of parameter estimation performance between PCB and wire-wound coils.

Main Results:

• The derived PCB coil model shows high forward modeling accuracy and parameter estimation performance.
• PCB differential coil systems exhibit significantly better reproducibility than wire-wound coils.
• A two-layer PCB coil achieved close agreement with reference values without extra calibration, maintaining high sensitivity.

Conclusions:

• Multi-layer PCB pancake coils provide a more accurate and reproducible method for non-destructive metallic coating thickness measurement.
• PCB coils overcome the limitations of wire-wound coils due to tighter fabrication tolerances.
• The developed model and PCB coil systems enhance industrial quality control for metallic coatings.