Microwave Coating Thickness Measurement Probe
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coating thickness measurement technologies are limited in accuracy and non-destructive measurement capabilities, especially for polymer coatings on substrates with weak electrical conductivity, such as carbon fibre-reinforced epoxy resin, and are often dependent on the material composition of the substrate and coating.
Innovation Solution
A device using a probe with an internal and external conductor configuration, emitting microwave radiation to measure polymer coating thickness, which calculates phase displacement to determine coating thickness with high accuracy, independent of substrate material composition, and features a compact, mobile design for non-contact measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If eddy current measurement units are used, then non-destructive measurement with sufficient accuracy is achieved, but the substrate must feature really high electrical conductivity which limits applicability to composite materials
Solution Approach 1:
The patent replaces eddy current measurement (electromagnetic induction method) with microwave measurement method. The microwave system transmits electromagnetic waves through the coating and measures the reflected signal, eliminating the requirement for high electrical conductivity of the substrate. This substitution enables measurement on composite materials like carbon fiber reinforced plastics while maintaining measurement accuracy.
Solution Approach 2:
The patent changes the measurement parameter from electrical conductivity-based eddy current to dielectric constant-based microwave reflection. By using microwaves with frequencies typically between 1 GHz and 100 GHz, the measurement becomes dependent on the dielectric properties of the coating rather than the electrical conductivity of the substrate, thus enabling versatile application across different material types.
2Device complexity
If purely mechanical measurement units are used, then simple construction is achieved, but non-destructive measurement and measurement accuracy are inherently limited
Solution Approach 1:
The patent replaces mechanical penetration measurement with microwave-based non-contact measurement. The mechanical system physically contacts and penetrates the coating, while the microwave system uses electromagnetic wave reflection, achieving both non-destructive measurement and higher accuracy through phase displacement analysis of the reflected microwave signal.
Solution Approach 2:
The patent introduces microwave radiation as an intermediary between the measurement device and the coating. Instead of direct mechanical contact, the microwave signal acts as a mediator that interacts with the coating's dielectric properties, allowing non-destructive measurement with high precision through signal processing and phase analysis.
3Measurement precision
If conventional microwave measurement is used on metallic substrates, then measurement is achieved, but the dielectric constant enters the result with square root factor reducing accuracy
Solution Approach 1:
The patent changes the substrate type from highly conductive metals to composite materials with weak electrical conductivity. This parameter change in substrate electrical properties eliminates the problematic square root dependence on dielectric constant and enables accurate measurement on modern composite aircraft structures while improving adaptability to contemporary manufacturing materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate measurement of polymer coating thickness between 50 μm and 800 μm on substrates with varying electrical conductivity, providing high measurement accuracy and independence from substrate material composition, with direct digital readout in millimeters or microns.
Implementation Method 1
a device for the measurement of coating thicknesses by means of microwave radiation
Implementation Method 2
the measurement is based on the evaluation of the phase displacement that ensues with the passage of microwaves through the medium and their subsequent reflection from the base material
Implementation Method 3
A device using a probe with an internal and external conductor configuration, emitting microwave radiation to measure polymer coating thickness
Data Source
AI summary
A device for measurement of a thickness of a coating applied to a substrate includes a transmitter/receiver module configured to transmit and receive microwave radiation; a computing unit; and a probe having a flange and an inner and an outer conductor, wherein the outer conductor coaxially surrounds the inner conductor, and wherein the inner conductor includes at least one thickened section.