Journal ArticleDOI
Noncontact Thickness Measurement of Metal Films Using Eddy-Current Sensors Immune to Distance Variation
Hongbo Wang,Wei Li,Zhihua Feng +2 more
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TLDR
The results of this paper revealed that online thickness measurement systems could be developed for various advanced industrial applications.Abstract:
A simple method for measuring the thickness of metal films based on eddy-current sensors (ECSs) immune to distance variation is proposed. The slope of the lift-off curve (LOC) in the RL impedance plane is a good feature for characterizing target thickness independent of lift-off distance variation. A simple equivalent model was built to deal with the ECS problem, and the essential relationship between the slope of LOC (SLOC) and target properties was obtained. Full finite element analysis was conducted to analyze the relationship between SLOC feature and target thickness, and the results matched the modeling results very well. A sensor coil probe was then manufactured and used to measure the thickness of copper films with high performance, and the capability of this technique for online noncontact thickness measurement was verified. The basic characteristics and performances of this thickness measurement technique were tested and discussed. The SLOC feature for thickness measurement had significant advantages, such as simplicity, reliability, immunity to the lift-off effect (most important), high speed, simple signal processing, and negligible design limitation of the sensor probe. The results of this paper revealed that online thickness measurement systems could be developed for various advanced industrial applications.read more
Citations
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Journal ArticleDOI
Challenges in improving the performance of eddy current testing: Review:
TL;DR: Eddy current testing plays an important role in numerous industries, particularly in material coating, nuclear and oil and gas as mentioned in this paper. However, the eddy current testing technique still needs to focus on t...
Journal ArticleDOI
Thickness measurement using liftoff point of intersection in pulsed eddy current responses for elimination of liftoff effect
TL;DR: In this paper, the authors investigated and interpreted the behaviors of liftoff point of intersection (LOI) points due to a plate with varying conductivity and thickness by means of simulations and experiments.
Journal ArticleDOI
Pulsed eddy current thickness measurement using phase features immune to liftoff effect
TL;DR: The phase of spectral PEC response from a Hall sensor are proposed to serve as robust features for thickness evaluation, and the presented novel features are immune to liftoff effect.
Journal ArticleDOI
Design and Characterization of Tri-Axis Soft Inductive Tactile Sensors
TL;DR: In this paper, a soft inductive tactile sensor (SITS) is presented for dexterous robotic manipulations by providing shear force, slip, or contact angle information, which is a new type of tactile sensor that measures inductance variations caused by eddy-current effect.
Journal ArticleDOI
Robust and high-performance soft inductive tactile sensors based on the Eddy-current effect
Hongbo Wang,Hongbo Wang,Jun Wai Kow,N. Raske,GN De Boer,Mazdak Ghajari,Robert Hewson,Ali Alazmani,Peter Culmer +8 more
TL;DR: In this article, a Soft Inductive Tactile Sensor (SITS) is proposed to measure the inductance variation caused by changes in AC magnetic field coupling between coils and conductive films.
References
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Journal ArticleDOI
Analytical Solutions to Eddy-Current Probe-Coil Problems
C. V. Dodd,W. E. Deeds +1 more
TL;DR: In this paper, the axially symmetric eddy-current problems are solved in two configurations of wide applicability. But the solutions are in the form of integrals of first-order Bessel functions giving the vector potential, from which other electromagnetic quantities of interest can be obtained.
Journal ArticleDOI
Non-Destructive Techniques Based on Eddy Current Testing
TL;DR: An overview of the fundamentals and main variables of eddy current testing is included, and the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems are described.
Journal ArticleDOI
Thickness measurement of non-magnetic plates using multi-frequency eddy current sensors
Wuliang Yin,Anthony Peyton +1 more
TL;DR: In this article, a robust feature in multi-frequency eddy current (MEC) testing has been found that can be directly linked to the thickness of the plate under test, which is shown mathematically that the peak frequency of the imaginary part of the inductance change when an air-cored coil is placed next to a non-magnetic metallic plate is inversely proportional to the surface thickness of a given material.
Journal ArticleDOI
Improvement in calculation of the self- and mutual inductance of thin-wall solenoids and disk coils
Slobodan Babic,Cevdet Akyel +1 more
TL;DR: In this paper, a combined analytic and numeric approach was proposed to calculate the self-inductance of thin-wall solenoids and disk coils for superconducting magnetic energy storage (SMES) problems.
Journal ArticleDOI
Thickness and conductivity of metallic layers from pulsed eddy‐current measurements
TL;DR: In this article, the lift-off effect was used to determine the thickness of nonconducting coatings on metal substrates. But, these instruments are not suitable for determining the thickness on conducting substrates, as they are not suited for determining thickness of metal layers on conducting substrate.