Terahertz Sensor for Non-Contact Thickness and Quality Measurement of Automobile Paints of Varying Complexity
Year: 2014
Type: article
Abstract: In this paper, we propose to use terahertz pulsed imaging (TPI) as a novel tool to measure the thickness and quality of up to four layers of car paint on both metallic and non-metallic substrates. Using a rigorous one-dimensional electromagnetic model for terahertz propagation in a multi-layered medium combined with a numerical fitting method, the refractive index, extinction coefficient, and thickness of individual paint layers were determined. This proposed method was shown to be able to resolve coating layers down to a thickness of 18 μm and was validated for both single- and multi-layer automobile paint samples. Results of the terahertz measurements were benchmarked against other techniques that are currently used for non-destructive testing during car manufacture: ultrasound and eddy current measurements, as well as two reference techniques, X-ray microcomputed tomography and surface profilometry. Good consistency was found between the techniques. Compared to conventional techniques, TPI has the advantage that it is a non-contact method and that it is able to spatially resolve the thickness uniformity distribution information by two-dimensional mapping.
Authors: Ke Su, Yao-Chun Shen, J. Axel Zeitler
Institutions: University of Cambridge, University of Liverpool
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,670
OpenAlex ID: W2018498210