Additive manufacturing (AM) is a rapidly growing industry whose utility has been expanded beyond metals and to other materials such as polymers, ceramics, and concrete, to name a few. However, advancement in the development of inspection techniques, particularly in-line nondestructive testing (NDT) methods, lags significantly. Most of the research in developing such methods has focused on metal-based AM. This paper presents a high-resolution dielectric-loaded waveguide probe for detecting small flaws in 3D printed polymeric structures. The electromagnetic (EM) design and optimization of such a probe are discussed in this paper. The probe design is based on concentrating the interrogating electric field of an open-ended waveguide in a thin dielectric slab insert. This results in obtaining a higher spatial resolution than when using only the open-ended waveguide. Subsequently, such a probe was fabricated at a frequency of 74 GHz (V-band (50-75 GHz)) and was used to raster scan a Thermoplastic Polyurethane (TPU) sample, with very small surface flaws, to generate a near-field image. The resulting image confirms the usefulness of this technique as a potentially viable method for in-line monitoring of polymeric AM structures.
(1) Ngo, T.D., Kashani, A., Imbalzano, G., Nguyen, K. T. Q., and Hui, D., 2018, “Additive manufacturing (3D printing): A review of materials, methods, applications and challenges”, Composites Part B, 143, pp 172-196.
(2) Wickramasinghe, S., Do, T., and Tran, P., 2020, “FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments”, Polymers, 12, 1529, pp 1-42.
(3) Everton, S.K., Hirsch, M., Stravroulakis, P., Leach, R.K., and Clare, A.T.,2016, “Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing”, Materials and Design, 95, pp 431-445.
(4) Tabib-Azar,M.,2001,“Microwave Microscopy and its Applications”,AIP Conference Proceedings557,pp400-413.
(5) Rosner, B. T., and Van der Weide, D. W., 2002, “High-Frequency Near-Field Microscopy”, Review of Scientific Instruments, 73 (7), pp 2505-2523.
(6) Chu, z., Zheng, L., and Lai, K., 2020, “Microwave Microscopy and Its Applications”, Annual Reviews of Materials Research, 50, pp 105-130.
(7) Zoughi, R., and Kharkovsky, S., 2008, “Microwave and Millimetre Wave Sensors for Crack Detection,” Fatigue & Fracture of engineering Materials & Structures, 31, pp 695–713.
(8) Ghasr, M., Kharkovsky, S., Zoughi, R., and Austin, R.,2005, “Comparison of Near-Field Millimeter-Wave Sensors for Detecting Corrosion Precursor Pitting under Paint,” IEEE Transactions on Instrumentation and Measurement, 54 (4), pp 1497–1504.
(9) Zoughi, R.,2000, Microwave non-destructive testing and evaluation, Amsterdam, The Netherlands: Kluwer.
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