3D-Printed Metasurface Units for Potential Energy Harvesting Applications at the 2.4 GHz Frequency Band

The capability of three-dimensional printed cut-wire metasurfaces to harvest energy in frequencies around 2.4 GHz, is studied in this paper. Cut-wire metasurfaces were constructed using the Fused Filament Fabrication technique. In particular, two metasurfaces, consisting of different materials were produced. The first was constructed using Polylactic Acid as starting material. Then, the printed metasurface was covered with a thin layer of conductive silver paint, in order to achieve good electrical conductivity. The other metasurface was built using commercially available, conductive Electrifi. Both metasurfaces exhibit good energy harvesting behavior, in the frequency band near 2.4 GHz. Their harvesting efficiency is found to be almost three times lower than that obtained for conventional PCB-printed cut-wire metasurfaces. Nevertheless, all of the experimental results presented here strongly corroborate that three-dimensional-printed metasurfaces can be potentially used to harvest energy in the 2.4 GHz frequency band.

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Additive technology applied to the realization of K-band microwave terminations: reproducibility improvement

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078717001404 ◽

2018 ◽

Vol 10 (1) ◽

pp. 3-8

Author(s):

Azar Maalouf ◽

Ronan Gingat ◽

Vincent Laur

Keyword(s):

3D Printing ◽

Frequency Band ◽

Rectangular Waveguide ◽

Three Dimensional ◽

Low Density ◽

Support Material ◽

Additive Technology ◽

3D Printed ◽

K Band

This study examines K-band rectangular waveguide terminations with three-dimensional (3D)-printed loads, and proposes an Asymmetrical Tapered Wedge topology. This geometry shows a good tradeoff between microwave performance and 3D-printing issues (printing directions and support material requirements), thus improving noticeably the reproducibility of the devices. The effect of the density of the 3D-printed load on the reflection parameter of the termination was investigated. Even for a low density, reflection level remained below −27.5 dB between 18 and 26.5 GHz. Reproducibility was demonstrated by the characterization of six loads that were 3D printed under the same conditions. Measurements demonstrate that a maximum reflection parameter level of −33.5 dB can be ensured over the whole frequency band without any post-machining of the 3D-printed devices.

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Comparison of the Accuracy of Three-Dimensional Printed Casts, Digital, and Conventional Casts: An In Vitro Study

European Journal of Dentistry ◽

10.1055/s-0040-1705243 ◽

2020 ◽

Vol 14 (02) ◽

pp. 189-193 ◽

Cited By ~ 2

Author(s):

Passent Aly ◽

Cherif Mohsen

Keyword(s):

Treatment Planning ◽

Computer Aided Design ◽

Three Dimensional ◽

In Vitro Study ◽

Vitro Study ◽

The Other ◽

Intraoral Scanner ◽

Linear Measurements ◽

3D Printed

Abstract Objectives The integration of computer-aided design and manufacturing technologies in diagnosis, treatment planning, and fabrication of prosthetic restoration is changing the way in which prosthodontic treatment is provided to patients. The aim of this study was to compare the accuracy of three-dimensional (3D) printed casts produced from the intraoral scanner using stereolithographic (SLA) 3D printing technique, their digital replicas, and conventional stone casts. Materials and Methods In this in vitro study, a typodont of maxillary and mandibular arches with full dentate ivory teeth was used as a reference cast. The typodont was digitized using Trios 3Shape intraoral scanner to create digital casts. The digital files were converted into 3D printed physical casts using a prototyping machine that utilizes the stereolithography printing technology and photocurable polymer as printing material. Linear measurements (mesiodistal and occlusocervical) and interarch measurements (intercanine and intermolar) were made for digital and prototyped models and were compared with the original stone casts. The reference teeth were canines, first premolars and second premolars in the maxillary and mandibular arches on the right and left sides. The measurements on printed and conventional casts were done by digital caliper while on digital casts; Geomagic Qualify software was used. Statistical Analysis One-way analysis of variance (ANOVA) was used to compare measurements among groups. Results Digital casts showed significantly higher error than the other two groups in all linear and interarch measurements. The mean errors of the digital cast in occlusocervical (OC) and mesiodistal (MD) measurements (0.016 and 0.006, respectively) were higher compared with those in the other two groups (OC, 0.004 and 0.007 and MD, 0.003 and 0.005 [p < 0.0001 and p = 0.02, respectively]). Also, digital mean error in intermolar width (IMW) and intercanine width (ICW) (0.142 and 0.113, respectively) were greater than the other two groups (IMW, 0.019 and 0.008 and ICW, 0.021 and 0.011 [p < 0.0001]). However, the errors were within the acceptable clinical range. Conclusion The 3D printed casts may be considered as a substitute for stone casts with clinically acceptable accuracy that can be used in diagnosis, treatment planning, and fabrication of prosthetic restorations.

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Mechanical Properties of 3D-Printed Acrylonitrile–Butadiene–Styrene TiO2 and ATO Nanocomposites

Polymers ◽

10.3390/polym12071589 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1589 ◽

Cited By ~ 2

Author(s):

Nectarios Vidakis ◽

Markos Petousis ◽

Athena Maniadi ◽

Emmanuel Koudoumas ◽

Marco Liebscher ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Sno2 Nanoparticles ◽

Three Dimensional ◽

Acrylonitrile Butadiene Styrene ◽

International Standards ◽

Fused Filament Fabrication ◽

Melt Mixing ◽

3D Printed ◽

Butadiene Styrene

In order to enhance the mechanical performance of three-dimensional (3D) printed structures fabricated via commercially available fused filament fabrication (FFF) 3D printers, novel nanocomposite filaments were produced herein following a melt mixing process, and further 3D printed and characterized. Titanium Dioxide (TiO2) and Antimony (Sb) doped Tin Oxide (SnO2) nanoparticles (NPs), hereafter denoted as ATO, were selected as fillers for a polymeric acrylonitrile butadiene styrene (ABS) thermoplastic matrix at various weight % (wt%) concentrations. Tensile and flexural test specimens were 3D printed, according to international standards. It was proven that TiO2 filler enhanced the overall tensile strength by 7%, the flexure strength by 12%, and the micro-hardness by 6%, while for the ATO filler, the corresponding values were 9%, 13%, and 6% respectively, compared to unfilled ABS. Atomic force microscopy (AFM) revealed the size of TiO2 (40 ± 10 nm) and ATO (52 ± 11 nm) NPs. Raman spectroscopy was performed for the TiO2 and ATO NPs as well as for the 3D printed nanocomposites to verify the polymer structure and the incorporated TiO2 and ATO nanocrystallites in the polymer matrix. The scope of this work was to fabricate novel nanocomposite filaments using commercially available materials with enhanced overall mechanical properties that industry can benefit from.

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A Multi-Criteria Assessment Strategy for 3D Printed Porous Polyetheretherketone (PEEK) Patient-Specific Implants for Orbital Wall Reconstruction

Journal of Clinical Medicine ◽

10.3390/jcm10163563 ◽

2021 ◽

Vol 10 (16) ◽

pp. 3563

Author(s):

Neha Sharma ◽

Dennis Welker ◽

Soheila Aghlmandi ◽

Michaela Maintz ◽

Hans-Florian Zeilhofer ◽

...

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Patient Specific ◽

Fused Filament Fabrication ◽

Decision Matrix ◽

Maximum Deformation ◽

Patient Specific Implants ◽

High Durability ◽

Orbital Wall ◽

3D Printed

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient’s unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

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A Review on Kinetic Energy Harvesting with Focus on 3D Printed Electromagnetic Vibration Harvesters

Energies ◽

10.3390/en14216961 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6961

Author(s):

Philipp Gawron ◽

Thomas M. Wendt ◽

Lukas Stiglmeier ◽

Nikolai Hangst ◽

Urban B. Himmelsbach

Keyword(s):

Energy Harvesting ◽

Three Dimensional ◽

Research Gaps ◽

Three Dimensional Printing ◽

Energy Harvesters ◽

Electromagnetic Vibration ◽

3D Printed ◽

Iot Devices ◽

Printing Processes ◽

Dimensional Printing

The increasing amount of Internet of Things (IoT) devices and wearables require a reliable energy source. Energy harvesting can power these devices without changing batteries. Three-dimensional printing allows us to manufacture tailored harvesting devices in an easy and fast way. This paper presents the development of hybrid and non-hybrid 3D printed electromagnetic vibration energy harvesters. Various harvesting approaches, their utilised geometry, functional principle, power output and the applied printing processes are shown. The gathered harvesters are analysed, challenges examined and research gaps in the field identified. The advantages and challenges of 3D printing harvesters are discussed. Reported applications and strategies to improve the performance of printed harvesting devices are presented.

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Three-dimensional-printing for microfluidics or the other way around?

International Journal of Bioprinting ◽

10.18063/ijb.v5i2.192 ◽

2019 ◽

Vol 5 (2) ◽

Cited By ~ 1

Author(s):

Yi Zhang

Keyword(s):

3D Printing ◽

Social Impact ◽

Three Dimensional ◽

The Other ◽

Complex Structures ◽

Three Dimensional Printing ◽

Strong Focus ◽

3D Printed ◽

Near Net Shape ◽

Dimensional Printing

As microfluidic devices are designed to tackle more intricate tasks, the architecture of microfluidic devicesbecomes more complex, and more sophisticated fabrication techniques are in demand. Therefore, it is sensible to fabricatemicrofluidic devices by three-dimensional (3D)-printing, which is well-recognized for its unique ability to monolithicallyfabricate complex structures using a near-net-shape additive manufacturing process. Many 3D-printed microfluidic platformshave been demonstrated but can 3D-printed microfluidics meet the demanding requirements in today’s context, and hasmicrofluidics truly benefited from 3D-printing? In contrast to 3D-printed microfluidics, some go the other way around andexploit microfluidics for 3D-printing. Many innovative printing strategies have been made possible with microfluidicsenabled3D-printing, although the limitations are also largely evident. In this perspective article, we take a look at the currentdevelopment in 3D-printed microfluidics and microfluidics-enabled 3D printing with a strong focus on the limitations of thetwo technologies. More importantly, we attempt to identify the innovations required to overcome these limitations and todevelop new high-value applications that would make a scientific and social impact in the future.

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A Multi-Criteria Assessment Strategy for 3d Printed Porous Polyetheretherketone (Peek) Patient-Specific Implants for Orbital Wall Reconstruction

10.20944/preprints202107.0110.v1 ◽

2021 ◽

Author(s):

Neha Sharma ◽

Dennis Welker ◽

Soheila Aghlmandi ◽

Michaela Maintz ◽

Hans-Florian Zeilhofer ◽

...

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Patient Specific ◽

Fused Filament Fabrication ◽

Decision Matrix ◽

Maximum Deformation ◽

Patient Specific Implants ◽

High Durability ◽

Orbital Wall ◽

3D Printed

Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient's unique anatomy. Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

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Three-Dimensional Congenital Heart Models Created With Free Software and a Desktop Printer: Assessment of Accuracy, Technical Aspects, and Clinical Use

World Journal for Pediatric and Congenital Heart Surgery ◽

10.1177/2150135120952072 ◽

2020 ◽

Vol 11 (6) ◽

pp. 797-801

Author(s):

Gregory Perens ◽

Justin Chyu ◽

Kevin McHenry ◽

Takegawa Yoshida ◽

J. Paul Finn

Keyword(s):

Computer Model ◽

Congenital Heart ◽

Three Dimensional ◽

3D Models ◽

Blood Pool ◽

Free Software ◽

Fused Filament Fabrication ◽

3D Printed ◽

Three Dimensional Models ◽

Procedural Planning

Background: Three-dimensional printing is increasingly recognized as a valuable tool for congenital heart disease (CHD) procedural planning and education. Cost and complexity currently limit the more widespread adoption of this technology. We sought to demonstrate the accuracy of 3D printed CHD models created from contrast-enhanced magnetic resonance imaging (MRI) and computed tomography (CT) scans using free software and an inexpensive desktop fused filament fabrication (FFF) printer. Methods: Solid segmentations of the intracardiac blood pool were created with the program ITK-SNAP. Using the computer program Meshmixer, the segmentation model was hollowed to create a 0.8 mm shell with the inner surface representing endocardium. Three-dimensional models were created on an FFF printer. Four arteries and a ventricular septal defect (VSD) were 3D printed and measured for accuracy. Five models were used to assess candidacy for biventricular surgical repair and one to guide an interventional catheterization. Results: All six patients underwent intervention planned with the 3D models. The computer model shell walls all achieved specifications within 0.05 mm of the designated 0.8 mm thickness and the original solid blood pool segmentation fit within the hollowed 3D model. The 3D printed arteries and VSD all measured accurately to within 0.5 mm of their source computer model. Conclusion: Accurate 3D printed models of complex, pediatric CHD may be created from volumetric MRI and CT studies using free online software and printed on an inexpensive desktop printer.

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Three-Dimensional Evaluation on Accuracy of Conventional and Milled Gypsum Models and 3D Printed Photopolymer Models

Materials ◽

10.3390/ma12213499 ◽

2019 ◽

Vol 12 (21) ◽

pp. 3499 ◽

Cited By ~ 7

Author(s):

Jae-Won Choi ◽

Jong-Ju Ahn ◽

Keunbada Son ◽

Jung-Bo Huh

Keyword(s):

Reference Model ◽

Three Dimensional ◽

Color Difference ◽

Physical Models ◽

The Other ◽

3D Analysis ◽

Digital Light Processing ◽

Single Crown ◽

Significant Difference ◽

3D Printed

The aim of this study was to evaluate the accuracy of dental models fabricated by conventional, milling, and three-dimensional (3D) printing methods. A reference model with inlay, single crown, and three-unit fixed dental prostheses (FDP) preparations was prepared. Conventional gypsum models (CON) were manufactured from the conventional method. Digital impressions were obtained by intraoral scanner, which were converted into physical models such as milled gypsum models (MIL), stereolithography (SLA), and digital light processing (DLP) 3D printed photopolymer models (S3P and D3P). Models were extracted as standard triangulated language (STL) data by reference scanner. All STL data were superimposed by 3D analysis software and quantitative and qualitative analysis was performed using root mean square (RMS) values and color difference map. Statistical analyses were performed using the Kruskal–Wallis test and Mann–Whitney U test with Bonferroni’s correction. For full arch, the RMS value of trueness and precision in CON was significantly smaller than in the other groups (p < 0.05/6 = 0.008), and there was no significant difference between S3P and D3P (p > 0.05/6 = 0.008). On the other hand, the RMS value of trueness in CON was significantly smaller than in the other groups for all prepared teeth (p < 0.05/6 = 0.008), and there was no significant difference between MIL and S3P (p > 0.05/6 = 0.008). In conclusion, conventional gypsum models showed better accuracy than digitally milled and 3D printed models.

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Enhanced Mechanical, Thermal and Antimicrobial Properties of Additively Manufactured Polylactic Acid with Optimized Nano Silica Content

Nanomaterials ◽

10.3390/nano11041012 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1012

Author(s):

Nectarios Vidakis ◽

Markos Petousis ◽

Emanuel Velidakis ◽

Nikolaos Mountakis ◽

Lazaros Tzounis ◽

...

Keyword(s):

Polylactic Acid ◽

Three Dimensional ◽

Antibacterial Properties ◽

Antimicrobial Properties ◽

Sio2 Nanoparticles ◽

International Standards ◽

Fused Filament Fabrication ◽

Melt Mixing ◽

Screening Process ◽

3D Printed

The scope of this work was to create, with melt mixing compounding process, novel nanocomposite filaments with enhanced properties that industry can benefit from, using commercially available materials, to enhance the performance of three-dimensional (3D) printed structures fabricated via fused filament fabrication (FFF) process. Silicon Dioxide (SiO2) nanoparticles (NPs) were selected as fillers for a polylactic acid (PLA) thermoplastic matrix at various weight % (wt.%) concentrations, namely, 0.5, 1.0, 2.0 and 4.0 wt.%. Tensile, flexural and impact test specimens were 3D printed and tested according to international standards and their Vickers microhardness was also examined. It was proven that SiO2 filler enhanced the overall strength at concentrations up to 1 wt.%, compared to pure PLA. Atomic force microscopy (AFM) was employed to investigate the produced nanocomposite extruded filaments roughness. Raman spectroscopy was performed for the 3D printed nanocomposites to verify the polymer nanocomposite structure, while thermogravimetric analysis (TGA) revealed the 3D printed samples’ thermal stability. Scanning electron microscopy (SEM) was carried out for the interlayer fusion and fractography morphological characterization of the specimens. Finally, the antibacterial properties of the produced nanocomposites were investigated with a screening process, to evaluate their performance against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).

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