The use of 3D printing for rapid tooling and manufacturing has promised to produce components with complex geometries according to computer designs. Due to the intrinsically limited mechanical properties and functionalities of printed pure polymer parts, there is a critical need to develop printable polymer composites with high performance. 3D printing offers many advantages in the fabrication of composites, including high precision, cost effective and customized geometry. This article gives an overview on 3D printing techniques of polymer composite materials and the properties and performance of 3D printed composite parts as well as their potential applications in the fields of biomedical, electronics and aerospace engineering. Common 3D printing techniques such as fused deposition modeling, selective laser sintering, inkjet 3D printing, stereolithography, and 3D plotting are introduced. The formation methodology and the performance of particle-, fiber- and nanomaterial-reinforced polymer composites are emphasized. Finally, important limitations are identified to motivate the future research of 3D printing.

3D printing of polymer matrix composites: A review and prospective

A comprehensive analysis of literature pertaining to surface texture metrology for metal additive manufacturing has been performed. This review paper structures the results of this analysis into sections that address specific areas of interest: industrial domain; additive manufacturing processes and materials; types of surface investigated; surface measurement technology and surface texture characterisation. Each section reports on how frequently specific techniques, processes or materials have been utilised and discusses how and why they are employed. Based on these results, possible optimisation of methods and reporting is suggested and the areas that may have significant potential for future research are highlighted.

Surface texture metrology for metal additive manufacturing: a review

Meta-materials are structures when their small-scale properties are considered, but behave as materials when their homogenized macroscopic properties are studied. There is an intimate relationship between the design of the small-scale structure and the homogenized properties of such materials. In this article, we studied that relationship for meta-biomaterials that are aimed for biomedical applications, otherwise known as meta-biomaterials. Selective laser melted porous titanium (Ti6Al4V ELI) structures were manufactured based on three different types of repeating unit cells, namely cube, diamond, and truncated cuboctahedron, and with different porosities. The morphological features, static mechanical properties, and fatigue behavior of the porous biomaterials were studied with a focus on their fatigue behavior. It was observed that, in addition to static mechanical properties, the fatigue properties of the porous biomaterials are highly dependent on the type of unit cell as well as on porosity. None of the porous structures based on the cube unit cell failed after 106 loading cycles even when the applied stress reached 80% of their yield strengths. For both other unit cells, higher porosities resulted in shorter fatigue lives for the same level of applied stress. When normalized with respect to their yield stresses, the S-N data points of structures with different porosities very well (R2>0.8) conformed to one single power law specific to the type of the unit cell. For the same level of normalized applied stress, the truncated cuboctahedron unit cell resulted in a longer fatigue life as compared to the diamond unit cell. In a similar comparison, the fatigue lives of the porous structures based on both truncated cuboctahedron and diamond unit cells were longer than that of the porous structures based on the rhombic dodecahedron unit cell (determined in a previous study). The data presented in this study could serve as a basis for design of porous biomaterials as well as for corroboration of relevant analytical and computational models.

Relationship between unit cell type and porosity and the fatigue behavior of selective laser melted meta-biomaterials

This paper first reviews manufacturing technologies for realizing air-filled metal-pipe rectangular waveguides (MPRWGs) and 3-D printing for microwave and millimeter-wave applications. Then, 3-D printed MPRWGs are investigated in detail. Two very different 3-D printing technologies have been considered: low-cost lower-resolution fused deposition modeling for microwave applications and higher-cost high-resolution stereolithography for millimeter-wave applications. Measurements against traceable standards in MPRWGs were performed by the U.K.’s National Physical Laboratory. It was found that the performance of the 3-D printed MPRWGs were comparable with those of standard waveguides. For example, across X-band (8–12 GHz), the dissipative attenuation ranges between 0.2 and 0.6 dB/m, with a worst case return loss of 32 dB; at W-band (75–110 GHz), the dissipative attenuation was 11 dB/m at the band edges, with a worst case return loss of 19 dB. Finally, a high-performance W-band sixth-order inductive iris bandpass filter, having a center frequency of 107.2 GHz and a 6.8-GHz bandwidth, was demonstrated. The measured insertion loss of the complete structure (filter, feed sections, and flanges) was only 0.95 dB at center frequency, giving an unloaded quality factor of 152—clearly demonstrating the potential of this low-cost manufacturing technology, offering the advantages of lightweight rapid prototyping/manufacturing and relatively very low cost when compared with traditional (micro)machining.

3-D Printed Metal-Pipe Rectangular Waveguides

Smart grid communication and information technologies in the perspective of Industry 4.0: Opportunities and challenges

3D printing is an emerging technology in manufacturing. It is the long-term goal of the industry to print complex and fully functional products from cell phones to vehicles. A drawback of many 3D printing technologies is rough surface finish. It is known that metals with high surface roughness severely degrade the propagation of electromagnetic waves. Presented is the first known evaluation of the electromagnetic impact of the typical surface roughness in metal parts produced by electron beam melting. Two Ku-band (12-15 GHz) horn antennas were 3D printed, with different surface roughness, and compared to a standard horn antenna purchased from Pasternack.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/el.2013.1528

Effects of extreme surface roughness on 3D printed horn antenna

Material properties in radio frequency and microwave regimes are limited due to the lack of molecular resonances at these frequencies. Metamaterials are an attractive means to realize a prescribed permittivity or permeability function, but these are often prohibitively lossy due to the use of ine-cient metallic resonators. All-dielectric metamaterials ofier excellent potential to overcome these losses, but they provide a much weaker interaction with an applied wave. Much design freedom can be realized from all-dielectric structures if their dispersion and anisotropy are cleverly engineered. This, however, leads to structures with very complex geometries that cannot be manufactured by conventional techniques. In this work, artiflcially anisotropic metamaterials are designed and then manufactured by 3D printing. The efiective material properties are measured in the lab and agree well with model predictions.

https://www.jpier.org/pierl/pierl34/08.12070311.pdf

3D printing of anisotropic metamaterials

Wireless passive temperature sensors are receiving increasing attention due to the ever-growing need of improving energy efficient and precise monitoring of temperature in high-temperature energy conversion systems, such as gas turbines and coal-based power plants. Unfortunately, the harsh environment, such as high temperature and corrosive atmosphere present in these systems, has significantly limited the reliability and increased the costs of current solutions. Therefore, this paper presents the concept and design of a low cost, passive, and wireless temperature sensor that can withstand high temperature and harsh environments. The temperature sensor was designed following the principle of metamaterials by utilizing closed ring resonators in a dielectric ceramic matrix. The proposed wireless, passive temperature sensor behaves like an $LC$ circuit, which has a temperature-dependent resonance frequency. Full-wave electromagnetic solver Ansys Ansoft HFSS was used to validate the model and evaluate the effect of different geometry and combination of split ring resonator structures on the sensitivity and electrical sizes of the proposed sensor. The results demonstrate the feasibility of the sensor and provide guidance for future fabrication and testing.

Concept and Model of a Metamaterial-Based Passive Wireless Temperature Sensor for Harsh Environment Applications

In this paper, an all-dielectric frequency selective surface (ADFSS) was developed using genetic algorithms and fast Fourier transforms (FFTs) to generate random geometries. This device showed a stop-band fractional bandwidth (FBW) of 54% and a field of view of 16°. The optimized FSS was manufactured by three-dimensional (3-D) printing and the frequency response was measured in the laboratory. This device was also tested in the pass band at a high pulsed microwave power of $\bf{45.26}\;\bf{MW}/\bf{m}^{\bf{2}}$ and no damage was observed. This is the first known demonstration of a 3-D printed ADFSS.

3-D Printed All-Dielectric Frequency Selective Surface With Large Bandwidth and Field of View

In this work, an all-dielectric frequency selective surface was developed for high power microwaves. By avoiding the use of metals, arcing at field concentration points and heating in the conductors was avoided. To do this in a compact form factor while still producing a strong frequency response, we based our design on guided-mode resonance (GMR). To make this approach viable for radio and microwave frequencies, we overcame three major challenges. First, conventional GMR devices have less than 1% fractional bandwidth and we extended this to 16%. Second, conventional GMR devices have a field-of-view less than 1
 °
 and we extended this to over 40
 °
. Third, conventional GMR devices must be composed of hundreds of periods to operate, but our device operated very well with only eight. In this paper, we present our design and experimental results at 1.7 GW/m
 2
.

Jay H. Barton

Papers

Effects of extreme surface roughness on 3D printed horn antenna

3D printing of anisotropic metamaterials

Concept and Model of a Metamaterial-Based Passive Wireless Temperature Sensor for Harsh Environment Applications

3-D Printed All-Dielectric Frequency Selective Surface With Large Bandwidth and Field of View

All-Dielectric Frequency Selective Surface for High Power Microwaves