Study of 3D-Printed Dielectric Barrier Windows for Microwave Applications

3D printing technologies offer significant advantages over conventional manufacturing technologies for objects with complicated shapes. This technology provides the potential to easily manufacture barrier windows with a low reflection in a wide frequency band. Several 3D printing methods were examined for this purpose, and the dielectric properties of the various types of materials used for 3D printing were experimentally studied in the frequency range 26–190 GHz. These measurements show that the styrene-butadiene-styrene and polyamide plastics are suitable for broadband low-reflection windows for low-to-medium-power microwave applications. Two barrier windows with optimized surface shapes were printed and tested. Results demonstrate that the studied technique can fabricate windows with a reflection level below −18 dB in the frequency band up to 160 GHz. Studied windows can be used for spectroscopic tasks and other wideband microwave applications.

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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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DESIGN OF A 3D-PRINTED THREE-CLAW ROBOTIC GRIPPER END-EFFECTOR

ASEAN Engineering Journal ◽

10.11113/aej.v11.17865 ◽

2021 ◽

Vol 11 (4) ◽

pp. 70-79

Author(s):

Dino Dominic Forte Ligutan ◽

Argel Alejandro Bandala ◽

Jason Limon Española ◽

Richard Josiah Calayag Tan Ai ◽

Ryan Rhay Ponce Vicerra ◽

...

Keyword(s):

3D Printing ◽

Polylactic Acid ◽

Grip Force ◽

Thermoplastic Polyurethane ◽

Robotic Arm ◽

End Effector ◽

Design Considerations ◽

3D Printed ◽

Materials Used ◽

Metal Work

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.

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3D printing of biofiber-reinforced composites and their mechanical properties: a review

Rapid Prototyping Journal ◽

10.1108/rpj-08-2019-0214 ◽

2020 ◽

Vol 26 (6) ◽

pp. 1113-1129

Author(s):

Lai Jiang ◽

Xiaobo Peng ◽

Daniel Walczyk

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Reinforced Composites ◽

Research Directions ◽

Content Type ◽

Reinforced Composite ◽

3D Printed ◽

Materials Used ◽

Printing Processes ◽

Pure Resin

Purpose This paper aims to summarize the up-to-date research performed on combinations of various biofibers and resin systems used in different three-dimensional (3D) printing technologies, including powder-based, material extrusion, solid-sheet and liquid-based systems. Detailed information about each process, including materials used and process design, are described, with the resultant products’ mechanical properties compared with those of 3D-printed parts produced from pure resin or different material combinations. In most processes introduced in this paper, biofibers are beneficial in improving the mechanical properties of 3D-printed parts and the biodegradability of the parts made using these green materials is also greatly improved. However, research on 3D printing of biofiber-reinforced composites is still far from complete, and there are still many further studies and research areas that could be explored in the future. Design/methodology/approach The paper starts with an overview of the current scenario of the composite manufacturing industry and then the problems of advanced composite materials are pointed out, followed by an introduction of biocomposites. The main body of the paper covers literature reviews of recently emerged 3D printing technologies that were applied to biofiber-reinforced composite materials. This part is classified into subsections based on the form of the starting materials used in the 3D printing process. A comprehensive conclusion is drawn at the end of the paper summarizing the findings by the authors. Findings Most of the biofiber-reinforced 3D-printed products exhibited improved mechanical properties than products printed using pure resin, indicating that biofibers are good replacements for synthetic ones. However, synthetic fibers are far from being completely replaced by biofibers due to several of their disadvantages including higher moisture absorbance, lower thermal stability and mechanical properties. Many studies are being performed to solve these problems, yet there are still some 3D printing technologies in which research concerning biofiber-reinforced composite parts is quite limited. This paper unveils potential research directions that would further develop 3D printing in a sustainable manner. Originality/value This paper is a summary of attempts to use biofibers as reinforcements together with different resin systems as the starting material for 3D printing processes, and most of the currently available 3D printing techniques are included herein. All of these attempts are solutions to some principal problems with current 3D printing processes such as the limit in the variety of materials and the poor mechanical performance of 3D printed parts. Various types of biofibers are involved in these studies. This paper unveils potential research directions that would further widen the use of biofibers in 3D printing in a sustainable manner.

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The Application of 3D-Printing Techniques in the Manufacturing of Cement-Based Construction Products and Experiences Based on the Assessment of Such Products

Buildings ◽

10.3390/buildings10090144 ◽

2020 ◽

Vol 10 (9) ◽

pp. 144

Author(s):

Guillermo Sotorrío Ortega ◽

Javier Alonso Madrid ◽

Nils O. E. Olsson ◽

José Antonio Tenorio Ríos

Keyword(s):

3D Printing ◽

Construction Industry ◽

Material Consumption ◽

Construction Products ◽

International Projects ◽

Substantial Progress ◽

3D Printed ◽

Materials Used ◽

Printing Techniques

The construction industry has embraced digitisation and industrialisation in response to the need to increase its productivity, optimise material consumption and improve workmanship. Additive manufacturing (AM), more widely known as 3D printing, has driven substantial progress in these respects in other industries, and a number of national and international projects have helped to introduce the technique to the construction industry. As with other innovative processes not covered by uniform standards, appropriate assessments and testing methodologies to control the quality of the 3D-printed end products, while not obligatory, are advisable. This article shows that regulation is not an obstacle to the use of an innovative product, such as 3D printing, by proposing quality-control tests and an assessment methodology, in the understanding that standardisation ensures the viability of a technology. The information, including the methods and results, is based on the authors’ experiences in the development of three research projects pertaining to 3D printing. This paper also discusses whether the performance of the materials used in 3D printing could be superior to traditional ones.

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The Effect of Disinfectants Absorption and Medical Decontamination on the Mechanical Performance of 3D-Printed ABS Parts

Polymers ◽

10.3390/polym13234249 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4249

Author(s):

Diana Popescu ◽

Florin Baciu ◽

Catalin Gheorghe Amza ◽

Cosmin Mihai Cotrut ◽

Rodica Marinescu

Keyword(s):

3D Printing ◽

Medical Devices ◽

Mechanical Performance ◽

Acrylonitrile Butadiene Styrene ◽

Extrusion Process ◽

Air Gaps ◽

Safety Issues ◽

Gas Plasma ◽

3D Printed ◽

Butadiene Styrene

Producing parts by 3D printing based on the material extrusion process determines the formation of air gaps within layers even at full infill density, while external pores can appear between adjacent layers making prints permeable. For the 3D-printed medical devices, this open porosity leads to the infiltration of disinfectant solutions and body fluids, which might pose safety issues. In this context, this research purpose is threefold. It investigates which 3D printing parameter settings are able to block or reduce permeation, and it experimentally analyzes if the disinfectants and the medical decontamination procedure degrade the mechanical properties of 3D-printed parts. Then, it studies acetone surface treatment as a solution to avoid disinfectants infiltration. The absorption tests results indicate the necessity of applying post-processing operations for the reusable 3D-printed medical devices as no manufacturing settings can ensure enough protection against fluid intake. However, some parameter settings were proven to enhance the sealing, in this sense the layer thickness being the most important factor. The experimental outcomes also show a decrease in the mechanical performance of 3D-printed ABS (acrylonitrile butadiene styrene) instruments treated by acetone cold vapors and then medical decontaminated (disinfected, cleaned, and sterilized by hydrogen peroxide gas plasma sterilization) in comparison to the control prints. These results should be acknowledged when designing and 3D printing medical instruments.

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Rapid Prototyping Technology for Special Pressure Vessels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.919.222 ◽

2018 ◽

Vol 919 ◽

pp. 222-229

Author(s):

Jiří Šafka ◽

Filip Veselka ◽

Martin Lachman ◽

Michal Ackermann

Keyword(s):

Additive Manufacturing ◽

3D Printing ◽

3D Model ◽

Selective Laser Sintering ◽

Pressure Vessels ◽

Pressure Test ◽

Polypropylene Material ◽

3D Printed ◽

Manufacturing Technologies ◽

Made In

The article deals with the topic of 3D printing of pressure vessels and their testing. The main focus of the research was on a 3D model of the pressure vessel, which was originally designed for a student formula racing car project. The described virtual 3D model was designed with regard to 3D printing. The physical model was manufactured using several additive manufacturing technologies. The first technology was FDM using ULTEM 1010 material. The next technology was SLS (Selective Laser Sintering) using polyamide materials (PA3200GF and PA2220). The last technology was SLA (Stereolithography) using a polypropylene material (Durable). Experimental evaluation of the vessels was carried out by a pressure test, which verified the compactness of the 3D printed parts and their possible porosity. At the end of the article, a comparison of each printed model is made in terms of their final price and weight, together with pressure and thermal resistance.

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The Role of 3D Printing in Medical Applications: A State of the Art

Journal of Healthcare Engineering ◽

10.1155/2019/5340616 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 48

Author(s):

Anna Aimar ◽

Augusto Palermo ◽

Bernardo Innocenti

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Patient Specific ◽

Digital Information ◽

Medical Implants ◽

Medical Field ◽

3D Printed ◽

Pipe Dream ◽

Manufacturing Technologies

Three-dimensional (3D) printing refers to a number of manufacturing technologies that generate a physical model from digital information. Medical 3D printing was once an ambitious pipe dream. However, time and investment made it real. Nowadays, the 3D printing technology represents a big opportunity to help pharmaceutical and medical companies to create more specific drugs, enabling a rapid production of medical implants, and changing the way that doctors and surgeons plan procedures. Patient-specific 3D-printed anatomical models are becoming increasingly useful tools in today’s practice of precision medicine and for personalized treatments. In the future, 3D-printed implantable organs will probably be available, reducing the waiting lists and increasing the number of lives saved. Additive manufacturing for healthcare is still very much a work in progress, but it is already applied in many different ways in medical field that, already reeling under immense pressure with regards to optimal performance and reduced costs, will stand to gain unprecedented benefits from this good-as-gold technology. The goal of this analysis is to demonstrate by a deep research of the 3D-printing applications in medical field the usefulness and drawbacks and how powerful technology it is.

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3D-Printed Drug Delivery Systems: The Effects of Drug Incorporation Methods on Their Release and Antibacterial Efficiency

Materials ◽

10.3390/ma13153364 ◽

2020 ◽

Vol 13 (15) ◽

pp. 3364

Author(s):

Bahaa Shaqour ◽

Inés Reigada ◽

Żaneta Górecka ◽

Emilia Choińska ◽

Bart Verleije ◽

...

Keyword(s):

Drug Delivery ◽

3D Printing ◽

Drug Delivery Systems ◽

Drug Distribution ◽

Delivery Systems ◽

Solvent Casting ◽

Fused Filament Fabrication ◽

3D Printed ◽

Manufacturing Technologies ◽

Drug Incorporation

Additive manufacturing technologies have been widely used in the medical field. More specifically, fused filament fabrication (FFF) 3D-printing technology has been thoroughly investigated to produce drug delivery systems. Recently, few researchers have explored the possibility of directly 3D printing such systems without the need for producing a filament which is usually the feedstock material for the printer. This was possible via direct feeding of a mixture consisting of the carrier polymer and the required drug. However, as this direct feeding approach shows limited homogenizing abilities, it is vital to investigate the effect of the pre-mixing step on the quality of the 3D printed products. Our study investigates the two commonly used mixing approaches—solvent casting and powder mixing. For this purpose, polycaprolactone (PCL) was used as the main polymer under investigation and gentamicin sulfate (GS) was selected as a reference. The produced systems’ efficacy was investigated for bacterial and biofilm prevention. Our data show that the solvent casting approach offers improved drug distribution within the polymeric matrix, as was observed from micro-computed topography and scanning electron microscopy visualization. Moreover, this approach shows a higher drug release rate and thus improved antibacterial efficacy. However, there were no differences among the tested approaches in terms of thermal and mechanical properties.

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Influence of different materials used for 3D printing in miniature speaker enclosure development

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-3188 ◽

2021 ◽

Vol 263 (1) ◽

pp. 5631-5636

Author(s):

Bartlomiej Chojnacki ◽

Jan Pawlik ◽

Tadeusz Kamisinski

Keyword(s):

3D Printing ◽

Manufacturing Industry ◽

Technology Development ◽

Detailed Comparison ◽

Rigid Plastic ◽

Current State ◽

3D Printed ◽

Manufacturing Techniques ◽

Complicated Geometry ◽

Materials Used

Additive manufacturing techniques are commonly used in industry and mechanical prototyping. The past years brought rapid growth in this technology development, also in the speaker cabinets manufacturing industry. We observe numerous DIY projects on the market based on the 3D printed cabinet parts; however, this technology also offers novel options that should be investigated and documented. In the current state of the art, the basic properties and construction aspects for speaker acoustic performance is not provided as the 3d printing technique is usually treated as the tool for other projects' development. This paper will provide a detailed comparison of the most common 3D printing materials used in FDM techno9logy, such as PLA, TPE, PET-G, and others with different mechanical properties. Example enclosure for a loudspeaker of 37 mm diameter will be printed in different shapes and compared for frequency and sensitivity differences. The results will be discussed, investigating the possible use of different than traditional rigid plastic enclosures and new options using complicated geometry shapes possibly to manufacture with 3D printing techniques.

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Potential Development of Sustainable 3D-Printed Meat Analogues: A Review

Sustainability ◽

10.3390/su13020938 ◽

2021 ◽

Vol 13 (2) ◽

pp. 938

Author(s):

Karna Ramachandraiah

Keyword(s):

3D Printing ◽

Ghg Emissions ◽

Food Products ◽

Consumer Acceptance ◽

Meat Production ◽

Vascular Networks ◽

Waste Production ◽

3D Printed ◽

Materials Used

To mitigate the threat of climate change driven by livestock meat production, a multifaceted approach that incorporates dietary changes, innovative product development, advances in technologies, and reductions in food wastes/losses is proposed. The emerging technology of 3D printing (3DP) has been recognized for its unprecedented capacity to fabricate food products with intricate structures and reduced material cost and energy. For sustainable 3DP of meat substitutes, the possible materials discussed are derived from in vitro cell culture, meat byproducts/waste, insects, and plants. These material-based approaches are analyzed from their potential environmental effects, technological viability, and consumer acceptance standpoints. Although skeletal muscles and skin are bioprinted for medical applications, they could be utilized as meat without the additional printing of vascular networks. The impediments to bioprinting of meat are lack of food-safe substrates/materials, cost-effectiveness, and scalability. The sustainability of bioprinting could be enhanced by the utilization of generic/universal components or scaffolds and optimization of cell sourcing and fabrication logistics. Despite the availability of several plants and their byproducts and some start-up ventures attempting to fabricate food products, 3D printing of meat analogues remains a challenge. From various insects, powders, proteins (soluble/insoluble), lipids, and fibers are produced, which—in different combinations and at optimal concentrations—can potentially result in superior meat substitutes. Valuable materials derived from meat byproducts/wastes using low energy methods could reduce waste production and offset some greenhouse gas (GHG) emissions. Apart from printer innovations (speed, precision, and productivity), rational structure of supply chain and optimization of material flow and logistic costs can improve the sustainability of 3D printing. Irrespective of the materials used, perception-related challenges exist for 3D-printed food products. Consumer acceptance could be a significant challenge that could hinder the success of 3D-printed meat analogs.

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