scholarly journals Rapid Prototyping of Personalized Articular Orthoses by Lamination of Composite Fibers upon 3D-Printed Molds

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 939
Author(s):  
Juan Manuel Munoz-Guijosa ◽  
Rodrigo Zapata Martínez ◽  
Adrián Martínez Cendrero ◽  
Andrés Díaz Lantada

Advances in additive manufacturing technologies and composite materials are starting to be combined into synergic procedures that may impact the biomedical field by helping to achieve personalized and high-performance solutions for low-resource settings. In this article, we illustrate the benefits of 3D-printed rapid molds, upon which composite fibers can be laminated in a direct and resource-efficient way, for the personalized development of articular splints. The rapid mold concept presented in this work allows for a flexible lamination and curing process, even compatible with autoclaves. We demonstrate the procedure by completely developing an autoclave-cured carbon fiber–epoxy composite ankle immobilizing, supporting, or protecting splint. These medical devices may support patients in their recovery of articular injuries and for promoting a more personalized medical care employing high-performance materials, whose mechanical response is analyzed and compared to that of commercial devices. In fact, this personalization is fundamental for enhanced ergonomics, comfort during rehabilitation, and overall aesthetics. The proposed design and manufacturing strategies may support the low-cost and user-centered development of a wide set of biomedical devices and help to delocalize the supply chain for involving local populations in the development of medical technology.

2020 ◽  
Vol 12 (21) ◽  
pp. 9063
Author(s):  
Alejandro Bonnet de León ◽  
Cecile Meier ◽  
Jose Luis Saorin

This paper describes a process to adapt tools in an artistic ceramic workshop in which custom molds are created using low-cost digital manufacturing technologies. The digitalization of busts by a 3D scanner and their transformation into 3D printed molds is a simple technique that only requires basic digital tools. These molds were used in the artistic ceramic workshop of the Psychopedagogical Center of the Order of San Juan de Dios in Tenerife, where the authors worked with people with intellectual disabilities to make ceramic pieces. These people, in most cases, do not have the necessary skills for detail modeling; however, with the help of digital manufacturing technologies, they can produce molds of their own faces and create personalized figures autonomously. In this way, they increase their self-esteem and autonomy and discover new possibilities for making products; as a result, they feel fulfilled and confirm that they can be part of the creation process. To obtain an evaluation of the activity, a qualitative study was carried out, and observation data were collected. The attitudes of the users were compared with observations made during a similar activity without using molds or technologies. It was observed that the attitude of the participants significantly improved when they obtained more satisfactory results with the use of molds.


Author(s):  
Ali N. Sarvestani ◽  
Nekoda van de Werken ◽  
Pouria Khanbolouki ◽  
Mehran Tehrani

Additively manufactured polymers can be reinforced with high-performance reinforcements such as carbon fibers. Printed thermoplastics with embedded continuous carbon fibers are up to two orders of magnitude stronger and stiffer than high-grade 3D printed polymers. In this work, the mechanical response of such 3D printed carbon fiber specimens is evaluated. While the precursor carbon fiber reinforced filaments achieve a stiffness of 50GPa and strength 700MPa, mechanical properties of their printed parts are highly affected by printed carbon fiber curvatures. In this work, the structure of 3D printed parts was examined, and some design rules for 3D printing with continuous carbon fibers are suggested. Moreover, failure mechanisms in these samples are discussed and correlated to the micro-structure of the composites and the carbon fiber configuration.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiaming Ma ◽  
Zhi Li ◽  
Zi-Long Zhao ◽  
Yi Min Xie

Purpose Furniture plays a significant role in daily life. Advanced computational and manufacturing technologies provide new opportunities to create novel, high-performance and customized furniture. This paper aims to enhance furniture design and production by developing a new workflow in which computer graphics, topology optimization and advanced manufacturing are integrated to achieve innovative outcomes. Design/methodology/approach Workflow development is conducted by exploring state-of-the-art computational and manufacturing technologies to improve furniture design and production. Structural design and fabrication using the workflow are implemented. Findings An efficient transdisciplinary workflow is developed, in which computer graphics, topology optimization and advanced manufacturing are combined. The workflow consists of the initial design, the optimization of the initial design, the postprocessing of the optimized results and the manufacturing and surface treatment of the physical prototypes. Novel chairs and tables, including flat pack designs, are produced using this workflow. The design and fabrication processes are simple, efficient and low-cost. Both additive manufacturing and subtractive manufacturing are used. Practical implications The research outcomes are directly applicable to the creation of novel furniture, as well as many other structures and devices. Originality/value A new workflow is developed by taking advantage of the latest topology optimization methods and advanced manufacturing techniques for furniture design and fabrication. Several pieces of innovative furniture are designed and fabricated as examples of the presented workflow.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Fernández Álvarez ◽  
Darren A. Cadman ◽  
Athanasios Goulas ◽  
M. E. de Cos Gómez ◽  
Daniel S. Engstrøm ◽  
...  

AbstractConventional planar frequency selective surfaces (FSSs) are characterized in the far-field region and they are sensitive to the incidence angle of impinging waves. In this paper, a spherical dome FSS is presented, aiming to provide improved angular stable bandpass filtering performance as compared to its planar counterpart when the FSS is placed in the near-field region of an antenna source. A comparison between the conformal FSS and a finite planar FSS is presented through simulations at the frequency range between 26 to 40 GHz in order to demonstrate the advantages of utilizing the conformal FSS in the near-field. The conformal FSS is 3D printed and copper electroplated, which leads to a low-cost and lightweight bandpass filter array. Placing it in the near-field region of a primary antenna can be used as radomes to realize compact high-performance mm-wave systems. The comparison between simulated and measured conformal FSS results is in good agreement. The challenges that arise when designing, manufacturing, and measuring this type of structure are reported and guidelines to overcome these are presented.


2016 ◽  
Vol 2 (2) ◽  
pp. 40
Author(s):  
Concepción Río Vega ◽  
Ana Ribas Sangüesa

ResumenLa fachada autoportante de ladrillo cara vista es el resultado de una profunda reflexión sobre las diferentes soluciones de fachada de ladrillo que se han utilizado a lo largo de la historia. Ha sido promovida por Hispalyt en estrecha colaboración con el Departamento Técnico de Geohidrol S.A., empresa líder en la investigación, fabricación y comercialización de sistemas para cerramientos de fábrica. Cuando se analizan las diferentes soluciones de las fachadas de ladrillo, bajo la óptica de los requisitos del Código Técnico de la Edificación, la fachada autoportante 'STRUCTURA' se manifiesta como la solución óptima por su simplicidad, sus elevadas prestaciones y el bajo coste en recursos auxiliares. La fachada autoportante 'STRUCTURA' se caracteriza porque la hoja exterior del cerramiento se construye totalmente separada del edificio, gravitando sobre sí misma, lo cual permite la disposición de una cámara de aire (ventilada o no) con aislamiento térmico continuo. De esta forma se elimina el puente térmico en el encuentro con los frentes de pilares y forjados, mejorando notablemente el rendimiento higrotérmico del edificio con el fin de cumplir el Documento Básico de Ahorro de Energía (DB HE), cuyos requisitos en la nueva versión aprobada en Septiembre de 2013 han experimentado un sustancial incremento respecto de los contenidos en la versión anterior. Desde el punto de vista de la respuesta mecánica, la fachada autoportante se fundamenta en el aprovechamiento del potencial que tienen los muros de ladrillo cuando se utilizan como soportes de sí mismos. A diferencia de las soluciones convencionales o de las que requieren elementos auxiliares de sostén dispuestos planta a planta, con la solución 'STRUCTURA' el muro de ladrillo se analiza como un elemento activo en el comportamiento estructural, de manera que su propio peso contribuye beneficiosamente en la resistencia frente a las acciones horizontales.AbstractThe self-supporting face brick façade is the result of a profound reflection on the different solutions for the brick façades that have been used throughout history. It has been promoted by Hispalyt in close collaboration with the Technical Department of Geohidrol S.A., leader company in the research, manufacture and marketing of systems for masonry closings. When analyzing different solutions of face brick façade, under the perspective of the technical building code requirements, the self-supporting façade 'STRUCTURA' appears as the optimal solution for its simplicity, high performance and low cost in auxiliary resources. The self-supporting façade 'STRUCTURA' is characterised by the outer leaf of the enclosure being built fully separately from the building, supported on itself, and thus enabling the provision of an air chamber (ventilated or not) with continuous thermal insulation. In this manner thermal bridges on the fronts of pillars and floors are eliminated, noticeably improving the hygrothermal performance of the building in order to comply with the technical building code basic document for energy saving (DB HE), whose requirements in the new version approved in September 2013 have substantially increased with respect to the requirements of the previous version. From the point of view of the mechanical response, the self-supporting façade is based on exploiting the potential that brick walls have when used as a load-bearing structural element themselves. Unlike conventional solutions or those that require additional support devices arranged floor-to-floor, with the 'STRUCTURA' solution the brick wall is analyzed as an active element in the structural behaviour, so that its own weight contributes beneficially to the resistance against horizontal actions.


2019 ◽  
Author(s):  
Alperen Guver ◽  
Nafetalai Fifita ◽  
Peker Milas ◽  
Michael Straker ◽  
Michael Guy ◽  
...  

AbstractA low-cost Scanning Electrochemical Microscope (SECM) was built with a 0.6 pA current measurement capability potentiostat and submicron resolution motorized stage, using open source software and hardware tools. The high performance potentiostat with a Python graphical user interface was built based on an open source project. Arduino boards, stepper motors, a manual XY micromanipulator stage, 3D printed couplers and gears were used in building the motorized stage. An open source motor control software was used for moving the motorized stage with high precision. An inverted microscope was utilized for viewing a standard microelectrode while scanning. The setup was tested in the formation of a map of electrochemical signals from an array of pores on a parafilm membrane. As the setup will be used in future biosensing experiments, DNA hybridization detection experiments were also performed with the setup.


Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 610
Author(s):  
Raúl V. Haro-Baez ◽  
Jorge A. Ruiz-Cruz ◽  
Juan Córcoles ◽  
José R. Montejo-Garai ◽  
Jesús M. Rebollar

This paper presents a novel design of an eight-port directional coupler with a very compact structure and simple manufacturing, working in the Ku frequency band. One of the main goals of the design was to ease the manufacturing with a simple structure: the coupler consisted of four rectangular waveguide input ports, four rectangular waveguide output ports, and a central coupling region with only H-plane variation. A prototype was fabricated using additive manufacturing, with a combination of 3D printing and silver coating metallization. The obtained performance showed a theoretical bandwidth of 6.6% with 20 dB return loss for the input/output ports. Good agreement between simulations and measurements was obtained, validating the proposed coupler as a good trade-off for low cost 3D printing, compactness, and high performance for systems requiring a high number of ports as in phase arrays or Butler matrices.


2021 ◽  
Author(s):  
Paola Ginestra ◽  
Leonardo Riva ◽  
Elisabetta Ceretti ◽  
David Lobo ◽  
Sophie Mountcastle ◽  
...  

Powder bed fusion techniques enable the production of customized and complex devices that meet the requirements of the end user and target application. The medical industry relies on these additive manufacturing technologies for the advantages that these methods offer to accurately fit the patients’ needs. Besides the recent improvements, the production process of 3D printed bespoke implants still requires optimization to achieve the optimal properties that can mimic both the chemical and mechanical characteristics of the anatomical region of interest. In particular, the surface properties of an implant device are crucial to obtain a strong interface and connection with the physiological environment. The layer by layer manufacturing processes lead to the production of complex and high-performance substrates but always require surface treatments during post-processing to improve the implant interaction with the natural tissues and promote a shorter assimilation for the fast recovery and wellness of the patient. Although the surface finishing can be tailored to enhance cells adhesion, proliferation and differentiation in contact with a metal implant, the same surface properties can have a different outcome when dealing with bacteria. This work aims to provide a preliminary analysis on how different post-processing techniques have distinct effects on cells and bacteria colonization of 3D printed titanium implants. The goal of the paper is to highlight the importance of the identification of an optimized methodology for the surface treatment of Ti6Al4V samples produced by Selective Laser Melting (SLM) that improves the implant antimicrobial properties and promotes the osseointegration in a long-term period.


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