scholarly journals Additive Manufacturing Applications on Flexible Actuators for Active Orthoses and Medical Devices

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Michele Gabrio Antonelli ◽  
Pierluigi Beomonte Zobel ◽  
Francesco Durante ◽  
Terenziano Raparelli

This paper describes the results of research projects developed at the University of L’Aquila by the research group of the authors in the field of biomedical engineering, which have seen an important use of additive manufacturing technologies in the prototyping step and, in some cases, also for the realization of preindustrialization prototypes. For these projects, commercial 3D printers and technologies such as fused deposition modelling (FDM) were used; the most commonly used polymers in these technologies are acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). The research projects concern the development of innovative actuators, such as pneumatic muscles and soft pneumatic actuators (SPAs), the development of active orthoses, such as a lower limb orthosis and, finally, the development of a variable-stiffness grasper to be used in natural orifice transluminal endoscopic surgery (NOTES). The main aspects of these research projects are described in the paper, highlighting the technologies used such as the finite element analysis and additive manufacturing.

2019 ◽  
Vol 821 ◽  
pp. 137-143 ◽  
Author(s):  
Pavan Kumar Gurrala ◽  
Brijesh Tripathi

In the current technological evolution, additive manufacturing is taking a lead role in manufacturing of components for both prototyping as well as finished products. Metallization of the polymer parts has high potential to add value in-terms of metallic luster, improved strength, long shelf-life and better radiation resistance. Standard acid copper plating process has been adopted for deposition of copper on polymer parts manufactured by fused deposition modelling (FDM) technique. The parameters namely the etching time, voltage and the surface finish of the manufactured FDM parts are studied for their influence on the surface quality. Experiments have been designed using design of experiments strategy. Experiments have been conducted and surface roughness has been measured. Influence of each of the three parameters has been discussed in detail. For the reported process the optimal value of etching time of Acrylonitrile Butadiene Styrene (ABS) has been found in the range of 30 to 60 minutes along with applied voltage in the range of 1.5 to 2.5 Volts for copper electroplating.


2019 ◽  
Vol 25 (4) ◽  
pp. 765-774 ◽  
Author(s):  
Prithvirajan R. ◽  
Sugavaneswaran M. ◽  
Sathishkumar N. ◽  
Arumaikkannu G.

Purpose Custom-designed metal bellows require alternate ways to produce the die to shorten lead time. The purpose of this study is to explore the possibility of using Additive Manufactured (AM) polymer die as direct rapid tool (RT) for metal bellow hydroforming. Design/methodology/approach Finite element analysis (FEA) was used to simulate bellow forming and to evaluate the compatibility of AM die. Fused deposition modelling (FDM) technique is used to fabricate die with Acrylonitrile Butadiene Styrene (ABS) material. To validate, the width of the metal bellow convolutions obtained from the FEA simulation is compared with convolution formed during the experiment. Findings FDM-made die can be used for a short production run of bellow hydroforming. FEA simulation shows that stress developed in some regions of die is less and these regions have potential for material reduction. Use of RT for this particular application is limited by the die material, forming pressure, width, convolution span and material of bellow. This supports the importance of FEA validation of RT before fabrication to evaluate and redesign die for the successful outcome of the tool. Research limitations/implications The given methodology may be followed to design a RT with minimum material consumption for bellow forming application. Whenever there is a change in bellow design or the die material, simulation has to be done to evaluate the capability of the die. As this study was focused on a short production run for manufacturing one or few bellows, the die life is not a significant factor. Originality/value This paper demonstrates about rapid tooling for metal bellow manufacturing using FDM technique for low volume production. Further, FEA is used to identify low stress regions and redesign the die for material reduction before die manufacturing. AM die can be used for developing customized metal bellow for applications such as defense, aerospace, automobiles, etc.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 883
Author(s):  
Othman Laban ◽  
Elsadig Mahdi ◽  
Samahat Samim ◽  
John-John Cabibihan

Recent polymer and metal additive manufacturing technologies were proven capable of building complex structures with high accuracy. Although their final products differ significantly in terms of mechanical properties and building cost, many structural optimization studies were performed with either one without systematic justification. Therefore, this study investigated whether the Direct Metal Laser Sintering (DMLS) and Fused Deposition Modelling (FDM) methodologies can provide similar conclusions when performing geometrical manipulations for optimizing structural crashworthiness. Two identical sets of four shapes of stiffened hexagonal cells were built and crushed under quasi-static loading. The results were compared in terms of collapsing behavior, load-carrying performance, and energy-absorption capability. Although the observed failure modes were different since the base-materials differ, similar improvement trends in performance were observed between both fabrication approaches. Therefore, FDM was recommended as a fabrication method to optimize thin-walled cellular hexagonal parameters since it was 80% more time-efficient and 53.6% cheaper than the DMLS technique.


2017 ◽  
Vol 20 (4) ◽  
pp. 149
Author(s):  
Marta Revilla-Leon ◽  
Marina Olea-Vielba ◽  
Ana Esteso-Díaz ◽  
Iñaki Martinez-Klemm ◽  
Jose Manuel Reuss Rodriguez-Vilaboa ◽  
...  

<p>There are 7 categories for the additive manufacturing (AM) technologies and a wide variety of materials that can be used to build a computer aided designed (CAD) 3-Dimensional (3D) object. The present article reviews the main AM processes for polymers for dental applications: stereolithography (SLA), direct light processing (DLP), material jetting (MJ) and material extrusion (ME). The manufacturing process, accuracy and precision of these methods will be reviewed, as well as, their prosthodontic applications.</p><p> </p><p><strong>Keywords: </strong>3D printing; Additive manufacturing technologies; Direct light processing; Fused deposition modelling; Material extrusion; Material jetting; Multijet printing; Prosthodontics; Stereolitography.</p>


2020 ◽  
Vol 6 (4) ◽  
Author(s):  
H. Kursat Celik ◽  
Ozkan Kose ◽  
Mihaela-Elena Ulmeanu ◽  
Allan E.W. Rennie ◽  
Thomas N. Abram ◽  
...  

During the COVID-19 pandemic, the demand for specific medical equipment such as personal protective equipment (PPE) has rapidly exceeded the available supply around the world. Specifically, simple medical equipment such as medical gloves, aprons, goggles, surgery masks and medical face shields have become highly in demand in the healthcare sector in face of this rapidly developing pandemic. This difficult period strengthens the social solidarity by an extent parallel to the escalation of this pandemic. Education and government institutions, commercial and non‑commercial organisations and individual home makers have produced specific medical equipment by means of additive manufacturing (AM) technology which is the fastest way to create a product, providing their support for urgent demands within the healthcare services. Medical face shields have become a popular item to produce and many design variations and prototypes have been forthcoming. Although AM technology can be used to produce several types of non‑commercial equipment, this rapid manufacturing approach is limited by its longer production time as compared to conventional serial/mass production and the high demand. However, most of the individual designer/maker-based face shields are designed with little appreciation of clinical needs and non‑ergonomic. They also lack of professional product design and are not designed according to additive manufacturing (DfAM) principles. Consequently, production time of up to 4-5 hours for some products of these designs are needed. Therefore, a lighter, more ergonomic, single frame medical face shield without extra components to assemble would be useful, especially for individual designers/makers and non‑commercial producers to increase productivity in a shorter timeframe. In this study, a medical face shield which is competitively lighter, relatively more ergonomic, easy to use and can be assembled without extra components (such as elastic bands, softening materials and clips) was designed. The face shield was produced by AM with relatively shorter production time. Subsequently, finite element analysis-based structural design verification was performed and a three-dimensional (3D) prototype was produced by an OEM 3D printer (Fused Deposition Modelling). This study demonstrated that an original face shield design with less than 10 g material usage per single frame was produced in under 45 minutes of fabrication time. This research also provides a useful product design for additive manufacturing of simple medical equipment such as face shields through advanced engineering design, simulation and additive manufacturing applications as an essential approach to battling coronavirus-like viral pandemics.


2018 ◽  
Vol 919 ◽  
pp. 230-235 ◽  
Author(s):  
Jaroslav Maloch ◽  
Eva Hnátková ◽  
Milan Žaludek ◽  
Petr Krátký

3D printing technology enables the production of functional components in small quantities which can be used as end-use parts. The mechanical properties of the final product define its quality and determine its success or failure in a given application. One at the various additive manufacturing technologies - Fused Deposition Modelling is very often used due to its relatively low cost and the availability of 3D printers and thermoplastic materials. During the process, there are many factors that can affect the mechanical properties of the final product. The temperature of the extrusion nozzle and the layer thickness are two of the basic process parameters. The objective of this work is to investigate the effect of these two processing parameters on the final mechanical properties of the 3D printed samples from acrylonitrile butadiene styrene. Mechanical testing includes the tensile and flexural strength, as well as tensile and flexural modulus.


2021 ◽  
Author(s):  
M. Hossein Sehhat ◽  
Ali Mahdianikhotbesara ◽  
Farzad Yadegari

Abstract Additive Manufacturing (AM) can be deployed for space exploration purposes, such as fabricating different components of robots’ bodies. The produced AM parts should have desirable thermal and mechanical properties to withstand the extreme environmental conditions, including the severe temperature variations on moon or other planets which cause changes in parts’ strengths and may fail their operation. Therefore, the correlation between operational temperature and mechanical properties of AM fabricated parts should be evaluated. In this study, three different types of polymers, including polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and acrylonitrile butadiene styrene (ABS), were used in Fused Deposition Modeling (FDM) process to fabricate several parts. The mechanical properties of produced parts were then investigated at various temperatures to generate knowledge on the correlation between temperature and type of material. When varying the operational temperature during tensile tests, the material’s glass transition temperature was found influential in determining the type of material failure. Among the materials used, ABS showed the best mechanical properties at all temperatures due to its highest glass transmission temperatures. The results of statistical analysis indicated the temperature as the significant factor on tensile strength while the change in material did not show a significant effect.


2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Tiago Rodrigues Dos Santos ◽  
Isla Kalleny Marques Brandão ◽  
Mateus Silva Sant'Ana ◽  
Pedro Henrique dos Santos Alves ◽  
Rana Mayeli Piêgas Taborda ◽  
...  

The present paper proposes the study of the behavior of three thermoplastic materials: acrylonitrile butadiene styrene (ABS), poly(lactic acid) (PLA), and polyethylene glycol terephthalate (PETG), processed by additive manufacturing type fused deposition modelling (FDM) when exposed to low vacuum. The experiment was composed of three moments consisting of tridimensional modeling and manufacturing of the specimens, drying process and vacuum exposure for 24 hours, according to American Society for Testing and Materials (ASTM) D6653/D6653M standards, and bending test for the determination of mechanical properties, based on ASTM D790 standards. The vacuum chamber tests exposed oscillations in the pressure indicating gases releasing from the specimen, but none of the samples showed visible deformations. Subjecting the materials exposed to low vacuum to bending tests and comparing them to the unexposed material, we observed a significant increase in the calculated modulus of elasticity and a change in the slope of graphic force versus deflection in all materials. This behavior demonstrates that it is possible to submit polymeric materials to vacuum, and low vacuum exposure can be a treatment for thermoplastic materials. In the future, a study using a spectrometer will be necessary to verify which gases are present during pressure oscillation in the chamber, thus making it possible to understand which factor has increased the mechanical properties of the materials. In sequence, experiments will be necessary to validate the vacuum exposure as a form of treatment of materials and to verify the possibility of applying thermoplastics commonly used in additive manufacturing for low-impact space applications.


2020 ◽  
Vol 10 (9) ◽  
pp. 3195 ◽  
Author(s):  
Claudio Tosto ◽  
Lorena Saitta ◽  
Eugenio Pergolizzi ◽  
Ignazio Blanco ◽  
Giovanni Celano ◽  
...  

Fused deposition modelling (FDM™) is one of the most promising additive manufacturing technologies and its application in industrial practice is increasingly spreading. Among its successful applications, FDM™ is used in structural applications thanks to the mechanical performances guaranteed by the printed parts. Currently, a shared international standard specifically developed for the testing of FDM™ printed parts is not available. To overcome this limit, we have considered three different tests aimed at characterizing the mechanical properties of technological materials: tensile test (ASTM D638), flexural test (ISO 178) and short-beam shear test (ASTM D2344M). Two aerospace qualified ULTEMTM 9085 resins (i.e., tan and black grades) have been used for printing all specimens by means of an industrial printer (Fortus 400mc). The aim of this research was to improve the understanding of the efficiency of different mechanical tests to characterize materials used for FDM™. For each type of test, the influence on the mechanical properties of the specimen’s materials and geometry was studied using experimental designs. For each test, 22 screening factorial designs were considered and analyzed. The obtained results demonstrated that the use of statistical analysis is recommended to ascertain the real pivotal effects and that specific test standards for FDM™ components are needed to support the development of materials in the additive manufacturing field.


Author(s):  
M.I.M. Sargini ◽  
S.H. Masood ◽  
Suresh Palanisamy ◽  
Elammaran Jayamani ◽  
Ajay Kapoor

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