Articoli di riviste: "Indirect additive manufacturing"

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He, Rujie, Niping Zhou, Keqiang Zhang, Xueqin Zhang, Lu Zhang, Wenqing Wang e Daining Fang. "Progress and challenges towards additive manufacturing of SiC ceramic". Journal of Advanced Ceramics 10, n. 4 (18 luglio 2021): 637–74. http://dx.doi.org/10.1007/s40145-021-0484-z.

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AbstractSilicon carbide (SiC) ceramic and related materials are widely used in various military and engineering fields. The emergence of additive manufacturing (AM) technologies provides a new approach for the fabrication of SiC ceramic products. This article systematically reviews the additive manufacturing technologies of SiC ceramic developed in recent years, including Indirect Additive Manufacturing (Indirect AM) and Direct Additive Manufacturing (Direct AM) technologies. This review also summarizes the key scientific and technological challenges for the additive manufacturing of SiC ceramic, and also forecasts its possible future opportunities. This paper aims to provide a helpful guidance for the additive manufacturing of SiC ceramic and other structural ceramics.

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Khan, Shah Fenner, M. J. German e K. W. Dalgarno. "Indirect Additive Manufacturing Processing of Poly-Lactide-co-Glycolide". Applied Mechanics and Materials 754-755 (aprile 2015): 985–89. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.985.

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The research and development of biomaterials have brought about new treatments in regenerative medicine. The research work presented in this paper focus on the use of Poly-Lactide-co-glycolide (PLGA) in the fabrication of patient specific fracture fixation plate by indirect additive manufacturing method. The use of biopolymers such as PLGA has been seen as a solution to the problems of stress shield and post-surgery inherent in biometal fixation plates. This paper discusses the consequence of this processing method on characteristics and properties of the PLGA. PLGA of ratio 50:50, 65:35 and 85:15 was processed and compared. The granules of PLGA were positioned in the cavity of the stereolithography (SLA) mould and heated under constant pressure with sintering temperature of 73°C for 2.0hours. Both the variation in samples fabricated from this process with the designed model and the changes in material characteristics are below 10%. The flexural strength for PLGA of ratio 50:50, 65:35 and 85:15 is 73.8±2.3MPa, 75.0±2.8, 60.0±11.7, respectively. The characteristics and mechanical tests indicate that the results were comparable with conventional processing of PLGA.

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Aizat, M., e S. F. Khan. "Fabrication of mandible fracture plate by indirect additive manufacturing". Journal of Physics: Conference Series 908 (ottobre 2017): 012063. http://dx.doi.org/10.1088/1742-6596/908/1/012063.

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Carreira, Pedro, Daniel Gatões, Nuno Alves, Ana Sofia Ramos e Maria Teresa Vieira. "Searching New Solutions for NiTi Sensors through Indirect Additive Manufacturing". Materials 15, n. 14 (19 luglio 2022): 5007. http://dx.doi.org/10.3390/ma15145007.

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Shape Memory Alloys (SMAs) can play an essential role in developing novel active sensors for self-healing, including aeronautical systems. However, the NiTi SMAs available in the market are almost limited to wires, small sheets, and coatings. This restriction is mainly due to the difficulty in processing NiTi through conventional processes. Thus, the objective of this study is to evaluate the potential of one of the most promising routes for NiTi additive manufacturing—material extrusion (MEX). Optimizing the different steps during processing is mandatory to avoid brittle secondary phases formation, such as Ni3Ti. The prime NiTi powder is prealloyed, but it also contains NiTi2 and Ni as secondary phases. The present study highlights the role of Ni and NiTi2, with the later having a melting temperature (Tm = 984 °C) lower than the NiTi sintering temperature, thus allowing a welcome liquid phase sintering (LPS). Nevertheless, the reaction of the liquid phase with the Ni phase could contribute to the formation of brittle intermetallic compounds, particularly around NiTi and NiTi2 phases, affecting the final structural properties of the 3D object. The addition of TiH2 to the virgin prealloyed NiTi powder was also studied and revealed the non-formation of Ni3Ti for a specific composition. The balancing addition of extra Ni revealed priority in the Ni3Ti appearance, emphasizing the role of Ni. Feedstocks extruded (filaments) and green strands (layers), before and after debinding & sintering, were used as homothetic of 3D objects for evaluation of defects (microtomography), microstructures, and mechanical properties. The composition of prealloyed powder with 5 wt.% TiH2 addition after sintering showed a homogeneous matrix with the NiTi2 second phase uniformly dispersed.

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Shahzad, Khuram, Jan Deckers, Zhongying Zhang, Jean-Pierre Kruth e Jef Vleugels. "Additive manufacturing of zirconia parts by indirect selective laser sintering". Journal of the European Ceramic Society 34, n. 1 (gennaio 2014): 81–89. http://dx.doi.org/10.1016/j.jeurceramsoc.2013.07.023.

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Abdelaal, Osama, Saied Darwish, Khaled Abd Elmougoud e Saleh Aldahash. "A new methodology for design and manufacturing of a customized silicone partial foot prosthesis using indirect additive manufacturing". International Journal of Artificial Organs 42, n. 11 (24 maggio 2019): 645–57. http://dx.doi.org/10.1177/0391398819847682.

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The production of customized prostheses for the foot and ankle still relies on slow and laborious steps of the traditional plaster molding fabrication techniques. Additive manufacturing techniques where three-dimensional objects can be constructed directly based on the object’s computer-aided-design data in a layerwise manner has opened the door to new opportunities for manufacturing of novel and personalized medical devices. The purpose of the present study was to develop a new methodology for design and manufacturing of a customized silicone partial foot prosthesis via an indirect additive manufacturing process. Furthermore, the biomechanics of gait of a subject with partial foot amputation wearing the custom silicone foot prosthesis manufactured by the indirect additive manufacturing was characterized, in comparison with a matched healthy participant. This study has confirmed the possibility of producing silicone partial foot prosthesis by indirect additive manufacturing procedure. The amputated subject reported total comfort using the custom prosthesis during walking, as well as cosmetic advantages. The prosthesis restored the foot geometry and normalized many of gait characteristics. The findings presented here contribute to introduce a proper understanding of biomechanics of walking after wearing silicone partial foot prosthesis and are useful for prosthetists and rehabilitation therapists when treating patients after partial foot amputation.

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Greeff, G. P. "Material Flow Rate Estimation in Material Extrusion Additive Manufacturing". NCSL International measure 13, n. 1 (2021): 46–56. http://dx.doi.org/10.51843/measure.13.1.5.

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The additive manufacturing of products promises exciting possibilities. Measurement methodologies, which measure an in-process dataset of these products and interpret the results, are essential. However, before developing such a level of quality assurance several in-process measurands must be realized. One of these is the material flow rate, or rate of adding material during the additive manufacturing process. Yet, measuring this rate directly in material extrusion additive manufacturing presents challenges. This work presents two indirect methods to estimate the volumetric flow rate at the liquefier exit in material extrusion, specifically in Fused Deposition Modeling or Fused Filament Fabrication. The methods are cost effective and may be applied in future sensor integration. The first method is an optical filament feed rate and width measurement and the second is based on the liquefier pressure. Both are used to indirectly estimate the volumetric flow rate. The work also includes a description of linking the G-code command to the final print result, which may be used to create a per extrusion command model of the part.

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Snosi, Ahmed Mamdouh, Shaimaa Mohamed Lotfy, Yasmine Galaleldin Thabet, Marwa Ezzat Sabet e Fardos Nabil Rizk. "Subtractive versus additive indirect manufacturing techniques of digitally designed partial dentures". Journal of Advanced Prosthodontics 13, n. 5 (2021): 327. http://dx.doi.org/10.4047/jap.2021.13.5.327.

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Montero, Joaquin, Pablo Vitale, Sebastian Weber, Matthias Bleckmann e Kristin Paetzold. "Indirect Additive Manufacturing of resin components using polyvinyl alcohol sacrificial moulds". Procedia CIRP 91 (2020): 388–95. http://dx.doi.org/10.1016/j.procir.2020.02.191.

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Ramadany, Mohamed, e Mohamed Saad Bajjou. "Applicability and integration of concrete additive manufacturing in construction industry: A case study". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 235, n. 8 (30 gennaio 2021): 1338–48. http://dx.doi.org/10.1177/0954405420986102.

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The spread of additive manufacturing in recent years has broadened the sector of applications, namely in the construction field. This technology enables new functionalities and opportunities to be considered for the construction industry. Indeed, 3D printing processes can directly or indirectly affect the concrete material. Besides the printing processes for concrete structures, there are other indirect uses of 3D concrete printing, such as the manufacture of molds and formwork. However, its integration raises new challenges. This paper is first devoted to the state-of-the-art regarding the use of additive manufacturing in construction through a bibliographical study and an overview of various experiences in different countries. Secondly, the opportunities of such technologies for the construction sector will be discussed. Then, the issues and challenges related to the applicability and integration of concrete additive manufacturing will be highlighted. Finally, a diagnosis of the applicability and integration of concrete additive manufacturing has been made by analyzing the results of a survey of Moroccan professionals. The objective is to raise and identify key factors for successful integration.

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Almonti, Daniele, Gabriele Baiocco, Vincenzo Tagliaferri e Nadia Ucciardello. "Design and Mechanical Characterization of Voronoi Structures Manufactured by Indirect Additive Manufacturing". Materials 13, n. 5 (29 febbraio 2020): 1085. http://dx.doi.org/10.3390/ma13051085.

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Additive manufacturing (AM) is a production process for the fabrication of three-dimensional items characterized by complex geometries. Several technologies employ a localized melting of metal dust through the application of focused energy sources, such as lasers or electron beams, on a powder bed. Despite the high potential of AM, numerous burdens afflict this production technology; for example, the few materials available, thermal stress due to the focused thermal source, low surface finishing, anisotropic properties, and the high cost of raw materials and the manufacturing process. In this paper, the combination by AM of meltable resins with metal casting for an indirect additive manufacturing (I-AM) is proposed. The process is applied to the production of open cells metal foams, similar in shape to the products available in commerce. However, their cellular structure features were designed and optimized by graphical editor Grasshopper®. The metal foams produced by AM were cast with a lost wax process and compared with commercial metal foams by means of compression tests.

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Almonti, Daniele, e Nadia Ucciardello. "Design and Thermal Comparison of Random Structures Realized by Indirect Additive Manufacturing". Materials 12, n. 14 (13 luglio 2019): 2261. http://dx.doi.org/10.3390/ma12142261.

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Additive manufacturing (AM) processes are used to fabricate three-dimensional complex geometries. There are several technologies that use laser or electron beam over metal powder beds. However, the direct AM processes have inconveniences such as specific set of materials, high thermal stress traced, high local energy absorbed, poor surface finish, anisotropic properties, high cost of material powder, and manufacturing with high-power beams. In this paper, an alternative process was developed. An indirect additive manufacturing (I-AM) combining a 3D print of castable resin and metal casting in order to obtain a cellular structure similar in shape to commercial metal foams but completely definable as design features was developed. Design of the cellular structure was made by the graphical algorithm editor Grasshopper®. Designed structures were realized by a lost-wax casting process and compared with commercial foam specimens by a system designed for this work. The designed metal foams showed a performance superior to that of commercial metal foam; in particular, the heat thermal coefficient of designed metal foams in the better case was 870 W/m2·K, almost doubled in comparison with the commercial foam tested in this work.

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Ortega Varela de Seijas, Manuel, Andreas Bardenhagen, Thomas Rohr e Enrico Stoll. "Indirect Induction Sintering of Metal Parts Produced through Material Extrusion Additive Manufacturing". Materials 16, n. 2 (16 gennaio 2023): 885. http://dx.doi.org/10.3390/ma16020885.

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Avoiding loose powders and resins, material extrusion additive manufacturing is a powerful technique to produce near-net shape parts, being a cheap and safe alternative for developing complex industrial-grade products. Filaments embedded with a high packing density of metallic or ceramic granules are being increasingly used, resulting in almost fully dense parts, whereby geometries are shaped, debinded and sintered sequentially until the completion of the part. Traditionally, “brown” debinded geometries are transported to conventional furnaces to densify the powder compacts, requiring careful tailoring of the heating profiles and sintering environment. This approach is decoupled and often involves time-consuming post-processing, whereby after the completion of the shaping and debinding steps, the parts need to be transported to a sintering furnace. Here, it is shown that sintering via indirect induction heating of a highly filled commercially available filament embedded with stainless steel 316L powder can be an effective route to densify Fused Filament Fabricated (FFF) parts. The results show that densities of 99.8% can be reached with very short soaking times, representing a significant improvement compared to prior methods. A hybrid machine is proposed, whereby a custom-built machine is integrated with an induction heater to combine FFF with local indirect induction sintering. Sintering in situ, without the need for part transportation, simplifies the processing of metal parts produced through material extrusion additive manufacturing.

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Gupta, Surojit, Daniel Trieff, Mackenzie Short, Maharshi Dey, Samuel J. A. Hocker e Valerie Wiesner. "A Review of Additive Manufacturing Processes for Fabricating Ceramics and Composites". AM&P Technical Articles 181, n. 3 (1 aprile 2023): 23–27. http://dx.doi.org/10.31399/asm.amp.2023-03.p023.

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Abstract This article reviews additive manufacturing technologies that can be used for manufacturing ceramics and ceramic-based composites. Stereolithography and associated techniques offer the possibility of producing ceramic components with finer resolution. Powder-based techniques like binder jetting and indirect selective laser sintering can be used for designing porous ceramics. Selective laser melting offers practitioners the option of manufacturing ceramics with minimal post-processing requirements, although further research is needed to decrease its cost.

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Öberg, Christina. "Additive manufacturing – digitally changing the global business landscape". European Journal of Management and Business Economics 28, n. 2 (8 luglio 2019): 174–88. http://dx.doi.org/10.1108/ejmbe-11-2018-0116.

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Purpose Additive manufacturing, that is, layer-based manufacturing technologies, is thought to change supply chain operations from global to local, while also affecting design processes and product structures. As this transformation happens, a power struggle among various actors relating themselves to additive manufacturing has emerged. The purpose of this paper is to discuss and explain the development of additive manufacturing from a power dependence point of view. Design/methodology/approach The paper is based on data collected from a number of seminars hosting a total of 620 industry experts representing 102 companies in the area, and reflecting every step of the supply chain. Findings The paper points out how measures to deal and create power imbalances occur also related to indirect parties, and how the disruptive character of the supply chain leads to exercised power. Originality/value The power struggle provides new insights into how an emerging technology is realised and the effect of protectionism on such attempts. Specifically related to additive manufacturing, the paper illustrates the business side from various actors’ point of view, which adds to technological perspectives on additive manufacturing, as well as studies viewing the supply chain from a bird’s-eye perspective.

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Santos, Cyril, Daniel Gatões, Fábio Cerejo e Maria Teresa Vieira. "Influence of Metallic Powder Characteristics on Extruded Feedstock Performance for Indirect Additive Manufacturing". Materials 14, n. 23 (24 novembre 2021): 7136. http://dx.doi.org/10.3390/ma14237136.

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Material extrusion (MEX) of metallic powder-based filaments has shown great potential as an additive manufacturing (AM) technology. MEX provides an easy solution as an alternative to direct additive manufacturing technologies (e.g., Selective Laser Melting, Electron Beam Melting, Direct Energy Deposition) for problematic metallic powders such as copper, essential due to its reflectivity and thermal conductivity. MEX, an indirect AM technology, consists of five steps—optimisation of mixing of metal powder, binder, and additives (feedstock); filament production; shaping from strands; debinding; sintering. The great challenge in MEX is, undoubtedly, filament manufacturing for optimal green density, and consequently the best sintered properties. The filament, to be extrudable, must accomplish at optimal powder volume concentration (CPVC) with good rheological performance, flexibility, and stiffness. In this study, a feedstock composition (similar binder, additives, and CPVC; 61 vol. %) of copper powder with three different particle powder characteristics was selected in order to highlight their role in the final product. The quality of the filaments, strands, and 3D objects was analysed by micro-CT, highlighting the influence of the different powder characteristics on the homogeneity and defects of the greens; sintered quality was also analysed regarding microstructure and hardness. The filament based on particles powder with D50 close to 11 µm, and straight distribution of particles size showed the best homogeneity and the lowest defects.

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Kalman, Les, e Lyndsay Desimone. "A novel workflow for indirect cobalt-chromium restorations using additive manufacturing without digital design". Journal of Dental Research, Dental Clinics, Dental Prospects 15, n. 3 (25 agosto 2021): 147–51. http://dx.doi.org/10.34172/joddd.2021.025.

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This preliminary investigation explored additive manufacturing to fabricate cobalt-chromium onlay restorations without the use of digital design. Extracted molars were prepared for four-surface onlays followed by the conventional approach for the fabrication of provisionals. The provisionals were digitized with an intraoral scanner, and stereolithography (STL) files were fabricated with additive manufacturing in cobalt-chromium, utilizing selective laser melting (SLM). Onlays were bonded to the corresponding tooth. Restorations were polished after cementation and assessed with photography, radiography, and a clinical post-cementation checklist. Cementation was unremarkable; marginal adaption and surface finish were generally acceptable. A simple, efficient, and inexpensive alternative workflow for the fabrication of indirect restorations without using the digital design is proposed.

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Chen, Chih-Hao, Jolene Liu, Chee-Kai Chua, Siaw-Meng Chou, Victor Shyu e Jyh-Ping Chen. "Cartilage Tissue Engineering with Silk Fibroin Scaffolds Fabricated by Indirect Additive Manufacturing Technology". Materials 7, n. 3 (13 marzo 2014): 2104–19. http://dx.doi.org/10.3390/ma7032104.

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Shahzad, Khuram, Jan Deckers, Jean-Pierre Kruth e Jef Vleugels. "Additive manufacturing of alumina parts by indirect selective laser sintering and post processing". Journal of Materials Processing Technology 213, n. 9 (settembre 2013): 1484–94. http://dx.doi.org/10.1016/j.jmatprotec.2013.03.014.

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Soe, Shwe Pyi, Daniel Roy Eyers, Chi Hieu Le e Awanis Romli. "Additive Tooling for Tube Hydroforming". Key Engineering Materials 572 (settembre 2013): 269–72. http://dx.doi.org/10.4028/www.scientific.net/kem.572.269.

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The use of tube hydroforming in manufacturing is increasing in popularity, particularly in automotive applications where it offers numerous cost and well-recognized performance advantages over conventional stamping and welding processes. In this paper, the use of indirect Additive Tooling is explored in the creation of tool inserts to be used in the production of exhaust manifolds for the automotive industry. The principal focus of this research concerns the identification of operational issues arising from the exploitation of Additive Tooling, together with the suggestion of a number of techniques and solutions which may be applied to mitigate the problems inherent in the rapid manufacture of tube hydroforming tools.

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Khan, S. F., Kenneth W. Dalgarno e Rakhmad Arief Siregar. "Indirect Additive Manufacturing (AM) of Apatite-Wollastonite (A-W) Glass-Ceramic for Medical Implants". Applied Mechanics and Materials 786 (agosto 2015): 354–60. http://dx.doi.org/10.4028/www.scientific.net/amm.786.354.

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Bone replacements for congenital defects, cancer resections, and traumas are typically performed using bone grafting. However, due to scarcity of the source material, synthetic materials for bone replacements are sometimes used instead. Unfortunately, the ability to engineer anatomically correct pieces of viable and functional human bone are difficult and time-consuming through conventional manufacturing methods. This paper proposes an alternative route which incorporates the use of AM technology for fabricating patient-specific implants. The implants were computer-aided design (CAD) from a stereolithography (STL) file of a mandible. AM method was combined with lost wax casting (LWC) technology to produce the customised A-W glass-ceramic implants. An initial study of sintered A-W was performed on cylindrical samples show on average 19.8% porous with on average 75% of the porosity being open and an average flexural strength of 82.6 MPa. The A-W scaffolds display a degree of macro-and micro porosity. The geometrical shape of the A-W implants shows a close resemblance to the required implant. Additive manufacturing assisted fabrication of A-W glass-ceramic provides a promising method for manufacturing customised medical implants.

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Romani, Alessia, Stefan Caba, Raffaella Suriano e Marinella Levi. "Recycling Glass and Carbon Fibers for Reusable Components in the Automotive Sector through Additive Manufacturing". Applied Sciences 13, n. 10 (9 maggio 2023): 5848. http://dx.doi.org/10.3390/app13105848.

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This work explores the use of additive manufacturing (AM) to reprocess recycled glass and carbon fibers in the automotive sector. It aims to foster exploitation of recycled Glass Fiber Reinforced Polymers (rGFRPs) and recycled Carbon Fiber Reinforced Polymers (rCFRPs) through two manufacturing workflows: indirect Fused Filament Fabrication (FFF) and UV-assisted Direct Ink Writing (UV-DIW). An industrial case study on vehicle components has been considered by prototyping one real component. After the tensile tests, some molds were fabricated with a FFF 3D printer for the indirect 3D printing process to cast an epoxy-based thermosetting resin with rGFs and rCFs. The second technology consisted in fabricating the parts by hardening in-situ a photo- and thermal-curable thermosetting acrylic liquid resin with rGFs. These results validate the use of AM and recycled composites for applications in the automotive sector. These approaches may be implemented for customizable components for batches below 100 vehicles as the first step for their exploitation.

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Li, Yan, Dichen Li, Bingheng Lu, Dajing Gao e Jack Zhou. "Current status of additive manufacturing for tissue engineering scaffold". Rapid Prototyping Journal 21, n. 6 (19 ottobre 2015): 747–62. http://dx.doi.org/10.1108/rpj-03-2014-0029.

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Purpose – The purpose of this paper is to review the current status of additive manufacturing (AM) used for tissue engineering (TE) scaffold. AM processes are identified as an effective method for fabricating geometrically complex objects directly from computer models or three-dimensional digital representations. The use of AM technologies in the field of TE has grown rapidly in the past 10 years. Design/methodology/approach – The processes, materials, precision, applications of different AM technologies and their modified versions used for TE scaffold are presented. Additionally, future directions of AM used for TE scaffold are also discussed. Findings – There are two principal routes for the fabrication of scaffolds by AM: direct and indirect routes. According to the working principle, the AM technologies used for TE scaffold can be generally classified into: laser-based; nozzle-based; and hybrid. Although a number of materials and fabrication techniques have been developed, each AM technique is a process based on the unique property of the raw materials applied. The fabrication of TE scaffolds faces a variety of challenges, such as expanding the range of materials, improving precision and adapting to complex scaffold structures. Originality/value – This review presents the latest research regarding AM used for TE scaffold. The information available in this paper helps researchers, scholars and graduate students to get a quick overview on the recent research of AM used for TE scaffold and identify new research directions for AM in TE.

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Cerejo, Fábio, Daniel Gatões e M. T. Vieira. "Optimization of metallic powder filaments for additive manufacturing extrusion (MEX)". International Journal of Advanced Manufacturing Technology 115, n. 7-8 (25 maggio 2021): 2449–64. http://dx.doi.org/10.1007/s00170-021-07043-0.

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AbstractAdditive manufacturing (AM) of metallic powder particles has been establishing itself as sustainable, whatever the technology selected. Material extrusion (MEX) integrates the ongoing effort to improve AM sustainability, in which low-cost equipment is associated with a decrease of powder waste during manufacturing. MEX has been gaining increasing interest for building 3D functional/structural metallic parts because it incorporates the consolidated knowledge from powder injection moulding/extrusion feedstocks into the AM scope—filament extrusion layer-by-layer. Moreover, MEX as an indirect process can overcome some of the technical limitations of direct AM processes (laser/electron-beam-based) regarding energy-matter interactions. The present study reveals an optimal methodology to produce MEX filament feedstocks (metallic powder, binder, and additives), having in mind to attain the highest metallic powder content. Nevertheless, the main challenges are also to achieve high extrudability and a suitable ratio between stiffness and flexibility. The metallic powder volume content (vol.%) in the feedstocks was evaluated by the critical powder volume concentration (CPVC). Subsequently, the rheology of the feedstocks was established by means of the mixing torque value, which is related to the filament extrudability performance.

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Lynch, Paul, C. R. Hasbrouck, Joseph Wilck, Michael Kay e Guha Manogharan. "Challenges and opportunities to integrate the oldest and newest manufacturing processes: metal casting and additive manufacturing". Rapid Prototyping Journal 26, n. 6 (10 giugno 2020): 1145–54. http://dx.doi.org/10.1108/rpj-10-2019-0277.

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Purpose This paper aims to investigate the current state, technological challenges, economic opportunities and future directions in the growing “indirect” hybrid manufacturing ecosystem, which integrates traditional metal casting with the production of tooling via additive manufacturing (AM) process including three-dimensional sand printing (3DSP) and printed wax patterns. Design/methodology/approach A survey was conducted among 100 participants from foundries and AM service providers across the USA to understand the current adoption of AM in metal casting as a function of engineering specifications, production demand, volume and cost metrics. In addition, current technological and logistical challenges that are encountered by the foundries are identified to gather insight into the future direction of this evolving supply chain. Findings One of the major findings from this study is that hard tooling costs (i.e. patterns/core boxes) are the greatest challenge in low volume production for foundries. Hence, AM and 3DSP offer the greatest cost-benefit for these low volume production runs as it does not require the need for hard tooling to produce much higher profit premium castings. It is evident that there are major opportunities for the casting supply chain to benefit from an advanced digital ecosystem that seamlessly integrates AM and 3DSP into foundry operations. The critical challenges for adoption of 3DSP in current foundry operations are categorized into as follows: capital cost of the equipment, which cannot be justified due to limited demand for 3DSP molds/cores by casting buyers, transportation of 3DSP molds and cores, access to 3DSP, limited knowledge of 3DSP, limitations in current design tools to integrate 3DSP design principles and long lead times to acquire 3DSP molds/cores. Practical implications Based on the findings of this study, indirect hybrid metal AM supply chains, i.e. 3DSP metal casting supply chains is proposed, as 3DSP replaces traditional mold-making in the sand casting process flow, no/limited additional costs and resources would be required for qualification and certification of the cast parts made from three-dimensional printed sand molds. Access to 3DSP resources can be addressed by establishing a robust 3DSP metal casting supply chain, which will also enable existing foundries to rapidly acquire new 3DSP-related knowledge. Originality/value This original survey from 100 small and medium enterprises including foundries and AM service providers suggests that establishing 3DSP hubs around original equipment manufacturers as a shared resource to produce molds and cores would be beneficial. This provides traditional foundries means to continue mass production of castings using existing hard tooling while integrating 3DSP for new complex low volume parts, replacement parts, legacy parts and prototyping.

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Santos, R. F., A. R. Farinha, R. Rocha, C. Batista, G. Costa Rodrigues e M. T. Vieira. "High-speed machining tool-steel chips as an outstanding raw material for indirect additive manufacturing?" Results in Materials 11 (settembre 2021): 100207. http://dx.doi.org/10.1016/j.rinma.2021.100207.

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Asriyanti, Asriyanti, Kushendarsyah Saptaji, Nisa Khoiriyah, Muhammad Satrio Utomo, Made Subekti Dwijaya, Farid Triawan e Muhammad Hanif Nadhif. "Fabrication of Rigid Polyurethane Foam Lumbar Spine Model for Surgical Training using Indirect Additive Manufacturing". International Journal of Technology 13, n. 8 (28 dicembre 2022): 1612. http://dx.doi.org/10.14716/ijtech.v13i8.6125.

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Placzek, Gerrit, e Patrick Schwerdtner. "Concrete Additive Manufacturing in Construction: Integration Based on Component-Related Fabrication Strategies". Buildings 13, n. 7 (11 luglio 2023): 1769. http://dx.doi.org/10.3390/buildings13071769.

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Additive manufacturing (AM) with concrete, also known as concrete 3D printing, is one of the most interesting approaches for disrupting the construction industry and is currently subject to numerous research activities worldwide. AM has great potential to decrease labour costs and increase the material efficiency and geometric complexity of non-standardised building components. Although prior investigations have shown various fields of application for AM with concrete, the full potential with respect to different structural component types has not been covered yet. With this paper, an up-to-date review of fabrication strategies for the main structural components, (1) walls, (2) columns, (3) slabs, and (4) beams, is provided to identify trends and existing challenges. Therefore, firstly, AM methods and their underlying principles and characteristics for concrete components are presented, and secondly, fabrication strategies for each AM method are shown. The investigation uncovers different AM strategies (direct part vs. indirect “permanent formwork”; in situ, on-site, or off-site), which are currently being used. As a result, future applications of AM will require a hybrid manufacturing strategy combining conventional and additive manufacturing to fully explore its potential.

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Moreira, Mariana F., Akel F. Kanaan e Ana P. Piedade. "Indirect Additive Manufacturing: A Valid Approach to Modulate Sorption/Release Profile of Molecules from Chitosan Hydrogels". Polymers 14, n. 13 (21 giugno 2022): 2530. http://dx.doi.org/10.3390/polym14132530.

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This work studied the influence of hydrogel’s physical properties (geometry and hierarchical roughness) on the in vitro sorption/release profiles of molecules. To achieve this goal, chitosan (CS) solutions were cast in 3D-printed (3DP) molds presenting intricate shapes (cubic and half-spherical with/without macro surface roughness) and further immersed in alkaline solutions of NaOH and NaCl. The resulting physically crosslinked hydrogels were mechanically stable in aqueous environments and successfully presented the shapes and geometries imparted by the 3DP molds. Sorption and release profiles were evaluated using methyl orange (MO) and paracetamol (PMOL) as model molecules, respectively. Results revealed that distinct MO sorption/PMOL release profiles were obtained according to the sample’s shape and presence/absence of hierarchical roughness. MO sorption capacity of CS samples presented both dependencies of hierarchical surface and geometry parameters. Hence, cubic samples without a hierarchical surface presented the highest (up to 1.2 × greater) dye removal capacity. Moreover, PMOL release measurements were more dependent on the surface area of hydrogels, where semi-spherical samples with hierarchical roughness presented the fastest (~1.13 × faster) drug delivery profiles. This work demonstrates that indirect 3DP (via fused filament fabrication (FFF) technology) could be a simple strategy to obtain hydrogels with distinct sorption/release profiles.

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Sapkal, Pranav S., Abhaykumar M. Kuthe, Rajpal S. Kashyap, Amit R. Nayak, Sudhanshu A. Kuthe e Anuja P. Kawle. "Indirect fabrication of hydroxyapatite/β-tricalcium phosphate scaffold for osseous tissue formation using additive manufacturing technology". Journal of Porous Materials 23, n. 6 (9 giugno 2016): 1567–74. http://dx.doi.org/10.1007/s10934-016-0217-9.

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Poier, Paloma Hohmann, Rodrigo Pulido Arce, Gabriel Chemin Rosenmann, Maria Gabriela Reis Carvalho, Leandra Ulbricht e José Aguiomar Foggiatto. "Development of modular wrist, hand and finger orthesis by additive manufacturing". Research, Society and Development 10, n. 15 (27 novembre 2021): e333101522707. http://dx.doi.org/10.33448/rsd-v10i15.22707.

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Additive Manufacturing (AM) has been considered an innovative technology for the development of orthoses. Even so, the use of AM, utilizing low cost rigid and flexible material which can be used in different ways by the same user, to produce a modular orthosis has yet to be explored. Purpose: Develop a modular wrist, hand and finger orthosis that can be utilized as a functional or static orthosis, depending on the therapeutic objective. This being produced by low cost Additive Manufacturing, through a single anatomy acquisition process. Approach: Firstly, requirements for modularization and development were defined in a team with occupational therapists and mechanical engineers, After indirect anatomy acquisition of a volunteer, without disabilities, two parts of the same orthosis were modeled, one flexible (functional) and the other rigid (static). These were printed on PLA (rigid part) and flexible TPU (functional part) with an Open Source printer. In addition, fastening strips were also made in flexible TPU. Findings: Three parts of which make up the modular orthosis were produced. This can be used in two different ways; one being to maintain the static posture of the wrist, hand and fingers and the other to provide functionality of the hands, but with the correct positioning of the wrist and thumb. Originality: Even with low-cost material and an open source machine, it was possible to generate an innovative proposal with the use of AM as the orthosis manufacturing process.

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Delic, Mia, Daniel R. Eyers e Josip Mikulic. "Additive manufacturing: empirical evidence for supply chain integration and performance from the automotive industry". Supply Chain Management: An International Journal 24, n. 5 (19 agosto 2019): 604–21. http://dx.doi.org/10.1108/scm-12-2017-0406.

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Purpose Additive Manufacturing offers much potential for industry, but at the same time is likely to have a significant impact on supply chain theory and practice. To-date there has been limited empirical work exploring the effect of Additive Manufacturing, and this study aims to provide a detailed appraisal of how supply chain integration, supply chain performance and firm performance may be affected by the adoption of Additive Manufacturing. These are critical factors for supply chain management, but have received little quantified attention to date. Design/methodology/approach A theoretical model is developed from a detailed review of the literature, from which a quantitative analysis is performed. Using data collected from 124 automotive manufacturers in European Union and the partial least square- structural equation modeling method, the research examines the relationships among different dimensions of supply chain integration, supply chain performance and firm performance from the perspective of Additive Manufacturing adoption. Findings The findings indicate that Additive Manufacturing adoption positively influences supply chain performance and as a consequence, firm performance. In addition, supporting the resource-based view perspective, the results show a positive indirect effect of supply chain integration on the supply chain and firm performance improvements, enabled by the Additive Manufacturing adoption. This helps to explain some inconsistent findings in previous research regarding the impacts of supply chain integration on performance. Research limitations/implications The results of this study support the view that Additive Manufacturing can make a positive contribution to the supply chain, but this is not achieved solely by the technologies alone. Many of the traditional activities of supply chain management (i.e. integration) are still needed when using Additive Manufacturing, and research needs to understand whether Additive Manufacturing adoption will necessitate changes to the way these traditional activities are undertaken. Building on the findings of the current study, much more work is therefore needed to understand how operations within the supply chain may be changed, and how this may affect the integration and performance of the supply chain. Practical implications This study provides quantitative evidence to show that the adoption of Additive Manufacturing has the potential to affect both firm and supply chain performance. This is significant for those companies considering the adoption of Additive Manufacturing, and may serve as a valuable insight in the strategic decision-making process. For those already using Additive Manufacturing, this study serves to underline the potential for firm performance to be influenced, by focusing on improvements to their production strategies and policies. Originality/value This study provides an initial insight into some fundamental supply chain concepts within an Additive Manufacturing context, which have received very little research attention. It develops a novel conceptual model, and through a large-scale industry survey provides quantified evidence of the impact of Additive Manufacturing on the supply chain. To date, much of the supply chain research is exploratory and qualitative; the quantitative evidence presented in this work, therefore, makes an important and original contribution to both research and practice.

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Tony, Anthony, Ildiko Badea, Chun Yang, Yuyi Liu, Garth Wells, Kemin Wang, Ruixue Yin, Hongbo Zhang e Wenjun Zhang. "The Additive Manufacturing Approach to Polydimethylsiloxane (PDMS) Microfluidic Devices: Review and Future Directions". Polymers 15, n. 8 (18 aprile 2023): 1926. http://dx.doi.org/10.3390/polym15081926.

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This paper presents a comprehensive review of the literature for fabricating PDMS microfluidic devices by employing additive manufacturing (AM) processes. AM processes for PDMS microfluidic devices are first classified into (i) the direct printing approach and (ii) the indirect printing approach. The scope of the review covers both approaches, though the focus is on the printed mold approach, which is a kind of the so-called replica mold approach or soft lithography approach. This approach is, in essence, casting PDMS materials with the mold which is printed. The paper also includes our on-going effort on the printed mold approach. The main contribution of this paper is the identification of knowledge gaps and elaboration of future work toward closing the knowledge gaps in fabrication of PDMS microfluidic devices. The second contribution is the development of a novel classification of AM processes from design thinking. There is also a contribution in clarifying confusion in the literature regarding the soft lithography technique; this classification has provided a consistent ontology in the sub-field of the fabrication of microfluidic devices involving AM processes.

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Wu, Dongting, Qi An, Fuxin Du, Kenji Matsuda, Yingwen Tang e Yong Zou. "Microstructure and corrosion resistance of stainless steel produced by bypass coupling twin-wire indirect arc additive manufacturing". International Journal of Advanced Manufacturing Technology 119, n. 3-4 (3 dicembre 2021): 2159–72. http://dx.doi.org/10.1007/s00170-021-08343-1.

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Cheng, P. Y., e S. F. Khan. "Dimensional accuracy and surface finish of investment casting parts by indirect additive manufacturing from fused filament fabrication". IOP Conference Series: Materials Science and Engineering 429 (9 novembre 2018): 012100. http://dx.doi.org/10.1088/1757-899x/429/1/012100.

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Mun, Jiwon, Byoung-Gwan Yun, Jaehyung Ju e Byung-Moon Chang. "Indirect additive manufacturing based casting of a periodic 3D cellular metal – Flow simulation of molten aluminum alloy". Journal of Manufacturing Processes 17 (gennaio 2015): 28–40. http://dx.doi.org/10.1016/j.jmapro.2014.11.001.

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Mariani, Marco, Elisa Mercadelli, Laura Cangini, Carlo Baldisserri, Carmen Galassi, Claudio Capiani e Nora Lecis. "Additive Manufacturing of Piezoelectric Niobium-Doped Lead Zirconate Titanate (PZT-N) by Binder Jetting". Crystals 13, n. 6 (27 maggio 2023): 883. http://dx.doi.org/10.3390/cryst13060883.

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Binder jetting is an emerging indirect additive manufacturing technique for ceramic materials, which could be employed to produce application-oriented designed components impossible to achieve with traditional processes and featuring enhanced performances. In our study, niobium-doped lead zirconate titanate (PZT-N) powder, usually processed through the standard press-and-sinter route, was employed as the raw material. First, the powder was characterized in terms of granulometry and flowability to assess its suitability for the printing process. Then, shaping by binder jetting was studied, and the effect of three levels of binder saturation (75–90–105%) on the green bodies was assessed. Finally, the microstructure of the sintered samples was studied using SEM, to investigate the effect of thermal treatments on the grain size distribution and residual porosity (~40%). The piezoelectric properties were measured and compared to those of conventionally processed material. The piezoelectric charge and voltage constants (d33 and g33) were evaluated to determine the possible use of printed parts as porous piezoelectric components to be exploited in hydrophones in the direct mode.

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Al-Qahtani, Amal S., Huda I. Tulbah, Mashael Binhasan, Maria S. Abbasi, Naseer Ahmed, Sara Shabib, Imran Farooq et al. "Surface Properties of Polymer Resins Fabricated with Subtractive and Additive Manufacturing Techniques". Polymers 13, n. 23 (24 novembre 2021): 4077. http://dx.doi.org/10.3390/polym13234077.

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This study aimed to compare the surface roughness, hardness, and flexure strength of interim indirect resin restorations fabricated with CAD-CAM (CC), 3D printing (3D), and conventional techniques (CV). Twenty disk (3 mm × Ø10 mm) and ten bar specimens (25 × 2 × 2 mm) were fabricated for the CC, 3D, and CV groups, to be used for surface roughness, micro-hardness, and flexural strength testing using standardized protocol. Three indentations for Vickers micro-hardness (VHN) were performed on each disk and an average was identified for each specimen. Surface micro-roughness (Ra) was calculated in micrometers (μm) using a 3D optical non-contact surface microscope. A three-point bending test with a universal testing machine was utilized for assessing flexural strength. The load was applied at a crosshead speed of 3 mm/min over a distance of 25 mm until fracture. Means and standard deviations were compared using ANOVA and post hoc Tukey–Kramer tests, and a p-value of ≤0.05 was considered statistically significant. Ra was significantly different among the study groups (p < 0.05). Surface roughness among the CC and CV groups was statistically comparable (p > 0.05). However, 3D showed significantly higher Ra compared to CC and CV samples (p < 0.05). Micro-hardness was significantly higher in 3D samples (p < 0.05) compared to CC and CV specimens. In addition, CC and CV showed comparable micro-hardness (p > 0.05). A significant difference in flexural strength was observed among the study groups (p < 0.05). CC and 3D showed comparable strength outcomes (p > 0.05), although CV specimens showed significantly lower (p < 0.05) strength compared to CC and 3D samples. The 3D-printed provisional restorative resins showed flexural strength and micro-hardness comparable to CAD-CAM fabricated specimens, and surface micro-roughness for printed specimens was considerably higher compared to CAD-CAM and conventional fabrication techniques.

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Galati, Manuela, e Paolo Minetola. "Analysis of Density, Roughness, and Accuracy of the Atomic Diffusion Additive Manufacturing (ADAM) Process for Metal Parts". Materials 12, n. 24 (9 dicembre 2019): 4122. http://dx.doi.org/10.3390/ma12244122.

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Atomic Diffusion Additive Manufacturing (ADAM) is a recent layer-wise process patented by Markforged for metals based on material extrusion. ADAM can be classified as an indirect additive manufacturing process in which a filament of metal powder encased in a plastic binder is used. After the fabrication of a green part, the plastic binder is removed by the post-treatments of washing and sintering (frittage). The aim of this work is to provide a preliminary characterisation of the ADAM process using Markforged Metal X, the unique system currently available on the market. Particularly, the density of printed 17-4 PH material is investigated, varying the layer thickness and the sample size. The dimensional accuracy of the ADAM process is evaluated using the ISO IT grades of a reference artefact. Due to the deposition strategy, the final density of the material results in being strongly dependent on the layer thickness and the size of the sample. The density of the material is low if compared to the material processed by powder bed AM processes. The superficial roughness is strongly dependent upon the layer thickness, but higher than that of other metal additive manufacturing processes because of the use of raw material in the filament form. The accuracy of the process achieves the IT13 grade that is comparable to that of traditional processes for the production of semi-finished metal parts.

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Khan, S. F., M. A. Zaidan e L. Tajul. "Lightweight design of Knee-Ankle-Foot Orthotic Devices using Voronoi patterns for Additive Manufacturing". Journal of Physics: Conference Series 2643, n. 1 (1 novembre 2023): 012007. http://dx.doi.org/10.1088/1742-6596/2643/1/012007.

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Abstract Traditionally fabricated knee-ankle-foot orthosis (KAFO) device that is used to aid in the mobility user is uncomfortable. Problems such as weight and enclosure in almost all the part of the leg make it strenuous and humid for the user to wear for a long time. Furthermore, in the traditional production method, it can take up to a week to fabricate. The aim of this study is to redesign the knee-ankle-foot-orthosis by using the application of topology optimization in order to reduce the material used on the product and to make it lightweight. The parameters of the KAFO were determined by using indirect method; similar to traditional method. The modelling and analysis of the KAFO is completed by using CAD and CAE software. Optimization of the product is performed by redesigning the shape and applying topology optimization function. It is able to reduce the maximum stress of the product by 22.56% and the volume by 4.33%. Application of the Voronoi pattern further reduces the mass of the KAFO and produces more organic looks to the product. SLS Lisa Pro 3D printer is used to produce the KAFO in a period of less than a week. This prove to be a viable alternative for producing customized KAFO.

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Deckers, Jan Patrick, Khuram Shahzad, Ludwig Cardon, Marleen Rombouts, Jozef Vleugels e Jean-Pierre Kruth. "Shaping ceramics through indirect selective laser sintering". Rapid Prototyping Journal 22, n. 3 (18 aprile 2016): 544–58. http://dx.doi.org/10.1108/rpj-10-2014-0143.

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Purpose The purpose of this paper is to compare different powder metallurgy (PM) processes to produce ceramic parts through additive manufacturing (AM). This creates the potential to rapidly shape ceramic parts with an almost unlimited shape freedom. In this paper, alumina (Al2O3) parts are produced, as Al2O3 is currently the most commonly used ceramic material for technical applications. Design/methodology/approach Variants of the following PM route, with indirect selective laser sintering (indirect SLS) as the AM shaping step, are explored to produce ceramic parts: powder synthesis, indirect SLS, binder removal and furnace sintering and alternative densification steps. Findings Freeform-shaped Al2O3 parts with densities up to approximately 90 per cent are obtained. Research limitations/implications The resulting Al2O3 parts contain inter-agglomerate pores. To produce higher-quality ceramic parts through indirect SLS, these pores should be avoided or eliminated. Originality/value The research is innovative in many ways. First, composite powders are produced using different powder production methods, such as temperature-induced phase separation and dispersion polymerization. Second, four different binder materials are investigated: polyamide (nylon-12), polystyrene, polypropylene and a carnauba wax – low-density polyethylene combination. Further, to produce ceramic parts with increased density, the following densification techniques are investigated as additional steps of the PM process: laser remelting, isostatic pressing and infiltration.

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Dwivedi, Gourav, Samir K. Srivastava e Rajiv K. Srivastava. "Analysis of barriers to implement additive manufacturing technology in the Indian automotive sector". International Journal of Physical Distribution & Logistics Management 47, n. 10 (6 novembre 2017): 972–91. http://dx.doi.org/10.1108/ijpdlm-07-2017-0222.

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Purpose A spurt in the usage of additive manufacturing (AM) is observed in industrial applications to produce final parts along with rapid prototyping and rapid tooling. Despite the potential benefits of on-demand and on-location production of customised or complex shape parts, widespread implementation of this disruptive production technology is not yet visible. The purpose of this paper is to examine the various barriers to implement AM in the Indian automotive sector and analyse interrelations among them. Design/methodology/approach Based on the extant literature and discussions with industry experts, ten major barriers are identified. The authors use a modified Fuzzy interpretive structural modelling (Fuzzy-ISM) method to derive strengths of relationships among these barriers, develop hierarchical levels, and thereafter group and rank these barriers. Findings ISM diagraph is developed to demonstrate how the barriers drive one another. Production technology capabilities and government support emerge as the most critical factors, with high driving power and medium dependence. Research limitations/implications While identified barriers may be similar across the automotive industry, generalisation of results for interrelationships and ranks in other industries may be limited. Practical implications The findings may be useful to managers to develop suitable mitigation strategies, and take more informed decisions, with individual focus, level focus or cluster focus. Social implications Findings clearly establish that the role of management and government is crucial in mitigating workers’ resistance to AM implementation. Originality/value This paper contributes to AM literature by the structured presentation of the barriers to implement AM in the Indian automotive sector. It also extends the Fuzzy-ISM method by presenting calculation of indirect relations using the appropriate max-product composition and in ranking the barriers.

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Abele, E., J. Claar, S. Dietz e G. Pfeiffer. "Vermessung von Kleinstbearbeitungsmaschinen*/Measurement of micro machine tools". wt Werkstattstechnik online 105, n. 01-02 (2015): 8–12. http://dx.doi.org/10.37544/1436-4980-2015-01-02-10.

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Mit der Etablierung von kleinen Bearbeitungsmaschinen im Bereich der dentalen Technologie wurde ein neuer Markt und Anwenderkreis für die Nutzung von automatisierter Fertigungstechnik erschlossen. Der zunehmende Einsatz sogenannter Rapid-Manufacturing-Technologien wird neben oder gerade aufgrund additiver Verfahren weiterhin auch den Einsatz von Kleinstbearbeitungsmaschinen (abtragend oder Hybridmaschinensysteme) auf und abseits des industriellen Fertigungsumfeldes fördern. Die Untersuchung der Maschinenpräzision bedeutet aufgrund des geringen Bearbeitungsraumes eine große Herausforderung an die eingesetzten direkten und indirekten Messverfahren.   With the establishment of small machine tools in dental technology, a new market and user community have been developed for the use of automated manufacturing technology. The increasing use of so-called rapid manufacturing technologies will further the use of micro machine tools among or because of additive processes in and around the industrial production environment. The examination of machining quality and machine precision is a major challenge for the direct and indirect measurement methods being used because of the limited working space of micro machine tools.

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Carreira, Pedro, Fábio Cerejo, Nuno Alves e Maria Teresa Vieira. "In Search of the Optimal Conditions to Process Shape Memory Alloys (NiTi) Using Fused Filament Fabrication (FFF)". Materials 13, n. 21 (22 ottobre 2020): 4718. http://dx.doi.org/10.3390/ma13214718.

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This research was performed so as to investigate the additive manufacturing of NiTi shape memory alloys, which is associated with direct processes, such as selective laser melting. In addition to its expensive production costs, NiTi readily undergoes chemical and phase modifications, mainly as a result of Ni loss during processing as a result of high temperatures. This research explores the potential usefulness of NiTi as well as its limitations using indirect additive processes, such as fused filament fabrication (FFF). The first step was to evaluate the NiTi critical powder volume content (CPVC) needed to process high-quality filaments (via extrusion). A typical 3D printer can build a selected part/system/device layer-by-layer from the filaments, followed by debinding and sintering (SDS), in order to generate a near-net-shape object. The mixing, extruding (filament), printing (shaping), debinding, and sintering steps were extensively studied in order to optimize their parameters. Moreover, for the sintering step, two main targets should be met, namely: the reduction of contamination during the process in order to avoid the formation of secondary phases, and the decrease in sintering temperature, which also contributes to reducing the production costs. This study aims to demonstrate the possibility of using FFF as an additive manufacturing technology for processing NiTi.

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Pugalendhi, Arivazhagan, Rajesh Ranganathan, Narendran Venkatapathy, Kalpana Narendran e Parag K. Shah. "Design and development of model eye for retina laser by using additive manufacturing". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 235, n. 1 (28 settembre 2020): 89–98. http://dx.doi.org/10.1177/0954411920960548.

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Surgical skill of the surgeon can be improved by surgical simulation. Especially in ophthalmology, it is impossible to use real human/non-human primate eyes for ophthalmology surgery practice. However, surgical practice is most important for ophthalmologist. The retina laser surgery is one of the ophthalmology surgeries and it requires more surgical practice for surgeons to use the laser beam precisely to coagulate and fuse small areas of tissue. Dealing with the prospect of vision reduction or vision loss presents a peculiar problem and that can be highly stressful and frustrating for both doctors and patients. In this regard, training for indirect ophthalmoscopy and retinal photocoagulation is undergone using model eyes instead of real eyes. Properties and functioning of an existing model eye are huge and they differ from real human eye such as casings are completely rigid and focusing of retinal fundus is not completely covered. Therefore, this research concentrates to develop a model eye that assimilates close to the human eye by focussing on the maximum viewing area that is not done at the moment. Finally, the design and development of re-engineered model eye for retina laser is fabricated by additive manufacturing. Compared to existing plastic model eye, viewing area and viewing angle of the re-engineered model eye is increased by 16.66% and 6.14%, respectively. Due to design modifications and elimination of the insert, it can be reduced by 18.99% and 13.95% of height and weight of the top casing respectively. Developed re-engineered model eye will improve the surgical and diagnostic skill of the surgeon and increase their confidence and proficiency. It also augments the effective use of essential ophthalmic instruments. Additionally, it can reduce the surgical error and meet the existing demand of actual eyes for surgical practices.

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Quintana, Hugo Rondon, Saieth Chaves-Pabón e Diego A. Escobar. "Evaluation of a Warm Mix Asphalt Manufactured with Blast Furnace Slag". Modern Applied Science 12, n. 12 (12 novembre 2018): 28. http://dx.doi.org/10.5539/mas.v12n12p28.

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The study evaluated the response under monotonic loading (Marshall and indirect traction) and the resistance to moisture damage and abrasion of a warm mix asphalt (WMA) manufactured with an additive called HUSIL, when the coarse fraction of the aggregate was replaced by a blast furnace slag (BFS). In conclusion, it is reported that the additive is capable of reducing the manufacturing temperature of the asphalt mixture by 30 ° C. Additionally, the BFS can be used as a partial substitute for the coarse fraction of aggregates in WMA, since when replacing it in 21%, the mixture reach a significant increase in stiffness, resistance to moisture damage, and similar resistance to abrasion with respect to the control asphalt mixture.

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Bassoli, E., L. Denti, A. Gatto, G. Spaletta, A. Paderno, N. Zini, A. Parrilli et al. "A combined additive layer manufacturing / indirect replication method to prototype 3D vascular-like structures of soft tissue and endocrine organs". Virtual and Physical Prototyping 7, n. 1 (marzo 2012): 3–11. http://dx.doi.org/10.1080/17452759.2012.668701.

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El Chawich, Ghenwa, Joelle El Hayek, Vincent Rouessac, Didier Cot, Bertrand Rebière, Roland Habchi, Hélène Garay et al. "Design and Manufacturing of Si-Based Non-Oxide Cellular Ceramic Structures through Indirect 3D Printing". Materials 15, n. 2 (8 gennaio 2022): 471. http://dx.doi.org/10.3390/ma15020471.

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Additive manufacturing of Polymer-Derived Ceramics (PDCs) is regarded as a disruptive fabrication process that includes several technologies such as light curing and ink writing. However, 3D printing based on material extrusion is still not fully explored. Here, an indirect 3D printing approach combining Fused Deposition Modeling (FDM) and replica process is demonstrated as a simple and low-cost approach to deliver complex near-net-shaped cellular Si-based non-oxide ceramic architectures while preserving the structure. 3D-Printed honeycomb polylactic acid (PLA) lattices were dip-coated with two preceramic polymers (polyvinylsilazane and allylhydridopolycarbosilane) and then converted by pyrolysis respectively into SiCN and SiC ceramics. All the steps of the process (printing resolution and surface finishing, cross-linking, dip-coating, drying and pyrolysis) were optimized and controlled. Despite some internal and surface defects observed by topography, 3D-printed materials exhibited a retention of the highly porous honeycomb shape after pyrolysis. Weight loss, volume shrinkage, roughness and microstructural evolution with high annealing temperatures are discussed. Our results show that the sacrificial mold-assisted 3D printing is a suitable rapid approach for producing customizable lightweight highly stable Si-based 3D non-oxide ceramics.

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Phull, Gurpreet Singh, Sanjeev Kumar, Ravinderjit Singh Walia e Harpinder Singh. "Copper Electroforming Optimization for Fused Deposition Modeling Produced ABS Components for Indirect Tooling Applications". Journal of Advanced Manufacturing Systems 19, n. 01 (marzo 2020): 15–29. http://dx.doi.org/10.1142/s021968672050002x.

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The market trends from last few decades have increased the pressure on development of the new products in minimum time. This can be supplemented with modification in the manufacturing processes for product development. Since last two decades, additive manufacturing (AM) also known as rapid prototyping has been used to produce components. The present work aims at optimization of thickness of deposition and surface finish of copper on Acrylonitrile Butadiene Styrene (ABS) components produced by Fused Deposition Modeling (FDM), which can be used for indirect tooling. The different process parameters such as Voltage, Concentration of Copper sulfate Solution (CSS) and deposition time are optimized. The experiment reveals that the best process parameters for maximum deposition rate gives a deposition rate of 0.19 mm/h. The surface roughness is found to be minimum at the lower values of the process parameters as 1.87 [Formula: see text]m. It has been observed that voltage (43.2%) and concentration of CSS (48.8%) significantly affect the deposition rate and for surface finish the concentration of CSS (69.59%) is the major contributor. The microstructure study of the deposited copper reveals a variation in the grain size from coarse to fine as the thickness of the deposited layer increases.

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Van Damme, Lana, Emilie Briant, Phillip Blondeel e Sandra Van Vlierberghe. "Indirect versus direct 3D printing of hydrogel scaffolds for adipose tissue regeneration". MRS Advances 5, n. 17 (2020): 855–64. http://dx.doi.org/10.1557/adv.2020.117.

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ABSTRACTThere exists a need for an innovative reconstructive approach for breast reconstruction, tackling current drawbacks and limitations present in the clinic. In this respect, adipose tissue engineering could offer a promising alternative. We have previously shown that methacrylamide-functionalized gelatin scaffolds are suitable to support the adhesion of adipose tissue-derived stem cells as well as their subsequent differentiation into the adipogenic lineage. The current paper aims to compare different techniques to produce such scaffolds including direct versus indirect 3D printing. Extrusion-based (direct) 3D printing was compared to indirect 3D printing exploiting a polylactic acid (PLA) sacrificial mould, thereby focussing on the physico-chemical characteristics of the obtained scaffolds. The results indicate that similar properties can be achieved irrespective of the technique applied. It can therefore be concluded that indirect 3D printing could offer some benefits over direct additive manufacturing (AM) as a more complex design can be created while materials that were previously unsuited for direct printing because of limitations associated with their characteristics (e.g. low viscosity), could potentially be applied as starting materials for indirect 3D printing to generate porous constructs with full control over their design.

Articoli di riviste sul tema "Indirect additive manufacturing"

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