scholarly journals Three-dimensional printing, muscles, and skeleton: mechanical functions of living wood

2019 ◽  
Vol 70 (14) ◽  
pp. 3453-3466 ◽  
Author(s):  
Bernard Thibaut

AbstractWood is well defined as an engineering material. However, living wood in the tree is often regarded only as a passive skeleton consisting of a sophisticated pipe system for the ascent of sap and a tree-like structure made of a complex material to resist external forces. There are two other active key roles of living wood in the field of biomechanics: (i) additive manufacturing of the whole structure by cell division and expansion, and (ii) a ‘muscle’ function of living fibres or tracheids generating forces at the sapwood periphery. The living skeleton representing most of the sapwood is a mere accumulation of dead tracheids and libriform fibres after their programmed cell death. It keeps a record of the two active roles of living wood in its structure, chemical composition, and state of residual stresses. Models and field experiments define four biomechanical traits based on stem geometry and parameters of wood properties resulting from additive manufacturing and force generation. Geometric parameters resulting from primary and secondary growth play the larger role. Passive wood properties are only secondary parameters, while dissymmetric force generation is key for movement, posture control, and tree reshaping after accidents.

Author(s):  
Antonio Sartal ◽  
Diego Carou ◽  
Rubén Dorado-Vicente ◽  
Lorenzo Mandayo

Our research explores how additive manufacturing can support the food industry in facing its current global challenges. Although information technologies are usually highlighted as the main driver of the Industry 4.0 concept, which was first introduced during the Hannover Fair event in 2011, we posit that additive manufacturing can be the true generator of a sustainable competitive advantage in this sector. This evidence stems from a case study in a plant of one of the world’s largest fishing multinational companies. Our results show how, through robotic claw optimization using three-dimensional printing, we not only reduce the manufacturing costs but also increase the flexibility of the line and reduce time to market. On the one hand, our findings should encourage managers to test this technology at their facilities; on the other hand, policymakers should promote the adoption of additive manufacturing, highlighting the potential of this technology within the Industry 4.0 context.


2019 ◽  
Vol 109 (2) ◽  
pp. 166-173 ◽  
Author(s):  
A.B.V. Pettersson ◽  
M. Salmi ◽  
P. Vallittu ◽  
W. Serlo ◽  
J. Tuomi ◽  
...  

Background and Aims: Additive manufacturing or three-dimensional printing is a novel production methodology for producing patient-specific models, medical aids, tools, and implants. However, the clinical impact of this technology is unknown. In this study, we sought to characterize the clinical adoption of medical additive manufacturing in Finland in 2016–2017. We focused on non-dental usage at university hospitals. Materials and Methods: A questionnaire containing five questions was sent by email to all operative, radiologic, and oncologic departments of all university hospitals in Finland. Respondents who reported extensive use of medical additive manufacturing were contacted with additional, personalized questions. Results: Of the 115 questionnaires sent, 58 received answers. Of the responders, 41% identified as non-users, including all general/gastrointestinal (GI) and vascular surgeons, urologists, and gynecologists; 23% identified as experimenters or previous users; and 36% identified as heavy users. Usage was concentrated around the head area by various specialties (neurosurgical, craniomaxillofacial, ear, nose and throat diseases (ENT), plastic surgery). Applications included repair of cranial vault defects and malformations, surgical oncology, trauma, and cleft palate reconstruction. Some routine usage was also reported in orthopedics. In addition to these patient-specific uses, we identified several off-the-shelf medical components that were produced by additive manufacturing, while some important patient-specific components were produced by traditional methodologies such as milling. Conclusion: During 2016–2017, medical additive manufacturing in Finland was routinely used at university hospitals for several applications in the head area. Outside of this area, usage was much less common. Future research should include all patient-specific products created by a computer-aided design/manufacture workflow from imaging data, instead of concentrating on the production methodology.


2018 ◽  
Vol 3 (2) ◽  
pp. 24-33
Author(s):  
Filipa Pinto de Oliveira

consider to be a synonymous of additive manufacturing has made its way into the medical field, not only manufacturing medical appliances, study models or building prosthetics. The demand for bone substitution surgeries is growing every year, due to the increase in pathologies affecting bone structure (both traumatic and not traumatic). Nowadays with the possibility of three-dimensional printers becoming bioprinters, engineered bone tissue is starting to become a reality. The aim of this paper is to give the reader an overview of the work done in the last few years towards the advance of three-dimensional printing methods for engineered bone tissue. This paper is divided into six parts, an introduction, then presentation and discussion of the various printing methods with special focus on additive manufacturing (AM), then of bioprinting technologies, further directions of these technologies are considered and a conclusion is done.


2019 ◽  
Vol 97 ◽  
pp. 06018 ◽  
Author(s):  
Anastasiia Sharanova ◽  
Maria Dmitrieva

Three-dimensional printing is an innovative digital technology and is one of the most significant achievements in the industrial and technological development of modernity. Digital 3D technologies have reached a colossal level of development over a period of about half a century since their invention. Using 3D printing in the construction of low-rise buildings, it becomes possible to implement almost any ideas and achieve the best architectural expressiveness of objects. The aim of this work is to create cement-based compounds that can be used in additive construction methods. A review of the scientific literature on this topic was carried out, the main components of the mixture were identified, and a series of field experiments were conducted. According to the results of the work, the optimal composition for 3D construction printing was determined.


2018 ◽  
Vol 941 ◽  
pp. 2196-2199 ◽  
Author(s):  
Koki Nonaka ◽  
Soshu Kirihara

Additive manufacturing (AM) and three-dimensional printing (3DP) technologies are being developed for use in manufacturing. In this study, a new AM technology, laser stereo-lithography, that enables to fabricate ceramic components in a single process is developed. This method is demonstrated with alumina under various laser conditions.


2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Christopher B. Williams ◽  
Farrokh Mistree ◽  
David W. Rosen

Many different additive manufacturing (AM) technologies enable the realization of prototypes and fully-functional artifacts. Although very different in solution principle and embodiment, significant functional commonality exists among the technologies. This commonality affords the authors an opportunity to propose a new classification framework for additive manufacturing technologies. Specifically, by following the systematic abstraction approach proposed by the design methodology of Pahl and Beitz, the authors first identify the working principles of each AM process. A morphological matrix is then employed to functionally present these principles such that commonalities between processes can be identified. In addition to using it as a means of classifying existing processes, the authors present the framework as a tool to aid a designer in the conceptual design of new additive manufacturing technologies. The authors close the paper with an example of such an implementation; specifically, the conceptual design of a novel means of obtaining metal artifacts from three-dimensional printing.


CIRP Annals ◽  
1993 ◽  
Vol 42 (1) ◽  
pp. 257-260 ◽  
Author(s):  
Emanuel Sachs ◽  
Michael Cima ◽  
James Cornie ◽  
David Brancazio ◽  
Jim Bredt ◽  
...  

2018 ◽  
Vol 53 (7) ◽  
pp. 873-882 ◽  
Author(s):  
Breno Ferreira Lizardo ◽  
Luciano Machado Gomes Vieira ◽  
Juan Carlos Campos Rubio ◽  
Tulio Hallak Panzera ◽  
João Paulo Davim

Rapid prototyping for material deposition or additive manufacturing has been widely used for short time production of parts with complex geometry in small series. The three-dimensional printing process needs post-processing to improve the strength, stiffness and/or surface finish of the parts. Printed parts in pristine condition are generally very brittle with a porous structure, so infiltrates have been introduced to improve their mechanical and physical characteristics. This work investigates the effect of two infiltrates, epoxy polymer and cyanoacrylate, under a vacuum pressure system on the mechanical properties of powder-based composites made by three-dimensional printing. Samples printed under pristine and infiltrated conditions were tested under tensile, flexural, compressive and impact loadings. The infiltrated samples achieved superior mechanical properties, especially when the epoxy polymer was applied via a vacuum system. The microstructural analysis showed that the infiltrates were not able to penetrate the entire sample, revealing a porous structure in the centre, mainly when the cyanoacrylate was used. The epoxy polymer infiltrate was able to substantially increase the mechanical performance of three-dimensional samples, being a promising material when higher structural requirements are required.


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