11,808 research outputs found
Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review
Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed
Designing Volumetric Truss Structures
We present the first algorithm for designing volumetric Michell Trusses. Our
method uses a parametrization approach to generate trusses made of structural
elements aligned with the primary direction of an object's stress field. Such
trusses exhibit high strength-to-weight ratios. We demonstrate the structural
robustness of our designs via a posteriori physical simulation. We believe our
algorithm serves as an important complement to existing structural optimization
tools and as a novel standalone design tool itself
Digital manufacturing: what are we able to print?
In a rational exercise, in the present paper it is extrapolated how the development of ICTs (information and communication technologies) and the incipient technological development of additive manufacturing has the potential to change our society. In the following, it is analyzing the evolution of man over physical matter and how this has shaped our society. The main milestones or key stages in history that have marked a transcendental change in the human-machine-environment relationship have been identified and consequently have led us to ask ourselves: What is next, how far are we, and what are we capable of printing? In an attempt to identify the current state of the art, highlighting the possibilities those additive technologies can offerPostprint (published version
From 3D Models to 3D Prints: an Overview of the Processing Pipeline
Due to the wide diffusion of 3D printing technologies, geometric algorithms
for Additive Manufacturing are being invented at an impressive speed. Each
single step, in particular along the Process Planning pipeline, can now count
on dozens of methods that prepare the 3D model for fabrication, while analysing
and optimizing geometry and machine instructions for various objectives. This
report provides a classification of this huge state of the art, and elicits the
relation between each single algorithm and a list of desirable objectives
during Process Planning. The objectives themselves are listed and discussed,
along with possible needs for tradeoffs. Additive Manufacturing technologies
are broadly categorized to explicitly relate classes of devices and supported
features. Finally, this report offers an analysis of the state of the art while
discussing open and challenging problems from both an academic and an
industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and
Innovation action; Grant agreement N. 68044
Three-dimensional microfabrication through a multimode optical fiber
Additive manufacturing, also known as 3D printing, is an advanced
manufacturing technique that allows the fabrication of arbitrary macroscopic
and microscopic objects. All 3D printing systems require large optical elements
or nozzles in proximity to the built structure. This prevents their use in
applications in which there is no direct access to the area where the objects
have to be printed. Here, we demonstrate three-dimensional microfabrication
based on two-photon polymerization (TPP) with sub diffraction-limited
resolution through an ultra-thin, 50 mm long printing nozzle of 560 micrometers
in diameter. Using wavefront shaping, femtosecond infrared pulses are focused
and scanned through a multimode optical fiber (MMF) inside a photoresist that
polymerizes via two-photon absorption. We show the construction of arbitrary 3D
structures of 500 nm resolution on the other side of the fiber. To our
knowledge, this is the first demonstration of microfabrication through a
multimode optical fiber. Our work represents a new area which we refer to as
endofabrication
Recommended from our members
Generation of Porous Structures Using Fused Deposition
The Fused Deposition Modeling process uses hardware and software machine-level
language that are very similar to that of a pen-plotter. Consequently, the·use of patterns with
poly-lines as basic geometric features, instead of the current method based on filled polygons
(monolithic models), can increase its efficiency.
In the current study, various toolpath planning methods have been developed to fabricate
porous structures. Computational domain decomposition methods can be applied to the physical
or to slice-level domains to generate structured and unstructured grids. Also, textures can be
created using periodic tiling of the layer with unit cells (squares, honeycombs, etc). Methods
'based on curves include fractal space filling curves and.change of effective road width Within a
layer or within a continuous curve. Individual phases can also be placed in binary compositions.
In present investigation, a custom software has been developed and implemented to
generate build files (SML) and slice files (SSL) for the above-mentioned structures, demonstrating the efficient control ofthe size, shape, and distribution ofporosity.Mechanical Engineerin
Acrylic acid plasma coated 3D Scaffolds for Cartilage tissue engineering applications
Abstract The current generation of tissue engineered additive manufactured scaffolds for cartilage repair shows high potential for growing adult cartilage tissue. This study proposes two surface modification strategies based on non-thermal plasma technology for the modification of poly(ethylene oxide terephthalate/poly(butylene terephthalate) additive manufactured scaffolds to enhance their cell-material interactions. The first, plasma activation in a helium discharge, introduced non-specific polar functionalities. In the second approach, a carboxylic acid plasma polymer coating, using acrylic acid as precursor, was deposited throughout the scaffolds. Both surface modifications were characterized by significant changes in wettability, linked to the incorporation of new oxygen-containing functional groups. Their capacity for chondrogenesis was studied using ATDC5 chondroblasts as a model cell-line. The results demonstrate that the carboxylic acid-rich plasma coating had a positive effect on the generation of the glucoaminoglycans (GAG) matrix and stimulated the migration of cells throughout the scaffold. He plasma activation stimulated the formation of GAGs but did not stimulate the migration of chondroblasts throughout the scaffolds. Both plasma treatments spurred chondrogenesis by favoring GAG deposition. This leads to the overall conclusion that acrylic acid based plasma coatings exhibit potential as a surface modification technique for cartilage tissue engineering applications
Towards a complex geometry manufacturing : A case study on metal 3D printing of topology optimised bicycle parts with lattices
Manufacturing metal parts with complex geometries using conventional methods has proven to be almost impossible due to tooling constraints. Additive Manufacturing (AM) or 3D printing has proven to be a solution for manufacturing such parts since the constraints imposed by traditional manufacturing are not applicable to AM. The research objective is to demonstrate the workflow from design to manufacturing complex geometry parts specifically for AM Selective Laser Melting (SLM) process, it also has its own constraints that are different than traditional manufacturing. AM provides a solution to manufacturing topology optimised complex geometries that cannot be manufactured using conventional methods. In order to demonstrate the possibilities and challenges of producing complex geometries with additive manufacturing, a case study of manufacturing topology optimised bicycle parts has been conducted at the University of Vaasa, Finland using SLM technology, based on the Powder Bed Fusion (PBF) process. The results of this research show that metal 3D printing is an enabler for manufacturing topology optimised complex geometries with challenges such as the need to edit and optimise the automatically-generated supports, and thermal solid support design for anchoring large flat surfaces, and possible boundary shells issues and post-processing planning.©2022 the Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)fi=vertaisarvioitu|en=peerReviewed
- …