Additive manufacturing of biologically-inspired materials

2016 ◽  
Vol 45 (2) ◽  
pp. 359-376 ◽  
Author(s):  
André R. Studart

Analogous to the layer-by-layer and site-specific deposition of building blocks carried by living organisms during biomineralization (left), additive manufacturing technologies offer a compelling route for the fabrication of bioinspired heterogeneous architectures for next generation composite materials (right).

2021 ◽  
Vol 1 ◽  
pp. 231-240
Author(s):  
Laura Wirths ◽  
Matthias Bleckmann ◽  
Kristin Paetzold

AbstractAdditive Manufacturing technologies are based on a layer-by-layer build-up. This offers the possibility to design complex geometries or to integrate functionalities in the part. Nevertheless, limitations given by the manufacturing process apply to the geometric design freedom. These limitations are often unknown due to a lack of knowledge of the cause-effect relationships of the process. Currently, this leads to many iterations until the final part fulfils its functionality. Particularly for small batch sizes, producing the part at the first attempt is very important. In this study, a structured approach to reduce the design iterations is presented. Therefore, the cause-effect relationships are systematically established and analysed in detail. Based on this knowledge, design guidelines can be derived. These guidelines consider process limitations and help to reduce the iterations for the final part production. In order to illustrate the approach, the spare parts production via laser powder bed fusion is used as an example.


2021 ◽  
Vol 14 ◽  
Author(s):  
Aniket Yadav ◽  
Piyush Chohan ◽  
Ranvijay Kumar ◽  
Jasgurpreet Singh Chohan ◽  
Raman Kumar

Background: Additive manufacturing is the most famous technology which requires materials or composites to be fabricated with layer by layer deposition strategy. Due to its lower cost, higher accuracy and less material wastage; this technology is used in almost every sector. But in many applications there is a need to alter the properties of a product in a certain direction with the help of some reinforcements. With the use of reinforcements, composite layers can be fabricated using additive manufacturing technique which will enhance the directional properties. A novel apparatus is designed to spray the reinforcement material into the printed structures in a very neat and precise manner. This spray nozzle is fully automated, which works according to tool-paths generated by slicing software. The alternate deposition of layers of reinforcement and build materials helped to fabricate customized composite products. Objective: The objective of present study is to design and analyze the working principle of novel technique which has been developed to fabricate composite materials using additive manufacturing. The apparatus is numerically controlled by computer according to CAD data which facilitates the deposition of alternate layers of reinforcement and matrix material. The major challenges during the design process and function of each component has been explored. Methods: The design process is initiated after comprehensive literature review performed to study previous composite manufacturing processes. The recent patents published by different patent offices of the world are studied in detail and analysis has been used to design a low cost composite fabrication apparatus. A liquid dispensing device comprises a storage tank attached with a pump and microprocessor. The microprocessor receives the signal from the computer as per tool paths generated by slicing software which decides the spray of reinforcements on polymer layers. The spraying apparatus moves in coordination with the primary nozzle of the Fused Filament Fabrication process. Results: The hybridization of Fused Filament Fabrication [process with metal spray process has been successfully performed. The apparatus facilitates the fabrication of low cost composite materials along with flexibility of complete customization of composite manufacturing process. The anisotropic behaviour of products can be easily controlled and managed during fabrication which can be used for different applications.


2021 ◽  
Author(s):  
Mevlüt Yunus Kayacan ◽  
Nihat Yılmaz

Abstract Among additive manufacturing technologies, Laser Powder Bed Fusion (L-PBF) is considered the most widespread layer-by-layer process. Although the L-PBF, which is also called as SLM method, has many advantages, several challenging problems must be overcome, including part positioning issues. In this study, the effect of part positioning on the microstructure of the part in the L-PBF method was investigated. Five Ti6Al4V samples were printed in different positions on the building platform and investigated with the aid of temperature, porosity, microstructure and hardness evaluations. In this study, martensitic needles were detected within the microstructure of Ti6Al4V samples. Furthermore, some twins were noticed on primary martensitic lines and the agglomeration of β precipitates was observed in vanadium rich areas. The positioning conditions of samples were revealed to have a strong effect on temperature gradients and on the average size of martensitic lines. Besides, different hardness values were attained depending on sample positioning conditions. As a major result, cooling rates were found related to positions of samples and the location of point on the samples. Higher cooling rates and repetitive cooling cycles resulted in microstructures becoming finer and harder.


2021 ◽  
Author(s):  
Yuan Yao ◽  
Cheng Ding ◽  
Mohamed Aburaia ◽  
Maximilian Lackner ◽  
Lanlan He

Abstract The Fused Filament Fabrication process is the most used additive manufacturing process due to its simplicity and low operating costs. In this process, a thermoplastic filament is led through an extruder, melted, and applied to a building platform by the axial movements of an automated Cartesian system in such a way that a three-dimensional object is created layer by layer. Compared to other additive manufacturing technologies, the components produced have mechanical limitations and are often not suitable for functional applications. To reduce the anisotropy of mechanical strength in fused filament fabrication (FFF), this paper proposes a 3D weaving deposit path planning method that utilizes a 5-layer repetitive structure to achieve interlocking and embedding between neighbor slicing planes to improve the mechanical linkage within the layers. The developed algorithm extends the weaving path as an infill pattern to fill different structures and makes this process feasible on a standard three-axis 3D printer. Compared with 3D weaving printed parts by layer-to-layer deposit, the anisotropy of mechanical properties inside layers is significantly reduced to 10.21% and 0.98%.


2021 ◽  
Vol 12 (3) ◽  
pp. 3513-3521

Additive manufacturing is the term that uses the CAD data to build components layer by layer; it is also termed layered manufacturing or 3D printing. The major advantage of additive manufacturing is the capability of building components without the use of molds or tools. Five major categories of AM processes include Powder Bed Fusion (PBF), Direct Energy Deposition (DED), Material Jetting (MJ), Binder Jetting (BJ), and Sheet Lamination (SL). The sensor may be defined as a device that responds to a physical stimulus and transmits a resulting impulse. Sensor technology has been widely adopted in advanced manufacturing, aerospace, biomedical and robotic applications. Commonly used sensors are temperature sensors, strain sensors, biosensors, environmental sensors, and wearable sensors, etc. Additive manufacturing technologies can fabricate sensors and microfluidic devices with less labor. This paper focuses on various sensors developed by additive manufacturing processes, and their practical application for the particular purpose is reviewed.


2021 ◽  
Author(s):  
Florian Sous ◽  
Tim Herrig ◽  
Thomas Bergs ◽  
Florian Karges ◽  
Nicole Feiling ◽  
...  

Abstract Due to more freedom in design and flexibility in production, parts produced by additive manufacturing technologies (AM) offer a huge potential for the manufacture of turbomachinery components. Because of the layer by layer built structure, internal defects like cracks or gaseous pores can occur. These defects considerably reduce the mechanical properties and increase the importance of quality control, especially in the field of turbomachinery. Therefore, in this study, an electrochemical defect analysis (EC-D) of additive manufactured components is introduced, performed and validated in comparison to a nondestructive X-ray testing of the same part. A test rig was developed, which allows an alternation between electrochemical machining and subsequent optical documentation of each removed layer. The documentation of the surface and the macroscopic defects in the AM-parts are captured by an integrated camera system.


Author(s):  
Prashanth Ravi ◽  
Panos S. Shiakolas ◽  
Tre Welch ◽  
Tushar Saini ◽  
Kristine Guleserian ◽  
...  

Currently, there is a major shift in medical device fabrication research towards layer-by-layer additive manufacturing technologies; mainly owing to the relatively quick transition from a solid model (.STL file) to an actual prototype. The current manuscript introduces a Custom Multi-Modality 3D Bioprinter (CMMB) developed in-house, combining the Fused Filament Fabrication (FFF), Photo Polymerization (PP), Viscous Extrusion (VE), and Inkjet (IJ) printing technologies onto a single additive manufacturing platform. Methodologies to address limitation in the ability to customize construct properties layer-by-layer and to incorporate multiple materials in a single construct have been evaluated using open source 3D printing softwares Slic3r and Repetier-Host. Such customization empowers the user to fabricate constructs with tailorable anisotropic properties by combining different print technologies and materials. To this end, procedures which allow the integration of more than one distinct modality of the CMMB during a single print session were developed and evaluated, and are discussed. The current setup of the CMMB provides the capability to fabricate personalized medical devices using patient data from an MRI or a CT scan. Initial experiments and fabricated constructs demonstrate the potential of the CMMB for research in diverse application areas within biomedical engineering.


Author(s):  
Philipp Fiedler ◽  
Sebastian Stelzer ◽  
Nikolaus Milaev ◽  
Robert Richter ◽  
Frank Kaulfus ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4510
Author(s):  
Martyna Adach ◽  
Paweł Sokołowski ◽  
Tomasz Piwowarczyk ◽  
Krzysztof Nowak

Multi Jet Fusion (MJF) is one of the newest additive manufacturing technologies for polymer powders, introduced in recent years. This fully industrial technology is gaining big interest as it allows fast, layer-by-layer, printing process, short production cycle, and very high printing resolution. In this paper, twelve thin-walled, spherical PA12 prints were studied in terms of geometry, dimensional accuracy, and fracture surface characteristics. The various characteristic features for MJF prints were observed here for parts produced according to four various print orientations and having different thicknesses, i.e., 1, 2 or 3 mm. The study showed that MJF technology can print such difficult shapes. However, the set of parameters allowing producing parts with highest geometrical and dimensional accuracy causes at the same time some microstructural issues, like great interlayer porosity or high number of non-processed powder particles embedded in the print structure.


Author(s):  
Mikhail Osanov ◽  
James K. Guest

The rapid advance of additive manufacturing technologies has provided new opportunities for creating complex structural shapes. In order to fully exploit these opportunities, however, engineers must re-think the design process and leverage these new capabilities while respecting manufacturing constraints inherent in various processes. Topology optimization, as a free-from design tool, is a potentially powerful approach to addressing this design challenge provided the manufacturing process is properly accounted for. This work examines geometric constraints related to feature size and the layer-by-layer nature of the manufacturing process. A simple modification to the Heaviside Projection Method, an approach for naturally achieving geometric constraints in topology optimization, is proposed and demonstrated to have clear, understandable impact on three-dimensional optimized beam designs.


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