scholarly journals Additive manufacturing of bone scaffolds

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youwen Yang ◽  
Guoyong Wang ◽  
Huixin Liang ◽  
Chengde Gao ◽  
Shuping Peng ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Coupling Efficiency ◽  
Laser Sintering ◽  
High Heating Rate ◽  
Scaffold Design ◽  
Fused Deposition ◽  
Current Characteristics

Additive manufacturing (AM) can obtain not only customized external shape but also porous internal structure for scaffolds, both of which are of great importance for repairing large segmental bone defects. The scaffold fabrication process generally involves scaffold design, AM, and post-treatments. Thus, this article firstly reviews the state-of-the-art of scaffold design, including computer-aided design, reverse modeling, topology optimization, and mathematical modeling. In addition, the current characteristics of several typical AM techniques, including selective laser sintering, fused deposition modeling (FDM), and electron beam melting (EBM), especially their advantages and limitations are presented. In particular, selective laser sintering is able to obtain scaffolds with nanoscale grains, due to its high heating rate and a short holding time. However, this character usually results in insufficient densification. FDM can fabricate scaffolds with a relative high accuracy of pore structure but with a relative low mechanical strength. EBM with a high beam-material coupling efficiency can process high melting point metals, but it exhibits a low-resolution and poor surface quality. Furthermore, the common post-treatments, with main focus on heat and surface treatments, which are applied to improve the comprehensive performance are also discussed. Finally, this review also discusses the future directions for AM scaffolds for bone tissue engineering.

scholarly journals МЕТОД СОЗДАНИЯ МОДЕЛЕЙ САМОЛЕТОВ С ПОМОЩЬЮ СИСТЕМ CAD/CAM/CAE И АДДИТИВНЫХ ТЕХНОЛОГИЙ

2018 ◽  
pp. 24-34
Author(s):  
Ю. Б. Витязев ◽  
А. Г. Гребеников ◽  
А. М. Гуменный ◽  
А. М. Ивасенко ◽  
А. А. Соболев
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Additive Technologies ◽  
Direct Metal Laser Sintering ◽  
Fused Deposition ◽  
Cad Cam ◽  
Deposition Modeling ◽  
Laser Stereolithography

The analysis of the most applicable in mechanical engineering additive technologies (fused deposition modeling, selective laser sintering, laser stereolithography, direct metal laser sintering) have been performed. Method of creating airplane models using CAD/CAM/CAE systems and additive manufacturing is presented. The results of the application of selective laser sintering and fused deposition modeling for the manufacture of training aircraft models are considered.

Carbon Nanotube Reinforced Fused Deposition Modeling Using Microwave Irradiation

2016 ◽  
Author(s):  
Meng Zhang ◽  
Xiaoxu Song ◽  
Weston Grove ◽  
Emmett Hull ◽  
Z. J. Pei ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Additive Manufacturing ◽  
Microwave Irradiation ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Layer By Layer ◽  
Sem Images ◽  
Fused Deposition ◽  
Deposition Modeling

Additive manufacturing (AM) is a class of manufacturing processes where material is deposited in a layer-by-layer fashion to fabricate a three-dimensional part directly from a computer-aided design model. With a current market share of 44%, thermoplastic-based additive manufacturing such as fused deposition modeling (FDM) is a prevailing technology. A key challenge for AM parts (especially for parts made by FDM) in engineering applications is the weak inter-layer adhesion. The lack of bonding between filaments usually results in delamination and mechanical failure. To address this challenge, this study embedded carbon nanotubes into acrylonitrile butadiene styrene (ABS) thermoplastics via a filament extrusion process. The vigorous response of carbon nanotubes to microwave irradiation, leading to the release of a large amount of heat, is used to melt the ABS thermoplastic matrix adjacent to carbon nanotubes within a very short time period. This treatment is found to enhance the inter-layer adhesion without bulk heating to deform the 3D printed parts. Tensile and flexural tests were performed to evaluation the effects of microwave irradiation on mechanical properties of the specimens made by FDM. Scanning electron microscopic (SEM) images were taken to characterize the fracture surfaces of tensile test specimens. The actual carbon nanotube contents in the filaments were measured by conducting thermogravimetric analysis (TGA). The effects of microwave irradiation on the electrical resistivity of the filament were also reported.

scholarly journals USE OF FUSED DEPOSITION MODELING PROCESS IN INVESTMENT PRECISION CASTING AND RISK OF USING SELECTIVE LASER SINTERING PROCESS

2012 ◽  
pp. 226-230
Author(s):  
SIVADASAN M ◽  
N.K SINGH ◽  
ANOOP KUMAR SOOD
Keyword(s):  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Thermal Response ◽  
Acrylonitrile Butadiene Styrene ◽  
Laser Sintering ◽  
Precision Casting ◽  
Fused Deposition ◽  
Rp Process ◽  
Deposition Modeling ◽  
Metallic Parts

Investment Castings (IC) is one of the most economical ways to produce intricate metallic parts when forging, forming and other casting processes tend to fail. However, high tooling cost and long lead time associated with the fabrication of metal moulds for producing IC wax (sacrificial) patterns result in cost justification problems for customized single casting or small-lot production. Generating pattern using rapid prototyping (RP) process may be one of the feasible alternatives. For this purpose present study assessed the suitability of the fused deposition modeling (FDM) process for creating sacrificial IC patterns by studying FDM fabricated part thermal response at various temperatures. A series of experiments with RP patterns are conducted and a set of test castings are also made in steel for establishing feasibility. The build material used is acrylonitrile butadiene styrene (ABS). As an annexe to this work a concurrent attempt is also made to quantify the risk in using Selective Laser Sintering patterns for Investment Castings. Authors hope this work might establish applicability of ABS in IC and also lead the investigations to theoretically tone down the shell cracking tendency with Selective Laser Sintering patterns when Proprietary Duraform is used as the build material.

CubeSat Fabrication through Additive Manufacturing and Micro-Dispensing

2011 ◽  
Vol 2011 (1) ◽  
pp. 001021-001027 ◽  
Author(s):  
Cassie Gutierrez ◽  
Rudy Salas ◽  
Gustavo Hernandez ◽  
Dan Muse ◽  
Richard Olivas ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Printed Circuit Boards ◽  
Fused Deposition Modeling ◽  
Integrated Approach ◽  
Layer By Layer ◽  
New Paradigm ◽  
Spatial Gradients ◽  
Fused Deposition ◽  
On Demand

Fabricating entire systems with both electrical and mechanical content through on-demand 3D printing is the future for high value manufacturing. In this new paradigm, conformal and complex shapes with a diversity of materials in spatial gradients can be built layer-by-layer using hybrid Additive Manufacturing (AM). A design can be conceived in Computer Aided Design (CAD) and printed on-demand. This new integrated approach enables the fabrication of sophisticated electronics in mechanical structures by avoiding the restrictions of traditional fabrication techniques, which result in stiff, two dimensional printed circuit boards (PCB) fabricated using many disparate and wasteful processes. The integration of Additive Manufacturing (AM) combined with Direct Print (DP) micro-dispensing and robotic pick-and-place for component placement can 1) provide the capability to print-on-demand fabrication, 2) enable the use of micron-resolution cavities for press fitting electronic components and 3) integrate conductive traces for electrical interconnect between components. The fabrication freedom introduced by AM techniques such as stereolithography (SL), ultrasonic consolidation (UC), and fused deposition modeling (FDM) have only recently been explored in the context of electronics integration and 3D packaging. This paper describes a process that provides a novel approach for the fabrication of stiff conformal structures with integrated electronics and describes a prototype demonstration: a volumetrically-efficient sensor and microcontroller subsystem scheduled to launch in a CubeSat designed with the CubeFlow methodology.

Recycling of PA-12 in Additive Manufacturing and the Improvement of its Mechanical Properties

2016 ◽  
Vol 674 ◽  
pp. 9-14 ◽  
Author(s):  
Piret Mägi ◽  
Andres Krumme ◽  
Meelis Pohlak
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Raw Material ◽  
Positive Finding ◽  
Polyamide 12 ◽  
Fused Deposition ◽  
Micro Injection Moulding ◽  
Moulding Machine

This study explores possible ways to make Additive Manufacturing (AM) a cradle-to-cradle process, that is, use the leftover from one process as the raw material for another process. The main goal of this study is to develop a set of new polymeric blends with innovative properties, suitable for using in 3-D printing of prosthetic limbs using Fused Deposition Modeling (FDM) technology. Sustainable acting is achieved by reusing polymeric material left over from Selective Laser Sintering (SLS) processes for making raw material for FDM processes. Test specimens of polyamide 12 (PA-12) in its virgin form and used- , un-sintered form alongside specimens of used PA blended with TPU, aramid, or graphite, were produced in a micro-injection moulding machine and then tested for their mechanical properties. This paper provides information about the differences in mechanical characteristics of these different material blends. An unexpected but positive finding was that the differences between virgin and recycled PA-12 are insignificant. The aforementioned additives influenced PA-12 by producing specimens that responded with predictable characteristics which is a significant accomplishment as it lays the groundwork for the next stages of the project.

scholarly journals Ablative Laser Structuring for Stretchable Multilayer and Multi-Material Electronics and Sensor Systems

Proceedings ◽  
2020 ◽  
Vol 56 (1) ◽  
pp. 21
Author(s):  
Simon P. Stier ◽  
Holger Böse
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Circuit Board ◽  
Circuit Boards ◽  
Thermoplastic Polymers ◽  
Digital Light Processing ◽  
Fused Deposition ◽  
Liquid Silicone

Conventional machining and shaping processes for polymers and elastomers such as injection molding exhibit significant disadvantages, as specific tools have to be manufactured, the method of machining is highly dependent on the material properties, and the cost of automation is usually high. Therefore, additive manufacturing processes (3D printing) have established themselves as an alternative. This eliminates the expensive production of tools and the production is individualized. However, the specific (additive) manufacturing process remains highly dependent on the properties of the material. These processes include selective laser sintering (SLS) for powdered thermoplastic polymers and metals, extrusion such as fused deposition modeling (FDM) for thermoplastic polymers in wire form, or optical curing such as digital light processing (DLP) for liquid resins. Especially for elastomer sensors or circuit boards (structure of several alternately constituted approx. 100 µm-thick elastomer films made with different types of liquid silicone rubber), there is no suitable additive manufacturing process that combines liquid, partly non-transparent source materials, multi-component printing, and very fine layer thicknesses. In order to enable a largely automated, computer-aided manufacturing process, we have developed the concept of ablative multilayer and multi-material laser-assisted manufacturing. Here, the layers (conductive and non-conductive elastomers, as well as metal layers for contacting) are first coated over the entire surface (e.g., spray, dip, or doctor blade coating, as well as galvanic coating) and then selectively removed with a CO2 or fiber laser. These steps are repeated several times to achieve a multi-layer structured design. Is it not only possible to adjust and improve the work previously carried out manually, but also to introduce completely new concepts, such as fine through-plating between the layers to enable much more compact structures to be possible. As an exemplary application, we have used the process for manufacturing a thin and surface solderable pressure sensor and a stretchable circuit board.

scholarly journals Additive Manufacturing: A next gen fabrication

2018 ◽  
Vol 8 (01) ◽  
Author(s):  
Prajakta Subhedar
Keyword(s):  
Rapid Prototyping ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Consumer Products ◽  
Cad Model ◽  
Final Model ◽  
Fused Deposition ◽  
Layer Manufacturing ◽  
Deposition Modeling

A class of technologies referring to Rapid Prototyping (RP) or Additive or Layer Manufacturing or 3D Printing allows designers to quickly create tangible prototype instead of using two dimensional pictures. This technology produces models and prototype parts from 3D CAD model data created from 3D object digitizing systems. Rapid Prototyping forms parts by joining together liquid, powder or sheet materials. Physical models are built using three basic stages: pre-processing, building, post-processing. Pre-processing consists of generation of CAD model, convert into STL format and slice the STL files into cross sectional layers. In building process, construction of model takes place one layer atop another. Post process consists of cleaning and finishing the final model. Common types of Rapid Prototyping technologies popular in industry are: Steriolithography, Fused Deposition Modeling, Selective Laser Sintering, Laminated Object Manufacturing,3 D Printing. The selection of the processes depends upon the material to be cured to build the final model. Rapid Prototyping technologies are used in various industries like Automobiles, Consumer products, Medical, Academics, Aerospace, Government and Military. This poster talks about few challenges to be considered in Rapid Prototyping like shrinkage and distortion of final model, mechanical performance of RP model and limitations to mass quantity. : Layer Manufacturing, CAD Model, STL format, Steriolithography, Fused Deposition Modeling, Selective Laser Sintering.

scholarly journals Investigation of Ceramic Dental Prostheses Based on ZrSiO4-Glass Composites Fabricated by Indirect Additive Manufacturing

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Marlon Wesley Machado Cunico
Keyword(s):  
Additive Manufacturing ◽  
Flexural Strength ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Dental Prosthesis ◽  
Dominant Type ◽  
Glass Composites ◽  
Fused Deposition ◽  
Control Factors ◽  
Computer Aided

Dental prosthesis and restoration technologies have been developed in the past years. Despite the advantages of additive manufacturing, computer-aided design, and computer-aided manufacturing technologies are still the dominant type of method for fabricating prostheses. Therefore, the main goal of this study is to assess the feasibility of using indirect fused deposition modeling to fabricate dental prosthesis made of ZrSiO4-glass composites. To achieve this goal, filaments were filled by 90% of ZrSiO4 and 50 μm glass spheres to fabricate prosthesis. Multivariable approach was applied to evaluate the feasibility of the proposed method. Holding temperature, holding time, heating rate, and cooling rate were considered the control factors, while shrinkage, flexural strength, and process feasibility were the study responses. In addition, the flexural strength of materials was found between 25 and 85 MPa, while shrinkage fluctuated between 10 and 25%.

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