scholarly journals Deposition Thickness Modeling and Parameter Identification for a Spray-Assisted Vacuum Filtration Process in Additive Manufacturing

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
August Mark ◽  
Yunjun Xu ◽  
Jihua Gou
Keyword(s):  
Additive Manufacturing ◽  
Electrical Properties ◽  
Filter Cake ◽  
Optimization Approach ◽  
Unknown Parameters ◽  
Filtration Process ◽  
Nonlinear Constrained Optimization ◽  
Vacuum Filtration ◽  
Materials Used ◽  
Filter Cakes

To enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are oftentimes deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties of the final composite material, the thickness of such nanocomposite layers must be precisely controlled. A thickness model for filter cakes created through spray-assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer dynamics in the spray atomization and vacuum filtration are studied to derive solid mass, water mass, and filter cake thickness differential area models. A two-loop nonlinear constrained optimization approach is used to identify the unknown parameters in the model. Experiments involving depositing carbon nanofibers in a sheet of filter paper are used to measure the ability of the model to mimic the filtration process.

scholarly journals Additive Manufacturing Under Lunar Gravity and Microgravity

2021 ◽  
Vol 33 (2) ◽  
Author(s):  
B. Reitz ◽  
C. Lotz ◽  
N. Gerdes ◽  
S. Linke ◽  
E. Olsen ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Spare Parts ◽  
Manufacturing Processes ◽  
Complex Structures ◽  
Lunar Gravity ◽  
Limited Extent ◽  
Test Environment ◽  
Manufacturing Tests ◽  
Laser Experiments ◽  
Materials Used

AbstractMankind is setting to colonize space, for which the manufacturing of habitats, tools, spare parts and other infrastructure is required. Commercial manufacturing processes are already well engineered under standard conditions on Earth, which means under Earth’s gravity and atmosphere. Based on the literature review, additive manufacturing under lunar and other space gravitational conditions have only been researched to a very limited extent. Especially, additive manufacturing offers many advantages, as it can produce complex structures while saving resources. The materials used do not have to be taken along on the mission, they can even be mined and processed on-site. The Einstein-Elevator offers a unique test environment for experiments under different gravitational conditions. Laser experiments on selectively melting regolith simulant are successfully conducted under lunar gravity and microgravity. The created samples are characterized in terms of their geometry, mass and porosity. These experiments are the first additive manufacturing tests under lunar gravity worldwide.

scholarly journals Study of the Electrical Properties of Aluminate Cement Adhesives for Porcelain Insulators

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2232
Author(s):  
Huiwen Wan ◽  
Zhangyin Hu ◽  
Gang Liu ◽  
Jiadong Xiao
Keyword(s):  
Compressive Strength ◽  
Electrical Properties ◽  
Silica Fume ◽  
Drying Time ◽  
Pore Connectivity ◽  
Cement Based Materials ◽  
Porcelain Insulators ◽  
Materials Used ◽  
The Cost ◽  
Aluminate Cement

Electrical properties are one of the essential parameters of cement-based materials used in suspension porcelain insulators. This paper studied the electrical properties of aluminate cement adhesives (ACA) containing silica fume (SF), as well as their compressive strength and porosity. The results indicated that the addition of silica fume improved the resistivity of ACA under a saturated state (relative humidity is 50%). This was mainly attributed to the decrease of the ACA’s pore connectivity due to the SF’s filling effect. However, the early compressive strength of ACA was slightly reduced by the addition of SF. Under an unsaturated state, the ACA’s resistivity without the SF gradually exceeded that with the SF at the extension of drying time. The nuclear magnetic resonance (NMR) results indicated that the addition of SF content increased the ACA’s porosity; for the tiny pores especially, (the size less than 25 nm), this increased by 3.4%. Meanwhile, the addition of SF increased the tortuosity of the ACA’s conductive channels, which could improve its resistivity. Therefore, SF is recommended to be used in cement-based adhesives on insulators to lower the cost and improve the resistivity.

Perovskite and Spinel Functional Coatings for SOFC Metallic Interconnects

2008 ◽  
Vol 595-598 ◽  
pp. 813-822 ◽  
Author(s):  
Tomasz Brylewski ◽  
Kazimierz Przybylski
Keyword(s):  
Electrical Properties ◽  
Ultrasonic Spray Pyrolysis ◽  
Reaction Products ◽  
Functional Coatings ◽  
Steel Microstructure ◽  
Ultrasonic Spray ◽  
Uncoated Steel ◽  
Materials Used ◽  
Co Precipitation ◽  
Metallic Interconnect

The oxidation kinetics, electrical properties, microstructure and chromium vaporization effects of the oxide products formed on Fe-25 wt.-%Cr steel uncoated and coated with films of (La,Sr)CrO3, (La,Sr)CoO3, (La,Sr)(Co,Fe)O3, Mn1.5Cr1.5O4 and MnCo2O4 in air and the Ar-H2-H2O gas mixture at 1023−1173 K for up to 840 h with regard to their application as SOFC metallic interconnect were investigated. To improve poor electrical conductivity of chromia scales and to suppress chromium vaporization from this scale grown on uncoated steel during oxidation, the perovskite and spinel thick films composed of paste prepared via co-precipitation-calcination and ultrasonic spray pyrolysis methods were applied. Perovskite and spinel coatings decreased the volatilization rate of chromia species in comparison with the value of this parameter corresponding to oxide scales built mainly of chromia formed on uncoated steel. Microstructure investigations by the SEM-EDS method and electrical resistance measurements revealed the significant influence of the formation of multilayer reaction products at the steel/coating interface on the electrical properties of the composite materials used for the construction of the SOFC metallic interconnect.

A NOVEL, SCALABLE PRODUCTION OF MULTIFUNCTIONAL NANOCOMPOSITE POLYMER FILAMENTS FOR ADDITIVE MANUFACTURING

2021 ◽  
Author(s):  
MIA CARROLA ◽  
AMIR ASADI
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Additive Manufacturing ◽  
Aqueous Suspension ◽  
Manufacturing Method ◽  
Nanocomposite Polymer ◽  
Water As Solvent ◽  
Materials Used ◽  
Scalable Production

Though a revolutionary process, additive manufacturing (AM) has left more to be desired from printed parts, specifically, improved interlayer strength and minimal defects such as porosity. To overcome these common issues, nanocomposites have become one of the most popular materials used in AM, with various nanoparticles used to achieve a variety of characteristics. The use of these technologies together allows for both to synergistically enhance the final printed parts by improving the process and products simultaneously. Here, we introduce a novel, scalable technique to coat ABS pellets with cellulose nanocrystal (CNC) bonded carbon nanotubes (CNT), to improve the adhesion between layers as well as the mechanical properties of printed parts. An aqueous suspension of CNT-CNC is used to coat ABS pellets before they are dried and extruded into filament for printing. The filament produced using this manufacturing method showed an increase in tensile and interlayer strength as well as improved thermal conductivity. This process uses water as solvent and pristine nanoparticles without the need for any functionalization or surfactants, promoting its scalability. This process has the potential to be used with various polymers and nanoparticles, which allows the materials to be specifically tailored to the end application, (i.e. strength, conductivity, antibacterial, etc.). These nanocomposite filaments have the potential to revolutionize the way that additive manufacturing is utilized in a variety of industries.

The Impact of Carbon Nanotubes and Graphene on Electronics Industry

2018 ◽  
pp. 2897-2907
Author(s):  
Rafael Vargas-Bernal ◽  
Gabriel Herrera-Pérez ◽  
Margarita Tecpoyotl-Torres
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Integrated Circuits ◽  
Electronics Industry ◽  
Future Trends ◽  
Technology Roadmap ◽  
The World ◽  
Materials Used ◽  
Short Time ◽  
The Impact

Since its discovery in 1991 and 2004, carbon nanotubes (CNTs) by Sumio Iijima, and graphene by Andre Geim and Konstantin Novoselov in 2004, these materials have been extensively studied around the world. Both materials have electronic, thermal, magnetic, optical, chemical, and mechanical extraordinary properties. International Technology Roadmap for Semiconductors (ITRS) has predicted that these nanomaterials are potential replacements of the conventional materials used in the manufacture of integrated circuits. Two of the technological aspects that both materials share and have reduced their extensive use are processing and dispersion required to homogenize the electrical properties of the materials based on them. Fortunately, these problems are being solved thanks to the ongoing investigation, and in a short time the materials used in today's electronics industry will be replaced by devices based on these novel materials. The impact of the applications of both materials in the electronics industry, as well as future trends in the following decades are discussed in this paper.

scholarly journals Comparative study of the flexural properties of ABS, PLA and a PLA–wood composite manufactured through fused filament fabrication

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
J.A. Travieso-Rodriguez ◽  
R. Jerez-Mesa ◽  
Jordi Llumà ◽  
Giovanni Gomez-Gras ◽  
Oriol Casadesus
Keyword(s):  
Additive Manufacturing ◽  
Acrylonitrile Butadiene Styrene ◽  
Nozzle Diameter ◽  
Bending Test ◽  
Mechanical Resistance ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Layer Height ◽  
Maximum Deformation ◽  
Materials Used

Purpose The aim of this paper is to analyze the mechanical properties of acrylonitrile-butadiene-styrene (ABS) parts manufactured through fused filament fabrication and compare these results to analogous ones obtained on polylactic acid (PLA) and PLA–wood specimens to contribute for a wider understanding of the different materials used for additive manufacturing. Design/methodology/approach With that aim, an experimental based on an L27 Taguchi array was used to combine the specific parameters taken into account in the study, namely, layer height, nozzle diameter, infill density, orientation and printing velocity. All samples were subjected to a four-point bending test performed according to the ASTM D6272 standard. Findings Young’s modulus, elastic limit, maximum stress and maximum deformation of every sample were computed and subjected to an analysis of variance. Results prove that layer height and nozzle diameter are the most significant factors that affect the mechanical resistance in pieces generated through additive manufacturing and subjected to bending loads, regardless of the material. Practical implications The best results were obtained by combining a layer height of 0.1 mm and a nozzle diameter of 0.6 mm. The comparison of materials evidenced that PLA and its composite version reinforced with wood particles present more rigidity than ABS, whereas the latter can experience further deflection before break. Originality/value This study is of interest for manufacturers that want to decide which is the best material to be applied for their application, as it derives in a practical technical recommendation of the best parameters that should be selected to treat the material during the fused filament fabrication process.

scholarly journals Mechanical properties comparison of Ti6Al4V produced by different technologies under static load conditions

2019 ◽  
Vol 290 ◽  
pp. 08010
Author(s):  
Karolina Karolewska ◽  
Bogdan Ligaj
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Ti6al4v Alloy ◽  
Direct Metal Laser Sintering ◽  
Static Tests ◽  
Rolling Method ◽  
Manufacturing Techniques ◽  
Materials Used

The most commonly used technology among the additive manufacturing is Direct Metal Laser Sintering (DMLS). This process is based on selective laser sintering (SLS). The method gained its popularity due to the possibility of producing metal parts of any geometry, which would be difficult or impossible to obtain by the use of conventional manufacturing techniques. Materials used in the elements manufacturing process are: titanium alloys (e.g. Ti6Al4V), aluminium alloy AlSi10Mg, etc. Elements printed from Ti6Al4V titanium alloy find their application in many industries. Details produced by additive technology are often used in medicine as skeletal, and dental implants. Another example of the DMLS elements use is the aerospace industry. In this area, the additive manufacturing technology produces, i.a. parts of turbines. In addition to the aerospace and medical industries, DMLS technology is also used in motorsport for exhaust pipes or the gearbox parts. The research objects are samples for static tests. These samples were made of Ti6Al4V alloy by the DMLS method and the rolling method from a drawn rod. The aim of the paper is the mechanical properties comparative analysis of the Ti6Al4V alloy produced by the DMLS method under static loading conditions and microstructure analysis of this material.

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