Stereolithographic Additive Manufacturing of Ceramic Components by Using Nanoparticle Paste Feeding

2016 ◽  
Vol 879 ◽  
pp. 2485-2488 ◽  
Author(s):  
Soshu Kirihara
Keyword(s):  
Additive Manufacturing ◽  
Electromagnetic Waves ◽  
Three Dimensional ◽  
Terahertz Frequency ◽  
Solid Layer ◽  
Cross Sectional ◽  
Ceramic Components ◽  
Fine Pattern ◽  
Graphic Software ◽  
2D Images

Titania and alumina photonic crystals were fabricated by using stereolithographic additive manufacturing to control electromagnetic waves in terahertz frequency. Micro ceramic patterns were designed spatially by graphic software. Photosensitive liquid resin with ceramic particles were spread onto a grass substrate by mechanical knife edge, and two dimensional (2D) images were drawn using fine pattern exposing to create a cross sectional solid layer. After stacking these layers, the obtained three dimensional (3D) structures of composite precursors are dewaxed and sintered.

Stereolithographic Additive Manufacturing of Bulky Ceramic Components with Functionally Geometric Micropattern

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000001-000005
Author(s):  
Soshu Kirihara
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Porous Electrodes ◽  
Beam Diameter ◽  
Cross Sectional ◽  
Geometric Patterns ◽  
Artificial Bones ◽  
Cad Cam

Abstract In a stereolithographic additive manufacturing (AM), two dimensional (2D) cross sectional patterns were created through photo polymerization by ultraviolet laser drawing on spread resin paste including ceramic nanoparticles, and three dimensional (3D) composite models were sterically printed by layer lamination through chemical bonding. An automatic collimeter was equipped with the laser scanner to adjust beam diameter. Fine or coarse beams could realize high resolution or wide area drawings, respectively. Metal and ceramic bulky components including dendritic networks were geometrically built by using stereolithographic AM. Geometric patterns with periodic, self-similar, graded and fluctuated arrangements were created by computer aided design, manufacture and evaluation (CAD/CAM/CAE) for effective modulations of energy and material flows through dielectric lattices in photonic crystals, porous electrodes in fuel cells and biological scaffolds in artificial bones.

Scalable submicrometer additive manufacturing

Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 105-109 ◽  
Author(s):  
Sourabh K. Saha ◽  
Dien Wang ◽  
Vu H. Nguyen ◽  
Yina Chang ◽  
James S. Oakdale ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Design Space ◽  
Three Dimensional ◽  
Complex Structures ◽  
Layer By Layer ◽  
Promising Candidate ◽  
Single Digit ◽  
Cross Sectional ◽  
Two Photon ◽  
Nanoscale Features

High-throughput fabrication techniques for generating arbitrarily complex three-dimensional structures with nanoscale features are desirable across a broad range of applications. Two-photon lithography (TPL)–based submicrometer additive manufacturing is a promising candidate to fill this gap. However, the serial point-by-point writing scheme of TPL is too slow for many applications. Attempts at parallelization either do not have submicrometer resolution or cannot pattern complex structures. We overcome these difficulties by spatially and temporally focusing an ultrafast laser to implement a projection-based layer-by-layer parallelization. This increases the throughput up to three orders of magnitude and expands the geometric design space. We demonstrate this by printing, within single-digit millisecond time scales, nanowires with widths smaller than 175 nanometers over an area one million times larger than the cross-sectional area.

Three Dimensional Smart Processing by Ultra Violet Laser Lithography of Ceramic Additive Manufacturing

2018 ◽  
Vol 941 ◽  
pp. 2196-2199 ◽  
Author(s):  
Koki Nonaka ◽  
Soshu Kirihara
Keyword(s):  
Additive Manufacturing ◽  
Three Dimensional ◽  
Ultra Violet ◽  
Three Dimensional Printing ◽  
Laser Lithography ◽  
Single Process ◽  
Ceramic Components ◽  
Dimensional Printing

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.

Bead Modelling and Deposition Path Planning in Wire Arc Additive Manufacturing of Three Dimensional Parts

2019 ◽  
Vol 969 ◽  
pp. 582-588 ◽  
Author(s):  
Ashish Kumar ◽  
Kuntal Maji
Keyword(s):  
Additive Manufacturing ◽  
Three Dimensional ◽  
Bead Geometry ◽  
Post Processing ◽  
Bead Width ◽  
Cross Sectional ◽  
Current Electrode ◽  
Wire Material ◽  
Single Bead ◽  
Wire Arc Additive Manufacturing

This paper presents investigations on the manufacturing of three-dimensional functional metallic parts through melting and deposition of stainless steel 430L wire material by a metal inert gas welding technique. Experiments were performed on wire arc additive manufacturing following face centered composite design of experiments considering voltage, current, electrode wire material feed rate and welding speed as inputs for modeling single bead geometry in terms of bead width, height, and cross-sectional area. Response surface models were built using the collected experimental data. Performance of the models in predicting the responses was found satisfactory. Models of single bead geometry were employed to calculate void and post-processing in fabricating three-dimensional parts following raster scanning deposition of multiple layers considering the different degree of overlapping and build directions. The theoretically estimated values of void and post-processing were verified through fabrications of two three-dimensional shapes. It was shown that the void and post-processing could be controlled by suitable selection of process parameters, the degree of overlapping between two beads and build direction.

scholarly journals Hybrid additive manufacturing of precision engineered ceramic components

2019 ◽  
Vol 25 (6) ◽  
pp. 1061-1068
Author(s):  
Jack Hinton ◽  
Dejan Basu ◽  
Maria Mirgkizoudi ◽  
David Flynn ◽  
Russell Harris ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Bending Strength ◽  
Three Dimensional ◽  
Digital Fabrication ◽  
Polymer Support ◽  
Content Type ◽  
Novel Approach ◽  
Ceramic Components ◽  
Subtractive Manufacturing ◽  
Machining Operations

Purpose The purpose of this paper is to develop a hybrid additive/subtractive manufacturing platform for the production of high density ceramic components. Design/methodology/approach Fabrication of near-net shape components is achieved using 96 per cent Al3O2 ceramic paste extrusion and a planarizing machining operations. Sacrificial polymer support can be used to aid the creation of overhanging or internal features. Post-processing using a variety of machining operations improves tolerances and fidelity between the component and CAD model while reducing defects. Findings This resultant three-dimensional monolithic ceramic components demonstrated post sintering tolerances of ±100 µm, surface roughness’s of ∼1 µm Ra, densities in excess of 99.7 per cent and three-point bending strength of 221 MPa. Originality/value This method represents a novel approach for the digital fabrication of ceramic components, which provides improved manufacturing tolerances, part quality and capability over existing additive manufacturing approaches.

scholarly journals Phase-field modeling of grain evolutions in additive manufacturing from nucleation, growth, to coarsening

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Min Yang ◽  
Lu Wang ◽  
Wentao Yan
Keyword(s):  
Additive Manufacturing ◽  
Phase Field ◽  
Field Model ◽  
Three Dimensional ◽  
Phase Field Model ◽  
Nucleation Theory ◽  
Experimental Result ◽  
Classical Nucleation Theory ◽  
Validation Experiment ◽  
Powder Particles

AbstractA three-dimensional phase-field model is developed to simulate grain evolutions during powder-bed-fusion (PBF) additive manufacturing, while the physically-informed temperature profile is implemented from a thermal-fluid flow model. The phase-field model incorporates a nucleation model based on classical nucleation theory, as well as the initial grain structures of powder particles and substrate. The grain evolutions during the three-layer three-track PBF process are comprehensively reproduced, including grain nucleation and growth in molten pools, epitaxial growth from powder particles, substrate and previous tracks, grain re-melting and re-growth in overlapping zones, and grain coarsening in heat-affected zones. A validation experiment has been carried out, showing that the simulation results are consistent with the experimental results in the molten pool and grain morphologies. Furthermore, the grain refinement by adding nanoparticles is preliminarily reproduced and compared against the experimental result in literature.

scholarly journals Accuracy and Reproducibility of Facial Measurements of Digital Photographs and Wrapped Cone Beam Computed Tomography (CBCT) Photographs

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 757
Author(s):  
Maged Sultan Alhammadi ◽  
Abeer Abdulkareem Al-mashraqi ◽  
Rayid Hussain Alnami ◽  
Nawaf Mohammad Ashqar ◽  
Omar Hassan Alamir ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam Computed Tomography ◽  
High Reliability ◽  
Three Dimensional ◽  
Cone Beam ◽  
Cross Sectional ◽  
Facial Profile ◽  
Digital Photographs ◽  
Gonial Angle

The study sought to assess whether the soft tissue facial profile measurements of direct Cone Beam Computed Tomography (CBCT) and wrapped CBCT images of non-standardized facial photographs are accurate compared to the standardized digital photographs. In this cross-sectional study, 60 patients with an age range of 18–30 years, who were indicated for CBCT, were enrolled. Two facial photographs were taken per patient: standardized and random (non-standardized). The non-standardized ones were wrapped with the CBCT images. The most used soft tissue facial profile landmarks/parameters (linear and angular) were measured on direct soft tissue three-dimensional (3D) images and on the photographs wrapped over the 3D-CBCT images, and then compared to the standardized photographs. The reliability analysis was performed using concordance correlation coefficients (CCC) and depicted graphically using Bland–Altman plots. Most of the linear and angular measurements showed high reliability (0.91 to 0.998). Nevertheless, four soft tissue measurements were unreliable; namely, posterior gonial angle (0.085 and 0.11 for wrapped and direct CBCT soft tissue, respectively), mandibular plane angle (0.006 and 0.0016 for wrapped and direct CBCT soft tissue, respectively), posterior facial height (0.63 and 0.62 for wrapped and direct CBCT soft tissue, respectively) and total soft tissue facial convexity (0.52 for both wrapped and direct CBCT soft tissue, respectively). The soft tissue facial profile measurements from either the direct 3D-CBCT images or the wrapped CBCT images of non-standardized frontal photographs were accurate, and can be used to analyze most of the soft tissue facial profile measurements.

scholarly journals A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

2021 ◽  
Vol 11 (8) ◽  
pp. 3404
Author(s):  
Majid Hejazian ◽  
Eugeniu Balaur ◽  
Brian Abbey
Keyword(s):  
Molecular Dynamics ◽  
Flow Rate ◽  
Numerical Study ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Liquid Jets ◽  
Mixing Efficiency ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

scholarly journals Efficient 3D printing via photooxidation of ketocoumarin based photopolymerization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyu Zhao ◽  
Ye Zhao ◽  
Ming-De Li ◽  
Zhong’an Li ◽  
Haiyan Peng ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Visible Light ◽  
Light Exposure ◽  
Three Dimensional ◽  
3D Printer ◽  
Light Penetration ◽  
Viable Solution

AbstractPhotopolymerization-based three-dimensional (3D) printing can enable customized manufacturing that is difficult to achieve through other traditional means. Nevertheless, it remains challenging to achieve efficient 3D printing due to the compromise between print speed and resolution. Herein, we report an efficient 3D printing approach based on the photooxidation of ketocoumarin that functions as the photosensitizer during photopolymerization, which can simultaneously deliver high print speed (5.1 cm h−1) and high print resolution (23 μm) on a common 3D printer. Mechanistically, the initiating radical and deethylated ketocoumarin are both generated upon visible light exposure, with the former giving rise to rapid photopolymerization and high print speed while the latter ensuring high print resolution by confining the light penetration. By comparison, the printed feature is hard to identify when the ketocoumarin encounters photoreduction due to the increased lateral photopolymerization. The proposed approach here provides a viable solution towards efficient additive manufacturing by controlling the photoreaction of photosensitizers during photopolymerization.

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