scholarly journals Rapid, continuous additive manufacturing by volumetric polymerization inhibition patterning

2019 ◽  
Vol 5 (1) ◽  
pp. eaau8723 ◽  
Author(s):  
Martin P. de Beer ◽  
Harry L. van der Laan ◽  
Megan A. Cole ◽  
Riley J. Whelan ◽  
Mark A. Burns ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Smooth Surfaces ◽  
Single Exposure ◽  
Novel Method ◽  
Acrylate Resin ◽  
Irradiation Wavelength

Contemporary, layer-wise additive manufacturing approaches afford sluggish object fabrication rates and often yield parts with ridged surfaces; in contrast, continuous stereolithographic printing overcomes the layer-wise operation of conventional devices, greatly increasing achievable print speeds and generating objects with smooth surfaces. We demonstrate a novel method for rapid and continuous stereolithographic additive manufacturing by using two-color irradiation of (meth)acrylate resin formulations containing complementary photoinitiator and photoinhibitor species. In this approach, photopatterned polymerization inhibition volumes generated by irradiation at one wavelength spatially confine the region photopolymerized by a second concurrent irradiation wavelength. Moreover, the inhibition volumes created using this method enable localized control of the polymerized region thickness to effect single-exposure, topographical patterning.

Micromachined Ultrasonic Print-Head for Deposition of High-Viscosity Materials

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
J. Mark Meacham ◽  
Amanda O’Rourke ◽  
Yong Yang ◽  
Andrei G. Fedorov ◽  
F. Levent Degertekin ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Three Dimensional ◽  
High Viscosity ◽  
The Novel ◽  
Glycerol Water ◽  
Print Head ◽  
Cavity Resonances ◽  
Allowable Range ◽  
Novel Method ◽  
Manufacturing Techniques

The recent application of inkjet printing to fabrication of three-dimensional, multilayer and multimaterial parts has tested the limits of conventional printing-based additive manufacturing techniques. The novel method presented here, termed as additive manufacturing via microarray deposition (AMMD), expands the allowable range of physical properties of printed fluids to include important, high-viscosity production materials (e.g., polyurethane resins). AMMD relies on a piezoelectrically driven ultrasonic print-head that generates continuous streams of droplets from 45 μm orifices while operating in the 0.5–3.0 MHz frequency range. The device is composed of a bulk ceramic piezoelectric transducer for ultrasound generation, a reservoir for the material to be printed, and a silicon micromachined array of liquid horn structures, which make up the ejection nozzles. Unique to this new printing technique are the high frequency of operation, use of fluid cavity resonances to assist ejection, and acoustic wave focusing to generate the pressure gradient required to form and eject droplets. We present the initial characterization of a micromachined print-head for deposition of fluids that cannot be used with conventional printing-based rapid prototyping techniques. Glycerol-water mixtures with a range of properties (surface tensions of ∼58–73 mN/m and viscosities of 0.7–380 mN s/m2) were used as representative printing fluids for most investigations. Sustained ejection was observed in all cases. In addition, successful ejection of a urethane-based photopolymer resin (surface tension of ∼25–30 mN/m and viscosity of 900–3000 mN s/m2) was achieved in short duration bursts. Peaks in the ejection quality were found to correspond to predicted device resonances. Based on these results, we have demonstrated the printing of fluids that fall well outside of the accepted range for the previously introduced printing indicator. The micromachined ultrasonic print-head achieves sustained printing of fluids up to 380 mN s/m2, far above the typical printable range.

A Novel Transition Region Representation for Additive Manufacturing for Graded Materials, Structures and Tolerances

2017 ◽  
Author(s):  
Gaurav Ameta ◽  
Paul Witherell
Keyword(s):  
Additive Manufacturing ◽  
Transition Region ◽  
Heterogeneous Materials ◽  
Functionally Graded ◽  
Material Distribution ◽  
Graded Materials ◽  
Explicit Material ◽  
Novel Method ◽  
Multiple Material ◽  
Region Representation

Additive manufacturing (AM) has enabled control over heterogeneous materials in ways that were not previously possible. This paper presents a novel method for representing and communicating heterogeneous materials based structures that include tolerancing of geometry and material together. AM has expanded design possibilities to include specified material heterogeneities, including functionally graded materials. The aim of the paper is to propose a means to specify nominal materials and allowable material variations in parts, including (a) explicit material transitions and (b) functional transitions to support single and multiple material behaviors. The transition region combines bounded regions (volumes and surfaces) and material distribution equations. Tolerancing is defined at two levels, that of the geometry including bounded regions and that of the materials. Material tolerances are defined as allowable material variations from nominal material fractions within a unit volume at a given location computed using material distribution equations. The method is described thorough several case studies of abrupt transitions, lattice based transitions, and multi-material transitions.

Novel Method for Making Biomedical Segregation-Free Ti-30Ta Alloy Spherical Powder for Additive Manufacturing

JOM ◽  
2018 ◽  
Vol 70 (3) ◽  
pp. 364-369 ◽  
Author(s):  
Yang Xia ◽  
Zhigang Zak Fang ◽  
Pei Sun ◽  
Ying Zhang ◽  
Jun Zhu
Keyword(s):  
Additive Manufacturing ◽  
Spherical Powder ◽  
Novel Method

scholarly journals A Novel Method for Additive Manufacturing of Complex Shape Curved Parts by Using Variable Height Layers

2021 ◽  
Author(s):  
Matthieu Rauch ◽  
Jorge Piedra Dorado ◽  
Jean-Yves Hascoet ◽  
Guillaume Ruckert
Keyword(s):  
Additive Manufacturing ◽  
Complex Shape ◽  
Novel Method

scholarly journals Additive Manufacturing: A Novel Method for Developing an Acoustic Panel Made of Natural Fiber-Reinforced Composites with Enhanced Mechanical and Acoustical Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Vignesh Sekar ◽  
Mohammad Hosseini Fouladi ◽  
Satesh Narayana Namasivayam ◽  
Sivakumar Sivanesan
Keyword(s):  
Additive Manufacturing ◽  
Natural Fiber ◽  
Agricultural Waste ◽  
Natural Fibers ◽  
Poly Lactic Acid ◽  
Synthetic Fibers ◽  
Acoustical Properties ◽  
Biodegradable Composite ◽  
Novel Method ◽  
Almost All

Natural fibers and their composites are being widely used in almost all the applications in this modern era. However, the properties of natural fibers have to be enhanced in order to compete with synthetic fibers. This review paper opens up additive manufacturing, as a novel method for developing an acoustic panel using natural fiber composites with enhanced mechanical and acoustical properties. This approach will help to replace synthetic-based acoustic absorbers with biodegradable composite panels in acoustic applications. This review also covers, poly(lactic acid) as a polymer matrix and its advantages, the available variety of natural fibers as reinforcement in terms of mechanical and acoustical properties. The natural fiber-based filaments used in additive manufacturing and acoustic panels made from the available natural fibers are also elaborated here. This review shows the importance of additive manufacturing and its application to develop novel acoustic panels made of agricultural waste.

Roughness evaluation of very smooth surfaces using a novel method of scatter measurement

2012 ◽  
Author(s):  
Romuald Synak ◽  
Wlodzimierz Lipinski ◽  
Marcin Pawelczak
Keyword(s):  
Smooth Surfaces ◽  
Novel Method ◽  
Roughness Evaluation

3-D Antenna Structures Using Novel Direct-Write Additive Manufacturing Method

2015 ◽  
Author(s):  
Md Taibur Rahman ◽  
Rahul Panat ◽  
Deuk Heo
Keyword(s):  
Additive Manufacturing ◽  
Data Transfer ◽  
Direct Write ◽  
Form Complex ◽  
Uv Curable ◽  
Manufacturing Method ◽  
Critical Elements ◽  
New Class ◽  
Novel Method ◽  
Thermal Sintering

Sub-mm wavelength 3-D antennas are emerging as critical elements for ultrafast data transfer for various applications. The inherent 2-D nature of lithographic processes severely limits the available manufacturing routes to fabricate such antennas. In this work, we demonstrate a novel additive manufacturing method to fabricate 3-D metal-dielectric antenna structures at sub-mm length scale. A UV curable dielectric is dispensed from an Aerosol Jet system and instantaneously cured to form complex 3-D shapes. A metal nano particle ink is then dispensed over the 3-D dielectric, also by the Aerosol Jet technique, followed by thermal sintering. This novel method opens up the possibility of fabricating an entirely new class of 3-D antenna structures at sub-mm length scales.

scholarly journals Reconstruction of multispectral images from spectrally coded light fields of flat scenes

2019 ◽  
Vol 86 (12) ◽  
pp. 758-764
Author(s):  
Maximilian Schambach ◽  
Fernando Puente León
Keyword(s):  
Light Field ◽  
Real Life ◽  
Microlens Array ◽  
Light Fields ◽  
Multispectral Images ◽  
Single Exposure ◽  
Line Production ◽  
Reconstruction Quality ◽  
Novel Method ◽  
Production Monitoring

AbstractWe present a novel method to reconstruct multispectral images of flat objects from spectrally coded light fields as taken by an unfocused light field camera with a spectrally coded microlens array. In this sense, the spectrally coded light field camera is used as a multispectral snapshot imager, acquiring a multispectral datacube in a single exposure. The multispectral image, corresponding to the light field’s central view, is reconstructed by shifting the spectrally coded subapertures onto the central view according to their respective disparity. We assume that the disparity of the scene is approximately constant and non-zero. Since the spectral mask is identical for all subapertures, the missing spectral data of the central view will be filled up from the shifted spectrally coded subapertures. We investigate the reconstruction quality for different spectral masks and camera parameter sets optimized for real life applications such as in-line production monitoring for which the constant disparity constraint naturally holds. For synthesized reference scenes, using 16 color channels, we achieve a reconstruction \mathrm{PSNR} of up to 51 dB.

scholarly journals Development of Weather-Resistant 3D Printed Structures by Multi-Material Additive Manufacturing

2020 ◽  
Vol 4 (3) ◽  
pp. 94 ◽  
Author(s):  
Arash Afshar ◽  
Roy Wood
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Structural Integrity ◽  
Low Cost ◽  
Acrylonitrile Butadiene Styrene ◽  
Outdoor Environments ◽  
3D Printed ◽  
Novel Method ◽  
Structural Surface

Additive manufacturing, or 3D printing, has had a big impact on the manufacturing world through its low cost, material recyclability, and fabrication of intricate geometries with a high resolution. Three-dimensionally printed polymer structures in aerospace, marine, construction, and automotive industries are usually intended for service in outdoor environments. During long-term exposures to harsh environmental conditions, the mechanical properties of these structures can be degraded significantly. Developing coating systems for 3D printed parts that protect the structural surface against environmental effects and provide desired surface properties is crucial for the long-term integrity of these structures. In this study, a novel method was presented to create 3D printed structures coated with a weather-resistant material in a single manufacturing operation using multi-material additive manufacturing. One group of specimens was 3D printed from acrylonitrile-butadiene-styrene (ABS) material and the other group was printed from ABS and acrylic-styrene-acrylonitrile (ASA) as a substrate and coating material, respectively. The uncoated ABS specimens suffered significant degradation in the mechanical properties, particularly in the failure strain and toughness, during exposure to UV radiation, moisture, and high temperature. However, the ASA coating preserved the mechanical properties and structural integrity of ABS 3D printed structures in aggressive environments.

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