A Fast Mask Projection Stereolithography Process for Fabricating Digital Models in Minutes

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Yayue Pan ◽  
Chi Zhou ◽  
Yong Chen
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Thin Layers ◽  
Digital Models ◽  
Projection System ◽  
Order Of Magnitude ◽  
Projection Stereolithography ◽  
Direct Digital Manufacturing ◽  
3D Digital Models

The purpose of this paper is to present a direct digital manufacturing (DDM) process that is an order of magnitude faster than other DDM processes that are currently available. The developed process is based on a mask-image-projection-based stereolithography (MIP-SL) process, in which a digital micromirror device (DMD) controls projection light to selectively cure liquid photopolymer resin. In order to achieve high-speed fabrication, we investigate the bottom-up projection system in the MIP-SL process. A two-way linear motion approach has been developed for the quick spreading of liquid resin into uniform thin layers. The system design and related settings for achieving a fabrication speed of a few seconds per layer are presented. Additionally, the hardware, software, and material setups for fabricating three-dimensional (3D) digital models are presented. Experimental studies using the developed testbed have been performed to verify the effectiveness and efficiency of the presented fast MIP-SL process. The test results illustrate that the newly developed process can build a moderately sized part within minutes instead of hours that are typically required.

Rapid Manufacturing in Minutes: The Development of a Mask Projection Stereolithography Process for High-Speed Fabrication

2012 ◽  
Author(s):  
Yayue Pan ◽  
Chi Zhou ◽  
Yong Chen
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Film Coating ◽  
Thin Layers ◽  
Projection System ◽  
Order Of Magnitude ◽  
Cross Links ◽  
Projection Stereolithography ◽  
Direct Digital Manufacturing

The purpose of this paper is to present a direct digital manufacturing (DDM) process that is an order of magnitude faster than other DDM processes currently available. The developed process is based on a mask-image-projection-based Stereolithography process (MIP-SL), during which a Digital Micromirror Device (DMD) controlled projection light cures and cross-links liquid photopolymer resin. In order to achieve high-speed fabrication, we investigated the bottom-up projection system in the MIP-SL process. A set of techniques including film coating and the combination of two-way linear motions have been developed for the quick spreading of liquid resin into uniform thin layers. The process parameters and related settings to achieve the fabrication speed of a few seconds per layer are presented. Additionally, the hardware, software, and material setups developed for fabricating given three-dimensional (3D) digital models are presented. Experimental studies using the developed testbed have been performed to verify the effectiveness and efficiency of the presented fast MIP-SL process. The test results illustrate that the newly developed process can build a moderately sized part within minutes instead of hours that are typically required.

scholarly journals Investigation of Flow Behavior around Corotating Blades in a Double-Spindle Lawn Mower Deck

2005 ◽  
Vol 2005 (1) ◽  
pp. 77-89 ◽  
Author(s):  
W. Chon ◽  
R. S. Amano
Keyword(s):  
Flow Pattern ◽  
High Speed ◽  
Flow Behavior ◽  
Flow Analysis ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Video Camera ◽  
Sound Level ◽  
Lawn Mower ◽  
Level Meter

When the airflow patterns inside a lawn mower deck are understood, the deck can be redesigned to be efficient and have an increased cutting ability. To learn more, a combination of computational and experimental studies was performed to investigate the effects of blade and housing designs on a flow pattern inside a1.1mwide corotating double-spindle lawn mower deck with side discharge. For the experimental portion of the study, air velocities inside the deck were measured using a laser Doppler velocimetry (LDV) system. A high-speed video camera was used to observe the flow pattern. Furthermore, noise levels were measured using a sound level meter. For the computational fluid dynamics (CFD) work, several arbitrary radial sections of a two-dimensional blade were selected to study flow computations. A three-dimensional, full deck model was also developed for realistic flow analysis. The computational results were then compared with the experimental results.

Numerical and Experimental Investigation of Secondary Flow in a High Speed Compressor Stator

1995 ◽  
Author(s):  
Y. Ohkita ◽  
H. Kodama ◽  
O. Nozaki ◽  
K. Kikuchi ◽  
A. Tamura
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Shear Flow ◽  
Secondary Flow ◽  
Total Pressure ◽  
High Speed ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Performance Recovery

A series of numerical and experimental studies have been conducted to understand the mechanism of loss generation in a high speed compressor stator with inlet radial shear flow over the span. In this study, numerical simulation is extensively used to investigate the complex three-dimensional flow in the cascades and to interpret the phenomena appeared in the high speed compressor tests. It has been shown that the inlet radial shear flow generated by upstream rotor had a significant influence on the stator secondary flow, and consequently on the total pressure loss. Redesign of the stator aiming at the reduction of loss by controlling secondary flow has been carried out and the resultant performance recovery was successfully demonstrated both numerically and experimentally.

Modelling mechanically stable muscle architectures

1992 ◽  
Vol 336 (1277) ◽  
pp. 275-292 ◽  
Keyword(s):  
Pressure Distribution ◽  
Volume Fraction ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Muscle Fibres ◽  
Pressure Measurements ◽  
Muscle Belly ◽  
Longitudinal Plane ◽  
Order Of Magnitude ◽  
Volume Problem

This paper presents a planar architectural model for an activated skeletal muscle, with mechanical equilibrium throughout the muscle belly. The model can predict the shape of the muscle fibres and tendinous sheets as well as the internal pressure distribution in the central longitudinal plane (perpendicular to the tendinous sheets) of uni- and bipennate muscle bellies. Mechanically stable solutions for muscle architectures were calculated by equating the pressure developed by curved muscle fibres with the pressure under a curved tendinous sheet. The pressure distribution under a tendinous sheet is determined by its tension, its curvature and the tensile stress of the attached muscle fibres. Dissections showed a good resemblance of the architecture of embalmed muscles with those from our simulations. Calculated maximum pressures are in the same order of magnitude as pressure measurements from the literature. Our model predicts that intramuscular blood flow can be blocked during sustained contraction, as several experimental studies have indeed demonstrated. The volume fractions of muscle fibres and interfibre space in the muscle belly were also calculated. The planar models predict a too low volume fraction for the muscle fibres (about 45% for the bipennate models with a straight central aponeurosis, and about 60% for the simulated unipennate muscle). It is discussed how, in a real muscle, this volume problem can be solved by a special three-dimensional arrangement of muscle fibres in combination with varying widths of the tendinous sheets.

scholarly journals Promoting a More Interactive Public Archaeology

2015 ◽  
Vol 3 (3) ◽  
pp. 235-248 ◽  
Author(s):  
Bernard K. Means
Keyword(s):  
Narrow Band ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Public Archaeology ◽  
Archaeological Sites ◽  
Digital Models ◽  
The Past ◽  
Fresh Perspective ◽  
Virginia Commonwealth University ◽  
3D Digital Models

AbstractStewards of the tangible past are increasingly embracing technologies that enable digital preservation of rare and fragile finds. The Virtual Curation Laboratory (VCL) at Virginia Commonwealth University (VCU) partners with museums, cultural heritage locations, and collections repositories to create three-dimensional (3D) digital models of artifacts from archaeological sites distributed across the globe. In the VCL, undergraduate VCU students bring a fresh perspective unburdened by archaeological orthodoxy as they use a laser scanner to record artifact details, edit the resulting digital models, and print plastic replicas that are painted to resemble the original items. The 3D digital models and printed replicas allow for new ways of visualizing the past, while preserving the actual artifacts themselves. These forms of archaeological visualization enable the broader public and not just a narrow band of researchers to dynamically and meaningfully interact with rare and fragile objects in ways that would otherwise not be possible, empowering their own contributions to interpreting, understanding, and reimagining the past. We must embrace co-creation through virtual artifact curation and recognize that, while we sacrifice some control over the stories that are told about the past, more stories will be told and shared as pieces of the past become more accessible.

Numerical and Experimental Investigation of Secondary Flow in a High-Speed Compressor Stator

1997 ◽  
Vol 119 (2) ◽  
pp. 169-175
Author(s):  
Y. Ohkita ◽  
H. Kodama ◽  
O. Nozaki ◽  
K. Kikuchi ◽  
A. Tamura
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Shear Flow ◽  
Secondary Flow ◽  
Total Pressure ◽  
High Speed ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Performance Recovery

A series of numerical and experimental studies have been conducted to understand the mechanism of loss generation in a high-speed compressor stator with inlet radial shear flow over the span. In this study, numerical simulation is extensively used to investigate the complex three-dimensional flow in the cascades and to interpret the phenomena that appeared in the high-speed compressor tests. It has been shown that the inlet radial shear flow generated by the upstream rotor had a significant influence on the stator secondary flow, and consequently on the total pressure loss. Redesign of the stator aiming at the reduction of loss by controlling secondary flow has been carried out and the resultant performance recovery was successfully demonstrated both numerically and experimentally.

scholarly journals 3D Printing of Human Microbiome Constituents to Understand Spatial Relationships & Shape Parameters in Bacteriology

2021 ◽  
Vol 83 (3) ◽  
pp. 188-190
Author(s):  
Jacques Izard ◽  
Teklu Kuru Gerbaba ◽  
Shara R. P. Yumul
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Human Microbiome ◽  
Digital Models ◽  
Ecological Relationships ◽  
Wide Range ◽  
3D Printers ◽  
Visuospatial Information ◽  
Aided Design ◽  
3D Digital Models

Effective laboratory and classroom demonstration of microbiome size and shape, diversity, and ecological relationships is hampered by a lack of high-resolution, easy-to-use, readily accessible physical or digital models for use in teaching. Three-dimensional (3D) representations are, overall, more effective in communicating visuospatial information, allowing for a better understanding of concepts not directly observable with the unaided eye. Published morphology descriptions and microscopy images were used as the basis for designing 3D digital models, scaled at 20,000×, using computer-aided design software (CAD) and generating printed models of bacteria on mass-market 3D printers. Sixteen models are presented, including rod-shaped, spiral, flask-like, vibroid, and filamentous bacteria as well as different arrangements of cocci. Identical model scaling enables direct comparison as well as design of a wide range of educational plans.

scholarly journals Three-Dimensional Measurement and Three-Dimensional Printing of Giant Coastal Rocks

2021 ◽  
Vol 10 (6) ◽  
pp. 404
Author(s):  
Zhiyi Gao ◽  
Akio Doi ◽  
Kenji Sakakibara ◽  
Tomonaru Hosokawa ◽  
Masahiro Harata
Keyword(s):  
Effective Means ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Satellite System ◽  
Shape Reconstruction ◽  
3D Measurement ◽  
Digital Models ◽  
Cloud Data ◽  
3D Shape Reconstruction ◽  
3D Digital Models

In recent years, the use of three-dimensional (3D) measurement and printing technologies has become an effective means of analyzing and reproducing both physical and natural objects, regardless of size. However, in some complex environments, such as coastal environments, it is difficult to obtain the required data by conventional measurement methods. In this paper, we describe our efforts to archive and digitally reproduce a giant coastal rock formation known as Sanouiwa, a famous site off the coast of Miyako City, Iwate Prefecture, Japan. We used two different 3D measurement techniques. The first involved taking pictures using a drone-mounted camera, and the second involved the use of global navigation satellite system data. The point cloud data generated from the high-resolution camera images were integrated using 3D shape reconstruction software, and 3D digital models were created for use in tourism promotion and environmental protection awareness initiatives. Finally, we fabricated the 3D digital models of the rocks with 3D printers for use as museum exhibitions, school curriculum materials, and related applications.

High-Speed, High-Resolution 3D Imaging Using Projector Defocusing

2011 ◽  
pp. 121-140
Author(s):  
Song Zhang ◽  
Yuanzheng Gong
Keyword(s):  
High Speed ◽  
3D Imaging ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Projection System ◽  
Digital Fringe Projection ◽  
System Nonlinearity ◽  
Projection Techniques ◽  
Fringe Patterns ◽  
3D Scene

With the advance of software and hardware, three-dimensional (3D) scene digitization becomes increasingly important. Over the years, numerous 3D imaging techniques have been developed. Among these techniques, the methods based on analyzing sinusoidal structured (fringe) patterns stand out due to their achievable speed and resolution. With the development of digital video display technologies, digital fringe projection techniques emerge as a mainstream for 3D imaging. However, developing such a system is not easy especially when an off-the-shelf projector is used. The major challenging problems are: (1) the projection system nonlinearity; (2) the precise synchronization requirement; and (3) the projection system speed limit. This chapter will present an alternative route for 3D imaging while reducing these problems. The fundamentals of the proposed technique will be introduced, the analytical and experimental results will be shown, and its advantages and limitations will be addressed.

Computational Modeling of a Solar Thermoelectric Generator

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Chukwunyere Ofoegbu ◽  
Sandip Mazumder
Keyword(s):  
Solar Energy ◽  
Computational Model ◽  
Peak Power ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Atmospheric Conditions ◽  
Absorber Plate ◽  
Thermoelectric Effects ◽  
Order Of Magnitude ◽  
Solar Thermoelectric Generator

Solar thermoelectric generators (STEGs) convert solar energy to electricity. The solar energy is first used to heat an absorber plate that serves as the high temperature reservoir. Power is generated by connecting the hot reservoir and cold (ambient) reservoirs with a pair of p- and n-doped thermoelectric legs. Experimental studies have shown that the efficiency of a STEG can reach values of about 5% if the entire setup is placed in near-vacuum conditions. However, under atmospheric conditions, the efficiency decreases by more than an order of magnitude, presumably due to heat loss from the absorber plate by natural convection. A coupled fluid–thermal–electric three-dimensional computational model of a STEG is developed with the objective of understanding the various loss mechanisms that contribute to its poor efficiency. The governing equations of mass, momentum, energy, and electric current, with the inclusion of thermoelectric effects, are solved on a mesh with 60,900 cells, and the power generated by the device is predicted. The computational model predicts a temperature difference (ΔT) of 16.5 K, as opposed to the experimentally measured value of 15 K. This corresponds to a peak power of 0.031 W as opposed to the experimentally measured peak power of 0.021 W. When only radiative losses are considered (i.e., perfect vacuum), the ΔT increases drastically to 131.1 K, resulting in peak power of 1.43 W. The predicted peak efficiency of the device was found to be 0.088% as opposed to the measured value of 0.058%.

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