5,375 research outputs found
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Exploring Vacuum Casting Techniques for Micron and Submicron Features
A study of resolution limits in standard rapid prototyping vacuum cast molding processes and
adaptation of this technique to reach submicron accuracy is proposed. Micro-fabrication
technologies are used to fabricate micron and submicron high aspect-ratio patterns on the
original parts. The molding of the original parts is optimized to allow replication of submicron
features. In carefully exploring materials and surface treatments, cast parts are successfully
replicated with submicron and high aspect ratio micron structures. These encouraging results
enable the use of such processes for micro- and nano-systems applications and open the door
to development and production of low cost, high resolution biochips.Mechanical Engineerin
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Prototyping a process-centered environment
This paper describes an experimental system developed and used as a vehicle for prototyping the Arcadia-1 software development environment. Prototyping is viewed as a knowledge acquisition process and is used to reduce risks in software development by gaining rapid feedback about the suitability of a production system before the system is completed. Prototyping a software development environment is particularly important due to the lack of experience with them. There is an acute need to acquire knowledge about user interaction requirements for software environments. These needs are especially important for the Arcadia project, as it is one of the first attempts to construct a process-centered environment. Our prototyping effort addresses questions about effective interaction with a process-centered environment by simulating how Arcadia-1 would interact with users in a representative range of usage scenarios. We built a prototyping system, called PRODUCER, and used it to generate a variety of prototypes simulating user interactions with Arcadia-1 process programs.Experience with PRODUCER indicates that our approach is effective at risk reduction. The prototypes greatly improved communication with our customer. They confirmed some of our design decisions but also redirected our research efforts as a result of unexpected insight. We also found that prototyping usage scenarios provides conceptual guides and design information for process programmers. Most of the benefits of our prototyping effort derive from developing and interacting with usage scenarios, so our approach is generalizable to other prototyping systems. This paper reports on our prototyping approach and our experience in prototyping a process-centered environment
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Microscale Freeform Integration by Directed Self Assembly
Most solid freeform fabrication (SFF) manufacturing processes assemble uniform
components such as powder particles or polymer chains to produce desired geometries. Their
capacity for producing highly functional parts (integrated actuation, sensing, and electronics)
will dramatically increase when multiple materials and functional subcomponents can be
automatically integrated. This paper addresses criteria for a system that integrates multiple
materials and components through computer-controlled self-assembly. It builds complex systems
from layers of self-assembled micro-components. The paper will address implementation
methods, present a concept demonstration, and consider its application to micro-thermoelectric
systems. This manufacturing process can be enhanced further through integration with mature
additive processes.Mechanical Engineerin
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A Film Fabrication Process on Transparent Substrate using Mask Projection Micro-Stereolithography
In this study, a Mask Projection Micro-Stereolithography (MP”SLA) process with the
ability to cure a film of various thicknesses on transparent substrates is presented. Incident
radiation, patterned by a dynamic mask, passes through a transparent substrate to cure
photopolymer resin layers that grow progressively from the substrate surface. When compared
to existing Stereolithography techniques, this technique eliminates the necessity of recoating,
reducing process time and improving accuracy. A film of varying thicknesses can be fabricated
on flat or curved transparent substrates. Models of the optical system and resin cure are
developed and reported. An existing MP”SLA process planning method is being extended to
account for radiation transmission through a substrate. The models are verified using
experiments.Mechanical Engineerin
Toward mass production of microtextured microdevices: linking rapid prototyping with microinjection molding
The possibility of manufacturing textured materials and devices, with surface properties controlled from the design stage, instead of being the result of machining processes
or chemical attacks, is a key factor for the incorporation of advanced functionalities to a wide set of micro and nanosystems. Recently developed high-precision additive manufacturing technologies, together with the use of fractal models linked to computer-aided design tools, allow for a precise definition and control of final surface properties for a wide set of applications, although the production of larger series based on these resources is still an unsolved challenge. However, rapid prototypes, with controlled surface topography, can be used as original masters for obtaining micromold inserts for final large-scale series manufacture of replicas using microinjection molding. In this study, an original procedure is presented, aimed at connecting rapid prototyping with microinjection molding, for the mass production of two different microtextured microsystems, linked to tissue engineering tasks, using different thermoplastics as ultimate materials
Rapid prototyping of multi-scale biomedical microdevices by combining additive manufacturing technologies
The possibility of designing and manufacturing biomedical microdevices with multiple length-scale geometries can help to promote special interactions both with their environment and with surrounding biological systems. These interactions aim to enhance biocompatibility and overall performance by using biomimetic approaches. In this paper, we present a design and manufacturing procedure for obtaining multi-scale biomedical microsystems based on the combination of two additive manufacturing processes: a conventional laser writer to manufacture the overall device structure, and a direct-laser writer based on two-photon polymerization to yield finer details. The process excels for its versatility, accuracy and manufacturing speed and allows for the manufacture of microsystems and implants with overall sizes up to several millimeters and with details down to sub-micrometric structures. As an application example we have focused on manufacturing a biomedical microsystem to analyze the impact of microtextured surfaces on cell motility. This process yielded a relevant increase in precision and manufacturing speed when compared with more conventional rapid prototyping procedures
Rapid fabrication of polymer microfluidic systems for the production of artificial lipid bilayers
A polymer microfluidic device has been fabricated using rapid prototyping techniques. The device was built up to allow the formation and subsequent investigation of artificial bilayer lipid membranes (BLMs). A simple dry film photoresist stamp was used to hot emboss microfluidic channels into PMMA films. Laser micromachining was employed to form an aperture into PMMA films. Laser micromachining was employed to form an aperture through the PMMA channels, across which the BLM was later formed. The dry film phororesist was also used as a simple etch mask for the deep etching of glass substrates in buffered HF solutions, which was used in this work for the production of glass embossing stamps. We show that bilayer films can be successfully produced across laser micromachined apertures in PMMA films
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Quantifying Dimensional Accuracy of a Mask Projection Micro Stereolithography System
Mask Projection Microstereolithography is capable for fabricating true three-dimensional
microparts and hence, holds promise as a potential micro-fabrication process for micro-machine
components. In this paper, the Mask Projection Micro-Stereolithography (MP”SLA) system
developed at the Rapid Prototyping and Manufacturing Institute at Georgia Institute of
Technology is presented. The dimensional accuracy of the system is improved by reducing its
process planning errors. To this effect, the MP”SLA process is mathematically modeled. In this
paper, the irradiance received by the resin surface is modeled as a function of the imaging system
parameters and the pattern displayed on the dynamic mask. The resin used in the system is
characterized to experimentally determine its working curve. This work enables us to compute
the dimensions of a single layer cured using our system. The analytical model is validated by
curing test layers on the system. The model computes layer dimensions within 5% error.Mechanical Engineerin
Computer-Assisted Prototyping of Advanced Microsystems
Contains reports on five research projects.Defense Advanced Research Projects Agency Contract DABT 63-95-C-0088Stanford Universit
Semi-automated creation of converged iTV services: From macromedia director simulations to services ready for broadcast
While sound and video may capture viewersâ attention, interaction can captivate them. This has not been available prior to the advent of Digital Television. In fact, what lies at the heart of the Digital Television revolution
is this new type of interactive content, offered
in the form of interactive Television (iTV) services. On top of that, the new world of converged networks has created a demand for a new type of converged services on a range of mobile terminals (Tablet PCs, PDAs and mobile phones). This paper aims at presenting a new approach to service creation that allows for the semi-automatic translation of simulations and rapid prototypes created in the accessible desktop
multimedia authoring package Macromedia Director
into services ready for broadcast. This is achieved by a series of tools that de-skill and speed-up the process of creating digital TV user interfaces (UI) and applications for mobile terminals.
The benefits of rapid prototyping are essential for the production of these new types of services, and are therefore discussed in the first section of this paper.
In the following sections, an overview of the
operation of content, service, creation and management sub-systems is presented, which illustrates why these tools compose an important and integral part of a system responsible of creating, delivering and managing converged broadcast and telecommunications services.
The next section examines a number of metadata
languages candidates for describing the iTV services user interface and the schema language adopted in this project. A detailed description of the operation of the two tools is provided to offer an insight of how they can be used to de-skill and speed-up the process of creating digital TV user interfaces and applications for mobile terminals. Finally, representative broadcast oriented and telecommunication oriented converged service components are also introduced, demonstrating how these tools have been used to generate different types of services
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