1,698 research outputs found
Recommended from our members
Expanding Rapid Prototyping for Electronic Systems Integration of Arbitrary Form
An innovative method for rapid prototyping (RP) of electronic circuits with components
characteristic of typical electronics applications was demonstrated using an enhanced version of
a previously developed hybrid stereolithography (SL) and direct write (DW) system, where an
existing SL machine was integrated with a three-axis DW fluid dispensing system for combined
arbitrary form electronic systems manufacturing. This paper presents initial efforts at embedding
functional electronic circuits using the hybrid SL/DW system. A simple temperature-sensitive
circuit was selected, which oscillated an LED at a frequency proportional to the temperature
sensed by the thermistor. The circuit was designed to incorporate all the required electronic
components within a 2.5” x 2” x 0.5” SL part. Electrical interconnects between electronic
components were deposited on the SL part with a DW system using silver conductive ink lines.
Several inks were deposited, cured, and tested on a variety of SL resin substrates, and the E 1660
ink (Ercon Inc, Wareham, MA) was selected due to its measured lowest average resistivity on
the SL substrates. The finished circuit was compared with Printed Circuit Board (PCB)
technology for functionality. The electronic components used here include a low voltage battery,
LM 555 timer chip, resistors, a thermistor, capacitors, and Light Emitting Diodes (LEDs). This
circuit was selected because it (1) represented a simple circuit combining many typically used
electronic components and thus provided a useful demonstration for integrated electronic
systems manufacturing applicable to a wide variety of devices, and (2) provided an indication of
the parasitic resistances and capacitances introduced by the fabrication process due to its
sensitivity to manufacturing variation. The hybrid technology can help achieve significant size
reductions, enable systems integration in atypical forms, a natural resistance to reverse
engineering and possibly increase maximum operating temperatures of electronic circuits as
compared to the traditional PCB process. This research demonstrates the ability of the hybrid
SL/DW technology for fabricating combined electronic systems for unique electronics
applications in which arbitrary form is a requirement and traditional PCB technology cannot be
used.Mechanical Engineerin
Process planning for thick-film mask projection micro stereolithography
Mask Projection micro Stereolithography (MPuSLA) is an additive manufacturing process used to build physical components out of a photopolymer resin. Existing MPuSLA technology cut the CAD model of part into slices by horizontal planes and the slices are stored as bitmaps. A layer corresponding to the shape of each bitmap gets cured. This layer is coated with a fresh layer of resin by lowering the Z-stage inside a vat holding the resin and the next layer is cured on top of it.
In our Thick-film MPuSLA(TfMPuSLA) system, incident radiation, patterned by a dynamic mask, passes through a fixed transparent substrate to cure photopolymer resin. The existing MPuSLA fabrication models can work only for controlling the lateral dimension, without any control over the thickness of the cured part. The proposed process plan controls both the lateral dimensions and the thickness of profile of the cured part.
In this thesis, a novel process planning for TfMPuSLA method is developed, to fabricate films on fixed flat substrate. The process of curing a part using this system is analytically modeled as the column cure model. It is different from the conventional process - layer cure model. Column means that a CAD model of part is discretized into vertical columns instead of being sliced into horizontal layers, and all columns get cured simultaneously till the desired heights. The process planning system is modularized into geometrical, chemical, optical, mathematical and physical modules and validated by curing test parts on our system. The thesis formulates a feasible process planning method, providing a strong basis for continued investigation of MPuSLA technology in microfabrication, such as micro lens fabrication.M.S.Committee Chair: Rosen, David W.; Committee Member: Das, Suman; Committee Member: Grover, Martha A
From 3D Models to 3D Prints: an Overview of the Processing Pipeline
Due to the wide diffusion of 3D printing technologies, geometric algorithms
for Additive Manufacturing are being invented at an impressive speed. Each
single step, in particular along the Process Planning pipeline, can now count
on dozens of methods that prepare the 3D model for fabrication, while analysing
and optimizing geometry and machine instructions for various objectives. This
report provides a classification of this huge state of the art, and elicits the
relation between each single algorithm and a list of desirable objectives
during Process Planning. The objectives themselves are listed and discussed,
along with possible needs for tradeoffs. Additive Manufacturing technologies
are broadly categorized to explicitly relate classes of devices and supported
features. Finally, this report offers an analysis of the state of the art while
discussing open and challenging problems from both an academic and an
industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and
Innovation action; Grant agreement N. 68044
Recommended from our members
A Novel Projection Based Electro-Stereolithography (PES) Process for Composite Printing
Most current additive manufacturing processes can only process one material in one build.
Few of them are able to fabricate multiple materials and composites, with limited choices of
materials. In this research, we propose a novel Projection based Electro-Stereolithography (PES)
process, which is able to fabricate composites with high resolution and fast speed, and a big
range of material choices. The proposed novel additive manufacturing process integrates
projection-based stereolithography and electrophotography approaches by using a
photoconductive film and digital micro-mirror device (DMD). In PES, a photoconductive film is
used to collect charged particles in the regions illuminated by light. More specifically, a laser
beam is scanning on the film to create a latent image on the film and then a layer of charged
particles is attracted to the illuminated area. A liquid bridge system and a stamping system have
been developed to transfer particles from the film to liquid resin precisely. Furthermore, a digital
mask is used to pattern the light irradiation of the DMD chip to selectively cure the
photopolymer liquid resin and particles of that layer. By transferring particles with designed
patterns to the resin in a projection based stereolithography system, we will be able to fabricate
composites with various materials at microscopic resolutions very quickly. Challenges in this
novel manufacturing process, including transferring of particles and curing control, have been
discussed and addressed. The corresponding key parameters of the particles collecting, dropping
and curing in the PES system have been identified. A proof-of-concept PES testbed has been
developed and a couple of tests have been performed to validate the feasibility of the proposed
additive manufacturing approach.Mechanical Engineerin
Recommended from our members
Dynamic Resolution Control in a Laser Projection Based Stereolithography System
In a typical Additive Manufacturing system, it is critical to make a trade-off between the
resolution and build area for applications in which varied dimensional sizes, feature sizes, and
accuracies are desired. The lack of the capability in adjusting resolution dynamically during
building processes limits the use of AM in fabricating complex structures with big layer areas
and small features. In this paper, a novel AM system with dynamic resolution control by
integrating a laser projection in vat photopolymerization process is presented. Theoretical models
and parameter characterizations are presented for the developed AM system. Accordingly, the
process planning and mask image planning approaches for fabricating models with varied
dimensional sizes and feature sizes have been developed. Multiple test cases based on various
types of structures have been performed.Mechanical Engineerin
An experimental investigation into the dimensional error of powder-binder three-dimensional printing
This paper is an experimental investigation into the dimensional error of the rapid prototyping additive process of powder-binder three-dimensional printing. Ten replicates of a purpose-designed part were produced using a three-dimensional printer, and measurements of the internal and external features of all surfaces were made using a general purpose coordinate measuring machine. The results reveal that the bases of all replicates (nominally flat) have a concave curvature, producing a flatness error of the primary datum. This is in contrast to findings regarding other three-dimensional printing processes, widely reported in the literature, where a convex curvature was observed. All external surfaces investigated in this study showed positive deviation from nominal values, especially in the z-axis. The z-axis error consisted of a consistent positive cumulative error and a different constant error in different replicates. By compensating for datum surface error, the average total height error of the test parts can be reduced by 25.52 %. All the dimensional errors are hypothesised to be explained by expansion and the subsequent distortion caused by layer interaction during and after the printing process
The potential of additive manufacturing in the smart factory industrial 4.0: A review
Additive manufacturing (AM) or three-dimensional (3D) printing has introduced a novel production method in design, manufacturing, and distribution to end-users. This technology has provided great freedom in design for creating complex components, highly customizable products, and efficient waste minimization. The last industrial revolution, namely industry 4.0, employs the integration of smart manufacturing systems and developed information technologies. Accordingly, AM plays a principal role in industry 4.0 thanks to numerous benefits, such as time and material saving, rapid prototyping, high efficiency, and decentralized production methods. This review paper is to organize a comprehensive study on AM technology and present the latest achievements and industrial applications. Besides that, this paper investigates the sustainability dimensions of the AM process and the added values in economic, social, and environment sections. Finally, the paper concludes by pointing out the future trend of AM in technology, applications, and materials aspects that have the potential to come up with new ideas for the future of AM explorations
Recommended from our members
Fabrication of Smooth Surfaces Based on Mask Projection Stereolithography
The surface finish is critical for applications such as micro-fluid mixing and self-assembly that
requires smooth fluidic flow and mechanical rotation respectively. However, in layer-based additive
manufacturing processes, it is well known that the stair-stepping effect exists in the fabricated surfaces
since a three-dimensional model is approximated by a set of two-dimensional layers. The fabricated
surfaces are especially poor for the ones that are close to the horizontal plane. In this paper a novel
approach for achieving improved surface finish has been presented for the mask-image-projection-based
Stereolithography (MIP-SL) process. Theoretical models and parameter characterization are presented
with experimental verification. The developed approaches have been incorporated in the process planning
of the MIP-SL process. Multiple test cases based on various types of curved surfaces have been
performed. A comparison of the built results based on the traditional and the newly developed
approaches has been discussed to illustrate the effectiveness of our method.Mechanical Engineerin
- …