130,832 research outputs found
Recommended from our members
Development of an Automated Multiple Material Stereolithography Machine
An automated Multiple Material Stereolithography (MMSL) machine was developed by
integrating components of a 3D Systems 250/50 stereolithography (SL) machine in a separate
stand-alone system and adapting them to function with additional components required for
MMSL operation. We previously reported retrofitting a 250/50 SL machine with multiple vats
to accommodate multiple material fabrication for building a wide variety of multi-material
models (Wicker et al., 2004). In the MMSL retrofit, spatial constraints limited the multiple vats
located circumferentially on a vertical rotating vat carousel to cross-sectional areas of
approximately 4.5-inches by 4.5-inches. The limited build size of the retrofitted 250/50
motivated the full development of a new system with multiple material build capabilities
comparable to the build envelope of the original 250/50 machine. The new MMSL machine
required fabrication of a large system frame, incorporating various 250/50 components and
software, and adding a variety of new components and software. By using many existing
components and software, the previous engineering development of 3D Systems could be
directly applied to this new technology. Components that were transferred from an existing
250/50 to the MMSL machine included the complete optical system (including the optics plate
with laser, mirrors, beam expander, scanning mirrors, and focusing lens), the rim assembly
(including the laser beam profilers), the associated controllers (computer system, scanning mirror
controller, power supply-vat controller) and the wiring harness. In addition to the new frame, the
MMSL machine required the development of a new rotating vat carousel system, platform
assembly, multi-pump filling/leveling system, and a custom LabVIEW® control system to
provide automated control over the MMSL process. The overall operation of the MMSL system
was managed using the LabVIEW® program, which also included controlling a new vat leveling
system and new linear and rotational stages, while the 3D Systems software (Buildstation 4.0)
was retained for controlling the laser scanning process. As a demonstration of MMSL
technology, simple multi material parts were fabricated with vertically and horizontally oriented
interfaces. The fully functional MMSL system offers enormous potential for fabricating a wide
variety of multiple material functional devices.Mechanical Engineerin
Recommended from our members
Integrating information and knowledge for enterprise innovation
It has widely been accepted that enterprise integration, can be a source of socio-technical and cultural problems within organisations wishing to provide a focussed end-to-end business service. This can cause possible “straitjacketing” of business process architectures, thus suppressing responsive business re-engineering and competitive advantage for some companies. Accordingly, the current typology and emergent forms of Enterprise Resource Planning (ERP) and Enterprise Application Integration (EAI) technologies are set in the context of understanding information and knowledge integration philosophies. As such, key influences and trends in emerging IS integration choices, for end-to-end, cost-effective and flexible knowledge integration, are examined. As touch points across and outside organisations proliferate, via work-flow and relationship management-driven value innovation, aspects of knowledge refinement and knowledge integration pose challenges to maximising the potential of innovation and sustainable success, within enterprises. This is in terms of the increasing propensity for data fragmentation and the lack of effective information management, in the light of information overload. Furthermore, the nature of IS mediation which is inherent within decision making and workflow-based business processes, provides the basis for evaluation of the effects of information and knowledge integration. Hence, the authors propose a conceptual, holistic evaluation framework which encompasses these ideas. It is thus argued that such trends, and their implications regarding enterprise IS integration to engender sustainable competitive advantage, require fundamental re-thinking
Recommended from our members
Hybrid Manufacturing: Integrating Direct Write and Stereolithography
A commercial stereolithography (SL) machine was modified to integrate fluid dispensing or
direct-write (DW) technology with SL in an integrated manufacturing environment for
automated and efficient hybrid manufacturing of complex electrical devices, combining threedimensional (3D) electrical circuitry with SL-manufactured parts. The modified SL system
operates similarly to a commercially available machine, although build interrupts were used to
stop and start the SL build while depositing fluid using the DW system. An additional linear
encoder was attached to the SL platform z-stage and used to maintain accurate part registration
during the SL and DW build processes. Individual STL files were required as part of the
manufacturing process plan. The DW system employed a three-axis translation mechanism that
was integrated with the commercial SL machine. Registration between the SL part, SL laser and
the DW nozzle was maintained through the use of 0.025-inch diameter cylindrical reference
holes manufactured in the part during SL. After depositing conductive ink using DW, the SL
laser was commanded to trace the profile until the ink was cured. The current system allows for
easy exchange between SL and DW in order to manufacture fully functional 3D electrical
circuits and structures in a semi-automated environment. To demonstrate the manufacturing
capabilities, the hybrid SL/DW setup was used to make a simple multi-layer SL part with
embedded circuitry. This hybrid system is not intended to function as a commercial system, it is
intended for experimental demonstration only. This hybrid SL/DW system has the potential for
manufacturing fully functional electromechanical devices that are more compact, less expensive,
and more reliable than their conventional predecessors, and work is ongoing in order to fully
automate the current system.Mechanical Engineerin
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
A survey on cyber security for smart grid communications
A smart grid is a new form of electricity network with high fidelity power-flow control, self-healing, and energy reliability and energy security using digital communications and control technology. To upgrade an existing power grid into a smart grid, it requires significant dependence on intelligent and secure communication infrastructures. It requires security frameworks for distributed communications, pervasive computing and sensing technologies in smart grid. However, as many of the communication technologies currently recommended to use by a smart grid is vulnerable in cyber security, it could lead to unreliable system operations, causing unnecessary expenditure, even consequential disaster to both utilities and consumers. In this paper, we summarize the cyber security requirements and the possible vulnerabilities in smart grid communications and survey the current solutions on cyber security for smart grid communications. © 2012 IEEE
- …