5,361 research outputs found
Modelling and simulation of paradigms for printed circuit board assembly to support the UK's competency in high reliability electronics
The fundamental requirement of the research reported within this thesis is the provision
of physical models to enable model based simulation of mainstream printed circuit
assembly (PCA) process discrete events for use within to-be-developed (or under
development) software tools which codify cause & effects knowledge for use in product
and process design optimisation. To support a national competitive advantage in high
reliability electronics UK based producers of aircraft electronic subsystems require
advanced simulation tools which offer model based guidance. In turn, maximization of
manufacturability and minimization of uncontrolled rework must therefore enhance inservice
sustainability for ‘power-by-the-hour’ commercial aircraft operation business
models. [Continues.
Reliability handbook for silicon monolithic microcircuits. Volume 2 - Failure mechanisms of monolithic microcircuits
Reliability handbook for silicon monolithic microcircuits - failure mechanism
The design and implementation of a flexible manufacturing system for a surface mounting production line
A project report submitted to the Faculty of Engineering,
University of the Witwatersrand, Johannesburg, in partial
fulfillment of the requirements for the degree of Master of
Science in Engineering.The viability of introducing a Surface Mount
production line is chiefly determined by the
reliability characteristics of the components being
used. Surface Mount Technology (SMT) is entirely new
and although related to traditional through-hole
processes, requires different components, assembly
techniques and design methods. The purpose of the
literature survey is primarily to determine whether
surface mount components meet today's industrial
requirements with respect to their manufacturing
reliability and availability. A brief review of the
evolution of SMT is also presented. This study finds
that the implementation of SMT should be given highest
priority by manufacturing companies in order to
maintain their share of the marketplace.
Surface Mount Technology embodies a totally new
automated circuit assembly process, using a new
generation of electronic comporents: surface mounted
devices (SMDs). Smaller than conventional components,
SMDs are placed onto the surface of the substrate.
From this, the fundamental difference between SMD
assembly and convencional through-hole component
assembly arises; SMD component positioning is
relative, not absolute.
When a through-hole component is inserted into a pcb,
either the leads go through the hales or they don't.
An SMD, however, is placed onto the substrate surface,
it's position only relative to the solder lands, and
placement accuracy is therefore influenced by
variations in the substrate track pattern, component
size, and placement machine accuracy.
Other factors influence the layout of SMD substrates.
For example, will the board be a mixed-print ( a
combination of through-hole components and SMDs) or an
all-SMD design? Will SMDs be placed on one side of the
substrate or both? And there are process
considerations like what type of machine will place
the components and how will they be soldered?
This project describes in detail the processes
involved in setting up an SMT facility. A simulation
program was developed to verify the viability of these
processes. The simulation program was also applied to
an existing SMT facility and together with developed
optimization software, attempted to identify and
resolve some of the major problems. All this was
achieved, and the extent to which simulation could be
used as an efficient production tool, was highlighted.AC201
Pathway to the PiezoElectronic Transduction Logic Device
The information age challenges computer technology to process an
exponentially increasing computational load on a limited energy budget - a
requirement that demands an exponential reduction in energy per operation. In
digital logic circuits, the switching energy of present FET devices is
intimately connected with the switching voltage, and can no longer be lowered
sufficiently, limiting the ability of current technology to address the
challenge. Quantum computing offers a leap forward in capability, but a clear
advantage requires algorithms presently developed for only a small set of
applications. Therefore, a new, general purpose, classical technology based on
a different paradigm is needed to meet the ever increasing demand for data
processing.Comment: in Nano Letters (2015
Inspection System And Method For Bond Detection And Validation Of Surface Mount Devices Using Sensor Fusion And Active Perception
A hybrid surface mount component inspection system which includes both vision and infrared inspection techniques to determine the presence of surface mount components on a printed wiring board, and the quality of solder joints of surface mount components on printed wiring boards by using data level sensor fusion to combine data from two infrared sensors to obtain emissivity independent thermal signatures of solder joints, and using feature level sensor fusion with active perception to assemble and process inspection information from any number of sensors to determine characteristic feature sets of different defect classes to classify solder defects.Georgia Tech Research Corporatio
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