1,837 research outputs found
Allocation of component types to machines in the automated assembly of printed circuit boards
Duman, Ekrem (Dogus Author) -- An earlier version of this paper which has been presented at ISCIS'06: The 21st International Symposium on Computer and Information Sciences, November 1-3, 2006 Istanbul, Turkey, has been published in Lecture Notes in Computer Science [18].Although the use of electronic component placement machines has brought reliability and speed to the printed circuit board (PCB) assembly process, to get higher utilization, one needs to solve the resulting complex operations research problems efficiently. In this study, the problem of distributing the assembly workload to two machines deployed on an assembly line with two identical component placement machines to minimize the line idle time is considered. This problem is NP-Complete even in its simplest form. A mathematical model and several heuristics have been proposed to solve this problem efficiently
Algorithmic Solutions for Combinatorial Problems in Resource Management of Manufacturing Environments
This thesis studies the use of heuristic algorithms in a number of combinatorial problems that occur in various resource constrained environments. Such problems occur, for example, in manufacturing, where a restricted number of resources (tools, machines, feeder slots) are needed to perform some operations. Many of these problems turn out to be computationally intractable, and heuristic algorithms are used to provide efficient, yet sub-optimal solutions. The main goal of the present study is to build upon existing methods to create new heuristics that provide improved solutions for some of these problems. All of these problems occur in practice, and one of the motivations of our study was the request for improvements from industrial sources. We approach three different resource constrained problems. The first is the tool switching and loading problem, and occurs especially in the assembly of printed circuit boards. This problem has to be solved when an efficient, yet small primary storage is used to access resources (tools) from a less efficient (but unlimited) secondary storage area. We study various forms of the problem and provide improved heuristics for its solution. Second, the nozzle assignment problem is concerned with selecting a suitable set of vacuum nozzles for the arms of a robotic assembly machine. It turns out that this is a specialized formulation of the MINMAX resource allocation formulation of the apportionment problem and it can be solved efficiently and optimally. We construct an exact algorithm specialized for the nozzle selection and provide a proof of its optimality. Third, the problem of feeder assignment and component tape construction occurs when electronic components are inserted and certain component types cause tape movement delays that can significantly impact the efficiency of printed circuit board assembly. Here, careful selection of component slots in the feeder improves the tape movement speed. We provide a formal proof that this problem is of the same complexity as the turnpike problem (a well studied geometric optimization problem), and provide a heuristic algorithm for this problem.Siirretty Doriast
Optimization of product assignment to assembly lines
Dissertação de mestrado em Industrial engineering and ManagementThe work presented in this dissertation was developed in an industrial context integrated in the production control and management department of the Bosch Car Multimedia Portugal S.A – Braga automatic insertion.
The problem addressed in this dissertation was finding the best distribution of product families to assign in different lines according to the physical and technical constraints of the assembly lines.
In the approach of the problem, it was used tools and techniques of the Operational Research discipline through mathematical modeling, in order to analyze complex situation and obtain more efficient solutions to help in the decision-making process. Based on production data, production needs forecasts and assembly line physical availability, models with different sets of constraints and objective functions were created to present solutions that best fit the question and the specific problem of the present production context.
Through specific software that suited the problem, the previously created models were solved, and the solutions were analyzed and evaluated to suit the company’s current needs and for possible and feasible implementation of the solutions.O trabalho apresentado nesta dissertação foi desenvolvido em contexto industrial integrado no departamento de planeamento e controlo de produção da área de inserção automática da Bosch Car Multimédia Portugal S.A - Braga.
O problema abordado nesta dissertação foi encontrar a melhor distribuição de famílias de produtos a alocar nas diferentes linhas de produção de acordo com as suas restrições físicas e técnicas.
Na abordagem do problema recorreu-se a técnicas de Investigação Operacional através de modelação matemática, para analisar situações complexas e obter soluções mais eficientes. Tendo como base dados da produção, previsões de necessidades e disponibilidade física da produção, foram criados modelos com diferentes conjuntos de restrições e funções objetivo por forma a apresentar soluções que melhor se adequassem à pergunta e ao problema específico do contexto produtivo presente.
Através da utilização de software, foram resolvidos os modelos criados anteriormente, sendo que as soluções foram analisadas e avaliadas para a adequação às necessidades atuais da empresa e para a sua possível e viável implementação
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.
A reference architecture for flexibly integrating machine vision within manufacturing
A reference architecture provides an overall framework that may embrace models, methodologies and
mechanisms which can support the lifecycle of their target domain. The work described in this thesis
makes a contribution to establishing such a generally applicable reference architecture for supporting
the lifecycIe of a new generation of integrated machine vision systems.
Contemporary machine vision systems consist of a complex combination of mechanical engineering,
the hardware and software of an electronic processor, plus optical, sensory and lighting components.
"This thesis is concerned with the structure of the software which characterises the system application.
The machine vision systems which are currently used within manufacturing industry are difficult to
integrate within the information systems required within modem manufacturing enterprises. They are
inflexible in all but the execution of a range of similar operations, and their design and implementation
is often such that they are difficult to update in the face of the required change inherent within modem
manufacturing.
The proposed reference architecture provides an overall framework within which a number of supporting
models, design methodologies, and implementation mechanisms can combine to provide support
for the rapid creation and maintenance of highly structured machine vision applications. These applications
comprise modules which can be considered as building blocks of CIM systems. Their integrated
interoperation can be enabled by the emerging infrastructural tools which will be required to underpin
the next generation of flexibly integrated manufacturing systems.
The work described in this thesis concludes that the issues of machine vision applications and the
issues of integration of these applications within manufacturing systems are entirely separate. This separation
is reflected in the structure of the thesis. PART B details vision application issues while PAIIT C
deals with integration. The criteria for next generation integrated machine vision systems, derived in
PART A of the thesis, are extensive. In order to address these criteria and propose a complete architecture,
a "thin slice" is taken through the areas of vision application, and integration at the lifecycle
stages of design, implementation, runtime and maintenance.
The thesis describes the reference architecture, demonstrates its use though a proof of concept implementation
and evaluates the support offered by the architecture for easing the problems of software change
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Integrated methodology for board assignment and component allocation in printed circuit board assembly
The purpose of this research is to develop an approach to minimize
makespan for assigning boards to production lines. Because of sequence-dependent
setup issue, board assignment and component allocation have to be performed
concurrently. An integrated methodology is proposed to obtain a solution of the
two problems. The methodology consists of seven phases: PCB grouping, family
decomposition, subfamily sequencing, Keep Tool Needed Soonest (KTNS),
component setup determination, component allocation, and board assignment.
PCB grouping based on component similarity between boards is used to
reduce the problem size. Family decomposition is used when total number of feeder
slots required by a family exceeds feeder capacity. Subfamily sequencing and Keep
Tool Needed Soonest are applied to minimize the number of component setups.
Classification of setup components into standard, semi-standard, and custom setup
components is performed to reduce the complexity of the component allocation
problem. A component allocation algorithm is developed to balance workload
across machines. Assigning board families to production lines is performed using a
modification of Longest Processing Time (LPT) rule. Assigning entire PCB
families to production lines to minimize makespan is difficult to accomplish since
the amount of production time for each family is very large compared to that of
individual PCB lot. Splitting some subfamilies is allowed as long as this does not
increase makespan. The PCB grouping, family decomposition, subfamily
sequencing, Keep Tool Needed Soonest (KTNS), and component setup
determination procedures are derived from published research results. The
component allocation and board assignment are developed in this research, as well
as an overall methodology to integrate the entire problem.
Data provided by published literature are employed to evaluate performance
of the component allocation algorithm and the integrated methodology. To examine
the applicability of the methodology, an industrial data is used with the total
imbalance due to setup time and placement time of individual PCB and global
makespan as the performance measures. Experimentation is conducted with
simulated data based on an industry data to investigate impact of threshold value,
feeder capacity, and characteristics of data sets on system performance
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