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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Process planning for thick-film mask projection micro stereolithography

Zhao, Xiayun 26 March 2009 (has links)
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.
32

Desenvolvimento de um sistema semi-generativo para planejamento de processo auxiliado por computador para ambiente de usinagem / Development of a hybrid computer aided process planning System for a machining enviroment

Farias, João Batista Sá de January 2008 (has links)
Este trabalho apresenta o desenvolvimento de um sistema para automatizar o planejamento de processo na fabricação de peças por usinagem, adotando uma metodologia semi-generativa, ou híbrida, que se utiliza de informações de arquivos gráficos padrão STEP. O sistema interpreta o arquivo STEP (protocolo de aplicação AP203) de um sistema CAD qualquer e identifica as geometrias existentes no arquivo. Um algoritmo desenvolvido inicialmente para geometrias cilíndricas, possível de ser implementado para outras geometrias, como furos e rasgos de chavetas. Com as informações provenientes do algoritmo de interpretação do STEP, o sistema interage com um banco de dados para planejar as etapas de usinagem do produto. O banco de dados contém informações relativas a máquinas, ferramentas, operações e materiais. Rotinas associadas ao banco de dados permitem a definição e seleção de parâmetros de usinagem e máquina otimizadas a cada etapa do processo, adequadas ao projeto do componente. O sistema é considerado semi-generativo, na medida em que permite ao processista acrescentar novas etapas de processo caso o produto tenha outras features manufaturáveis, que não tenham sido obtidas de forma automática. O resultado do sistema permite a geração do plano de processo otimizado para determinado componente em função das informações disponibilizadas no banco de dados de manufatura. / This work presents the development of a system for process planning automation manufacturing parts by machining. A hybrid methodology was adopted using information from standard STEP graphical files. The system interprets the design of geometries file STEP (ISO application protocol AP203) in a system CAD with an algorithm developed initially for cylindrical geometries, being possible to be implemented for other geometries, as holes and slots. As the information proceeding from the interpretation algorithm of the STEP, the system interacts with the planning the stages of product machining. The data base contains relative information from the machines, tools, operations and materials. Routines associated with the data base allow the definition and election of parameters to optimized process machining and machine to each stage of the process, adjusted to the component project. The process planning system is based in three modules: the algorithm for interpretation STEP files, the data base with the manufacture information and the system graphical interface. The system is considered hybrid, in a sense that allows the user to add new stages to the process in the case that the product has others features manufactured that have not been recognized of automatic form. The result of the system allows the generation of an optimized process plan for determined component in relation to the information available in the manufacture data base.
33

Desenvolvimento de um sistema semi-generativo para planejamento de processo auxiliado por computador para ambiente de usinagem / Development of a hybrid computer aided process planning System for a machining enviroment

Farias, João Batista Sá de January 2008 (has links)
Este trabalho apresenta o desenvolvimento de um sistema para automatizar o planejamento de processo na fabricação de peças por usinagem, adotando uma metodologia semi-generativa, ou híbrida, que se utiliza de informações de arquivos gráficos padrão STEP. O sistema interpreta o arquivo STEP (protocolo de aplicação AP203) de um sistema CAD qualquer e identifica as geometrias existentes no arquivo. Um algoritmo desenvolvido inicialmente para geometrias cilíndricas, possível de ser implementado para outras geometrias, como furos e rasgos de chavetas. Com as informações provenientes do algoritmo de interpretação do STEP, o sistema interage com um banco de dados para planejar as etapas de usinagem do produto. O banco de dados contém informações relativas a máquinas, ferramentas, operações e materiais. Rotinas associadas ao banco de dados permitem a definição e seleção de parâmetros de usinagem e máquina otimizadas a cada etapa do processo, adequadas ao projeto do componente. O sistema é considerado semi-generativo, na medida em que permite ao processista acrescentar novas etapas de processo caso o produto tenha outras features manufaturáveis, que não tenham sido obtidas de forma automática. O resultado do sistema permite a geração do plano de processo otimizado para determinado componente em função das informações disponibilizadas no banco de dados de manufatura. / This work presents the development of a system for process planning automation manufacturing parts by machining. A hybrid methodology was adopted using information from standard STEP graphical files. The system interprets the design of geometries file STEP (ISO application protocol AP203) in a system CAD with an algorithm developed initially for cylindrical geometries, being possible to be implemented for other geometries, as holes and slots. As the information proceeding from the interpretation algorithm of the STEP, the system interacts with the planning the stages of product machining. The data base contains relative information from the machines, tools, operations and materials. Routines associated with the data base allow the definition and election of parameters to optimized process machining and machine to each stage of the process, adjusted to the component project. The process planning system is based in three modules: the algorithm for interpretation STEP files, the data base with the manufacture information and the system graphical interface. The system is considered hybrid, in a sense that allows the user to add new stages to the process in the case that the product has others features manufactured that have not been recognized of automatic form. The result of the system allows the generation of an optimized process plan for determined component in relation to the information available in the manufacture data base.
34

Uma avaliação da aplicação de sistemas de planejamento de processos (CAPP) na indústria de manufatura brasileira / An applicability evaluation of computer aided process planning systems (CAPP) in the Brazilian manufacturing industry

Leonardo Charles Malafaia Paranaguá 05 October 2001 (has links)
A importância deste trabalho encontra suas fundamentações na atual relevância de pesquisas sobre avaliação de impacto de sistemas de informação e na importância dos sistemas CAPP para a indústria de manufatura. A necessidade de avaliar sistemas de informação surgiu de um fenômeno conhecido como paradoxo da produtividade (falta de evidência de retornos para altíssimos investimentos). Já o CAPP é um sistema fundamental na interface de Engenharias e Produções, sendo gerador de informações para toda a empresa. Para a obtenção este objetivo foram realizadas análises de dados colhidos em 11 casos investigados. / The importance of this work meets its foundation both in the nowadays relevance of studies on information systems impact and in the importance of CAPP systems to the manufacturing industry. The necessity of evaluating information systems emerged from a situation known as the productivity paradox (lack of return evidence in despite high investments). Regarding the CAPP, it is a fundamental system to do the interface between the Project and the Production areas, being also a generator of important information to the whole company. To reach these goals, some analysis were carried on data collected from 11 case studies.
35

Desenvolvimento de um sistema semi-generativo para planejamento de processo auxiliado por computador para ambiente de usinagem / Development of a hybrid computer aided process planning System for a machining enviroment

Farias, João Batista Sá de January 2008 (has links)
Este trabalho apresenta o desenvolvimento de um sistema para automatizar o planejamento de processo na fabricação de peças por usinagem, adotando uma metodologia semi-generativa, ou híbrida, que se utiliza de informações de arquivos gráficos padrão STEP. O sistema interpreta o arquivo STEP (protocolo de aplicação AP203) de um sistema CAD qualquer e identifica as geometrias existentes no arquivo. Um algoritmo desenvolvido inicialmente para geometrias cilíndricas, possível de ser implementado para outras geometrias, como furos e rasgos de chavetas. Com as informações provenientes do algoritmo de interpretação do STEP, o sistema interage com um banco de dados para planejar as etapas de usinagem do produto. O banco de dados contém informações relativas a máquinas, ferramentas, operações e materiais. Rotinas associadas ao banco de dados permitem a definição e seleção de parâmetros de usinagem e máquina otimizadas a cada etapa do processo, adequadas ao projeto do componente. O sistema é considerado semi-generativo, na medida em que permite ao processista acrescentar novas etapas de processo caso o produto tenha outras features manufaturáveis, que não tenham sido obtidas de forma automática. O resultado do sistema permite a geração do plano de processo otimizado para determinado componente em função das informações disponibilizadas no banco de dados de manufatura. / This work presents the development of a system for process planning automation manufacturing parts by machining. A hybrid methodology was adopted using information from standard STEP graphical files. The system interprets the design of geometries file STEP (ISO application protocol AP203) in a system CAD with an algorithm developed initially for cylindrical geometries, being possible to be implemented for other geometries, as holes and slots. As the information proceeding from the interpretation algorithm of the STEP, the system interacts with the planning the stages of product machining. The data base contains relative information from the machines, tools, operations and materials. Routines associated with the data base allow the definition and election of parameters to optimized process machining and machine to each stage of the process, adjusted to the component project. The process planning system is based in three modules: the algorithm for interpretation STEP files, the data base with the manufacture information and the system graphical interface. The system is considered hybrid, in a sense that allows the user to add new stages to the process in the case that the product has others features manufactured that have not been recognized of automatic form. The result of the system allows the generation of an optimized process plan for determined component in relation to the information available in the manufacture data base.
36

Modellierungsmethoden für die Prozessplanung

Szélig , Nikoletta, Vajna , Sandor, Schabacker, Michael 28 September 2017 (has links) (PDF)
Einführung Die aktuelle Situation in der Produktentwicklung ist durch zunehmend dynamische und komplexe Aufgabenstellungen gekennzeichnet. Die Entwicklung eines Produktes ist kein linearer Prozess, der kontinuierlich über klar definierte Schritte zum Ziel geführt wird. Nur wenige Produkte werden neu konstruiert, meist handelt es sich dabei aber um Anpassungs-, Änderungs- oder Variantenkonstruktionen (Vajna 1982, Pahl & Beitz 1986). Ein weiterer Aspekt bei der Entwicklung ist, dass die dort verwendeten Prozesse schnell und ohne großen Aufwand in Prozessmanagementwerkzeuge eingebunden werden müssen. Diese Werkzeuge wiederum verwenden verschiedene Modellierungsansätze, wie z.B. die Netzplantechnik, die Design Structure Matrix (DSM) und die Containermodellierung. Gegenstand dieses Beitrages ist es, diese verschiedenen Ansätze zu analysieren und ihre Vor- bzw. Nachteile aufzuzeigen. Dabei hat sich herausgestellt, dass es vorteilhaft ist, eine Kombination der zuvor genannten Methoden zu verwenden. Des Weiteren werden auch die Schnittstellen von BPMN, DSM und Containermodellierung näher beleuchtet.
37

Prerequisites for Automatically Creating Work Instructions in Augmented Reality for Assembly of Gripen E : a case study at Saab Aeronautics

Kamran, Skander, Mäkelä, Alexander January 2020 (has links)
This thesis work has been carried out at the company Saab AB Aeronautics, which manufactures the military aircraft Gripen E. Today, the company uses 3D work instructions for assembly of Gripen E, which is displayed on a computer screen for the shop floor workers. The company has an interest in investigating whether today's work instructions can be visualized in an Augmented Reality interface by reusing available data. This work has been limited to studying wire harness assembly, which is a main part of the final assembly. The methodology case study in combination with the method Requirements Engineering has been used to analyze the company's possibilities. Data collection has been conducted with internal interviews, studying internal materials and internal courses. The result chapter contains two parts, where the first part presents a situation analysis of how today's work instructions are created in the software DELMIA and what data that is needed. The second part presents a requirements specification for an Augmented Reality Work Instruction for assembly of Gripen E. In the discussion, the situation analysis is compared with the requirements to answer which data that could be reused for creating Augmented Reality Work Instructions and what challenges that may arise. This study shows that the company has prerequisites for creating work instructions in Augmented Reality, as there is available data containing 3D models structured according to an assembly sequence with associated descriptive information.
38

Modellierungsmethoden für die Prozessplanung

Szélig, Nikoletta, Vajna, Sandor, Schabacker, Michael January 2012 (has links)
Einführung Die aktuelle Situation in der Produktentwicklung ist durch zunehmend dynamische und komplexe Aufgabenstellungen gekennzeichnet. Die Entwicklung eines Produktes ist kein linearer Prozess, der kontinuierlich über klar definierte Schritte zum Ziel geführt wird. Nur wenige Produkte werden neu konstruiert, meist handelt es sich dabei aber um Anpassungs-, Änderungs- oder Variantenkonstruktionen (Vajna 1982, Pahl & Beitz 1986). Ein weiterer Aspekt bei der Entwicklung ist, dass die dort verwendeten Prozesse schnell und ohne großen Aufwand in Prozessmanagementwerkzeuge eingebunden werden müssen. Diese Werkzeuge wiederum verwenden verschiedene Modellierungsansätze, wie z.B. die Netzplantechnik, die Design Structure Matrix (DSM) und die Containermodellierung. Gegenstand dieses Beitrages ist es, diese verschiedenen Ansätze zu analysieren und ihre Vor- bzw. Nachteile aufzuzeigen. Dabei hat sich herausgestellt, dass es vorteilhaft ist, eine Kombination der zuvor genannten Methoden zu verwenden. Des Weiteren werden auch die Schnittstellen von BPMN, DSM und Containermodellierung näher beleuchtet.
39

Framtagning av Arbetsprocess för Generering av Globala Elementblad med stöd av Digitala Underlag : – Ett koncept med dagens programvaruportfölj för Scanias chassimontering / Implementation of Project Portfolio Management : - A case study at Atlas Copco tools

Granberg, Markus January 2012 (has links)
Scania verkar på en global marknad med tillverkning på flera orter och en förutsättning för att kunna garantera kvalité på de produkter som levereras, oavsett vart de produceras, är ett konsekvent tillämpat standardiserat arbetssätt vid tillverkning och montering. Monteringsbeskrivningar - eller elementblad som de benämns på Scania är en viktig del i att kommunicera detta "standardiserade arbetssätt" över hela företaget och alla desstillverkningsenheter. Det s.k. standardiserade arbetssättet är relativt väl utvecklat mellan de verkstäder som monterar samma typ av huvudkomponenter, men i ett vidare perspektiv så förekommer det mellan olika enheter såväl skillnader i presentation av data i elementblad som arbetsmetoder för att ta fram dem. Det finns därför ett uttalat behov av att standardisera såväl framtagning som presentation av data i elementblad. Syftet med detta examensarbete har varit att utveckla och testa en effektiv arbetsprocess för att tidsätta och ta fram lättförståeliga elementblad med stöd av digitala underlag. Därmed har en koppling mellan processerna för digital provmontering och framtagning av elementblad skapats. Ett förslag till arbetsmodell för framtagning av elementblad för chassimonteringen presenteras. I denna används de digitala underlagen både vid tidssättning med hjälp av standardtidssystem och för framtagning av bilder för beskrivning av monteringsoperationerna. Arbetsmodellen är anpassad till de applikationer som Scania använder idag. Resultatet av den enkät där arbetsprocessens effektivitet utvärderats visar att den har potential att leverera elementblad av högre kvalité än dagens process. / Scania operates in a global market and has manufacturing at multiple sites worldwide. Independently of where they are made, a consistently applied standardized work is a fundamental necessity to ensure the quality of their products. Assembly instructions – or element sheets as they are called at Scania, play an important role in communicating this standardized work across the entire company. The so called standardized work is relatively well established amongst production units which assembles the same type of key component, but in a wider perspective there are differences in presentation of the data in element sheets as well as the work methods used to create them. This evokes the need to standardize the creation process as well as how the data of the element sheets are presented. The purpose of this study has been to develop and test an efficient work process where digital models are used for creating element sheets with a high level of comprehensibility, and in addition for conducing predetermined motion time study (PMTS) of the activities included in them. Thus, a link between digital test assembly (DTA) and the process for creating element sheets has been established. A proposal for a work process for the creation of element sheets for the chassis assembly is presented. In this, the use of digital models while conducting PMTS as well as when extracting illustrations for describing assembly operations are fundamental. The work process is adapted to fit Scania’s existing software portfolio. The result of the survey where the work process efficiency was evaluated showed that it has the potential to deliver element sheets with a higher quality than the process of today.
40

An approach for systematic process planning of gear transmission parts

Bagge, Mats January 2009 (has links)
The objective of this thesis is to find and develop methods that enhance and support the creation of evolvable master process plans with possibilities to challenge productivity and meet changing design requirements. The condition for achieving this is primarily that both the fundamental thinking and the results behind a process plan can be described. How should this be done? The focus is laid on process planning of gear transmission parts for heavy vehicles like trucks and coaches. Process planning is the activity where design and manufacturing are brought together with the common target to achieve both a competitive product and production process. There are many factors that influence the process planner when a new product or process shall be introduced for production. Process planning is, in most cases, performed by an experienced, skilled person but without any defined methodology or way of working. Much of the process planning is based on the retrieval of solutions already used. Much research effort has been devoted to developing systems for computer-aided process planning (CAPP). Yet CAPP systems have not been accepted and spread over a wide front within the manufacturing industry, much because of the functional incompleteness combined with the difficulties of adopting knowledge and changing requests. A method for systematic process planning is proposed as a way to perform and describe the procedure of creating a process plan. The method facilitates the interpretation and understanding of the plan, not only immediately for the process planner responsible, but also for designers, engineers, researchers and other interest groups involved in a manufacturing process. In the last chapter is a case study regarding manufacturing of a bevel gear pinion presented to exemplify use of the proposed method for systematic process planning. / KUGG

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