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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.
1

Concept Development of a Recliner Mechanism for a Car Seat

Mora Fontelles, Alejandro January 2016 (has links)
Nowadays, there are more and more regulations regarding the emissions of greenhouse gases. The automotive sector is directly affected by new standards enacted by the National Highway Traffic Safety Administration (NHTSA) in America and by European regulations in Europe that are forcing car manufacturers to produce more efficient cars. Different ways exist to increase the efficiency of a car and thus reduce the CO2 emissions. One known strategy to improve fuel economy in vehicles is by weight reduction. Consequently, car manufacturers are seeking out new companies that can supply them with lighter car components. Here is where VA Automotive enters the picture, as a car seat manufacturer that is willing to improve their product by reducing the weight of its various components. This study deals with the development of a new recliner design that demonstrates improvements in terms of weight, size and performance compared to the current solution used at VA Automotive. A common product development methodology has been developed to reach the final recliner design which went through the following steps. First of all, a benchmarking technique was adopted to gather as much data as possible from the competitors’ products. Then, a list of target values for the product specifications was defined as a guideline for the development of the product. The next step was to generate several concepts of recliner’s mechanism that were suitable to improve the design from VA Automotive. After that, a Pugh decision matrix was used to select the best alternative between the concepts generated previously. The optimal concept was further developed by generating four design alternatives that were analyzed in terms of manufacturing, assembly, weight and size by using the Lucas DFMA method. Finally some simulations were run for one of the designs in order to check the structural performance of the mechanism and prove this way that the new recliner design meets the requirements. When comparing the new design alternatives with the design from VA Automotive, it was noticed that all the new designs except one presented a lower manufacturing cost index. Moreover, for all of the alternatives of the new recliner design, the weight was reduced by more than 56% compared to the recliner used at VA Automotive. Finally, by means of FEM simulations it was demonstrated that by choosing the right material the new recliner design was able to meet the structural requirements.
2

Appropriate instructions for manual assembly workers in industrial manufacturing settings: factors to consider

Kuipers, Nathanaël January 2020 (has links)
Manual assembly workers have nowadays a much higher workload than before. Not only do they have to deal with many more product variants, but as aconsequence they also receive many more information signals that they have to act upon. This study focuses on the information assembly workers receive through visual instructions. By conducting a literature review in the domains of product development with focus on design for assembly, cognition related to informationin instructions and different instruction formats like paper, tablet, and augmented reality (AR), commonalities and differences could be identified. Assembly operations are generally divided in handling a part and joining a part, and instructions should inform the assembly worker about when what should be assembled where and how. Each of these aspects has an impact on the overall complexity of the assembly process. To realise which of these aspects is most critical for an assembly worker can be of help in creating and delivering effective, tailor made instructions. The main finding is that there is not a one size fits all solution when it comes to the effectiveness of instructions, but that the type of instructions and the way they are delivered should in the first place be adjusted to the complexity of the assembly operations and secondly - if possible - also adjusted to the experience of the worker. The outcomes mentioned in this document should help laying the foundation for rules and guidelines when it comes to manual assembly instructions and its factors to consider.
3

Produktutformning och materialval för formsprutning : beträffande polymera material / Product design and material selection for injection molding : concerning polymer materials

Johansson, Hanna, Sundin, Maria January 2015 (has links)
Formsprutning är en tillverkningsmetod somställer krav på produkters utformning. För att göra en lämplig ingötsplacering räcker inte alltid riktlinjer utan en produktspecifik analys kan vara nödvändig. Materialval kräver en tydlig kravspecifikation och kan med fördel göras i samråd med en materialexpert. Riktlinjer för Design for manufacturing and assembly inkluderar bland annat rekommendationer för formgivning. Detta kandidatarbete strävar efter att hjälpa produktutvecklare att tidigt i produktutvecklingsprocessen ta hänsyn till tillverkningsaspekter. Baserat på litteraturstudier, intervjuer och fallstudier har riktlinjer tagits fram för materialval, design for manufacturing and assembly och formgivning för formsprutning. Arbetet är avgränsat till att endast titta på formsprutningsbara termoplaster. Arbetet, som genomförts vid Linköpings universitet, är en del av projektet Säkra monteringsverktyg som resulterade i ett portabelt dödmansgrepp. Defallstudier som genomfördes inom projektetbehandlar värdering av koncept utifrån produktionsperspektiv, materialval och formsprutningsanalyser i programmet Moldflow. Arbetet resulterade i riktlinjer för applicering av metoden design for manufacturing and assembly, formsprutningsanpassning samt materialval. Fallstudien i Säkra monteringsverktyg utmynnade ien värdering av koncept utifrån produktionsaspekter, ett materialval baserat på projektets kravspecifikation och rekommendationer för produktens utformning med syfte att optimera dess tillverkning. En slutsats av arbetet är att produktionsanpassning av produktens utformning bör ske tidigt i utvecklingsprocessen. En annan slutsats är att besök i industrin, hos exempelvis ett formsprutningsföretag, leder till bättre förståelse av vilka krav som behöver uppfyllas för att en produkt ska vara möjlig att producera. Om simuleringsprogram för formsprutning finns bör det användas i kombination med riktlinjer för produktutformning. Ytterligare en slutsats som gjorts är att materialval underlättas genom tidig kontakt med materialleverantörer. Materialvalet baseras på kravspecifikationen och därför bör kraven tydliggöras och dess rimlighet kontrolleras innan materialvalet sker. / Injection molding is a manufacturing method that requires specific features to attain manufacturability. Gating suitability requires analysis and mere guidelines do not always provide the correct gate placement. Material selection requires a pronounced specification and is preferably supervised by an expert. Guidelines concerning design for manufacturing and assembly include, among other things, recommendations directly affecting the shape of the product. The aim for this bachelor thesis is to aid product developers and designers in taking manufacturing aspects into account early in the product development process. This is achieved by providing them with guidelines regarding material selection, injection molding, as well as design for manufacturing and assembly. The thesis is limited to thermoplastic materials suitable for injection molding and its results are based off thorough literature research, interviews and case studies. This bachelor thesis project, which is conducted at Linköping University,is a part of a project calledSafe manual assembly tools, and the resulting portable enabling device developed in Safe manual assembly toolsis used as case studies in this thesis. The case studies include: evaluation of concepts concerning manufacturability; material selection; and injection molding analysis through the software Moldflow. The thesis results in guidelines concerning design for manufacturing and assembly, injection molding and material selection. The case study is requited with concept selection suggestions, a selection of material that meets the specification of requirements stated in Safe manual assembly tools and design recommendations that aim to improve the manufacturability of the concept. This bachelor thesis concludes that design alterations striving to meet requirements for manufacturability should be made early in the devolpment process. Visiting the polymer-based product manufacturing industry offers better insight into which requirements that need to be fulfilled to make a product producible. Injection molding simulation software, if such is available, should be used in combination with design guidelines.The thesis also concludes that material selection is simplified through early contact with suppliers of material. Material selection is based off the specification of requirements and therefore requirements specified in the specification should be clarified and have their plausibility confirmed before the selection takes place.
4

[en] INFORMATION DELIVERY MANUAL CONSIDERING MANUFACTURING AND ASSEMBLY OF STRUCTURAL ELEMENTS IN REPLICABLE BUILDING PROJECTS / [pt] PROPOSTA DE FLUXO DE TRABALHO BIM CONSIDERANDO FABRICAÇÃO E MONTAGEM DE ELEMENTOS ESTRUTURAIS EM PROJETOS DE EDIFICAÇÕES REPLICÁVEIS EM ESCALA

ALESSANDRA S R DI SAN SECONDO 03 December 2020 (has links)
[pt] A necessidade de aumentar a produtividade no setor da construção civil estimulou investimentos em soluções digitais e a incorporação de princípios de manufatura na cadeia construtiva. A implementação de elementos estruturais padronizados fabricados fora do canteiro de obra é considerada uma prática válida para atingir este objetivo. O projeto para fabricação e montagem é um conceito que envolve diretrizes a serem consideradas no desenvolvimento do projeto, cuja finalidade é facilitar a fabricação e montagem de componentes. A metodologia BIM pode incorporar análises de planejamento e construtibilidade para apoiar a tomada de decisão no contexto de construções replicáveis em escala de concreto armado. A presente investigação inclui uma revisão sistemática da literatura que orientou a pesquisa. Com base na SLR (Structured Literature Review), foi desenvolvido um Manual de Entrega de Informações que propõe um novo fluxo de trabalho no qual os estudos de planejamento construtivo e princípios de fabricação e montagem são agregados nos estágios iniciais do projeto para aproveitar a colaboração intrínseca da metodologia BIM. Para ilustrar o fluxo de trabalho proposto no IDM (Information Delivery Manual) desenvolvido é apresentado um experimento de um complexo de escolas. As informações do modelo parametrizado serviram como dados de entrada para as análises realizadas permitindo assim que pudessem ser comtemplados diferentes cenários de soluções estruturais. Os resultados obtidos pelo experimento indicam que a consideração de elementos de concreto pré-fabricado nem sempre vai contra os interesses econômicos, práticos e estéticos. Por fim, as análises de planejamento e construtibilidade são parâmetros importantes nas tomadas de decisão para aprimorar a identificação de oportunidades de melhorias no projeto e potencializar a eficiência de trabalho no canteiro de obra. / [en] The need to increase the civil construction sector stimulates investments in digital solutions and manufacturing principles in construction industry. The employment of standardized structural elements manufactured off-site construction, such as structural precast element, is considered a valid practice to achieve this purpose. The Design for Manufacturing and Assembly (DFMA) is a concept that involves guidelines considered in the development of the project and has the objective to facilitate the manufacturing and assembly of a product or component. Building Information Modeling (BIM) methodology can incorporate planning and constructability analysis to support decision making in the context of scalable and replicable concrete building projects. The present investigation includes a Structured Literature Review (SLR) that guided the research. Based on the SLR, an Information Delivery Manual (IDM) was developed to propose a new workflow in which the studies of construction planning and the application of manufacturing and assembly principles are considered in the early stages of design to take advantage of the collaboration intrinsic to the BIM methodology. An experiment of a school complex is presented to illustrate the workflow proposed in the developed IDM. The parametric model information was the key input to run analyzes in different structural solutions scenarios. The results indicated that the consideration of precast concrete elements does not always contradict economic, practical and aesthetic interests. Finally, planning and constructability analyzes are important parameters in decision-making, enhancing the recognition of opportunities for improvement in the project and increasing the efficiency of work in the construction site.

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