Ces travaux proposent une méthode d’assistance à la sélection des techniques d’assemblage et à l’allocation de tolérances sur les écarts géométriques des composants dans le cadre de l’assemblage de structures aéronautiques composites. Cette méthode consiste à formuler et à résoudre un problème d’optimisation multiobjectif afin de minimiser un indicateur de cout et un indicateur de non-conformité des structures assemblées. L’indicateur de coût proposé prend en compte le coût associé à l’allocation des tolérances géométriques ainsi que le coût associé aux opérations d’assemblage. Les indicateurs de non-conformités proposés sont évalués à partir des probabilités de non-respect des exigences géométriques sur les structures assemblées. Ces probabilités sont évaluées en propageant les tolérances géométriques allouées et les dispersions des techniques sélectionnées au travers d’une fonction appelée Relation de Comportement de l’assemblage (RdCa). Dans le cas de l’assemblage de structures aéronautiques composites, des exigences peuvent porter sur les jeux aux interfaces entre composants. Dans ce cas, la RdCa est évaluée par la résolution d’un problème mécanique quasi-statique non-linéaire par la méthode des éléments finis. Un méta-modèle de la RdCa est construit afin de la rendre compatible avec les méthodes probabilistes utilisées pour évaluer la non-conformité. Finalement, la définition d’un modèle structuro-fonctionnel du produit et d’une bibliothèque de techniques d’assemblage permet de construire un avant-projet de gamme d’assemblage paramétrique. Ce paramétrage permet de formuler le problème d’optimisation multiobjectif résolu à l’aide d’un algorithme génétique. / The purpose of this PhD is to develop a method to assist assembly technique selection and component geometrical tolerance allocation in the context of composite aeronautical structure assembly. The proposed method consists in formulating and solving a multiobjective optimisation problem aiming at minimising a cost indicator and a non-conformity indicator. The cost indicator account for both the cost involved by the geometrical tolerance allocation and the cost associated with the assembly operations. The proposed non-conformity indicators are evaluated according to the probabilities of non-satisfied requirements on the assembled structures. These probabilities are computed thanks to Geometrical Variation Propagation Relation (GVPR) that expresses the characteristics of the product as a function of the geometrical deviation of the components and the dispersion occurring during the assembly. In the case of composite aeronautical structures, the product characteristics can be gaps at interfaces between components. In this case, the GVPR is evaluated by solving a non-linear quasi-static mechanical problem by the mean of the finite element method. A metamodel of the GVPR is built in order to reduce the computing time and to make it compatible with the probabilistic methods used to evaluate the non-conformity. Finally, the use of a structure-functional model of the product together with an assembly technique library allows defining a parametric assembly process plan. The multiobjective optimisation problem built thanks to set of parameters defining the assembly process plan is solved using a genetic algorithm.

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.

Este trabalho teve como objetivo propor uma metodologia para otimizar o planejamento de processos de montagem final da indústria automotiva. A metodologia proposta foi elaborada com base na revisão bibliográfica e no Mapeamento de Processos Críticos da atividade de planejamento de processos de montagem final durante o desenvolvimento de produtos, tendo como referência a subsidiária brasileira de uma montadora. A metodologia proposta consiste em aplicar o PFMEA (Process Failure Mode and Effect Analysis) associado às seguintes ferramentas de qualidade: Brainstorming, Benchmarking, Lições Aprendidas, Sistemas À Prova de Erros, Diagramas de Causa e Efeito e 5 Por Quês. Neste trabalho foi adotada a realização de uma pesquisa explicativa com metodologia de pesquisa-ação. Foram criados procedimentos para que a metodologia proposta fosse aplicada experimentalmente na unidade de análise deste trabalho. A fase de coleta de dados foi feita através de três estudos de caso. Com base nos resultados obtidos, foram analisados os benefícios da aplicação da metodologia proposta e os procedimentos para formar equipes para realizar estudos de PFMEA, no contexto da Engenharia Simultânea. Foi observado que a aplicação da metodologia proposta por este trabalho proporcionou importantes benefícios para o planejamento de processos de montagem final, a especificação técnica de equipamentos de montagem e o desenvolvimento de produtos. / The objective of this work was to propose a methodology to optimize the general assembly process planning of automotive industry. The proposed methodology was elaborated based on bibliographic revision and a Critical Process Mapping regarding general assembly process planning activity during product development, referring to a Brazilian automaker subsidiary. The proposed methodology consists in applying PFMEA (Process Failure Mode and Effect Analysis) associated with the following quality tools: Brainstorming, Benchmarking, Lessons Learned, Error Proof Systems, Cause and Effect Diagrams, and 5 Why’s. Explicative research with action research method was adopted in this work. Procedures were created to experimentally apply the proposed methodology to the analysis unit of this work. The data collect phase was performed through three case studies. Based on the experimental results, advantages of the proposed methodology and PFMEA team formation were analyzed, in the context of Simultaneous Engineering. It was observed that the implementation of the proposed methodology provided important benefits to general assembly process planning, assembly equipment technical specification and product development.

Este trabalho teve como objetivo propor uma metodologia para otimizar o planejamento de processos de montagem final da indústria automotiva. A metodologia proposta foi elaborada com base na revisão bibliográfica e no Mapeamento de Processos Críticos da atividade de planejamento de processos de montagem final durante o desenvolvimento de produtos, tendo como referência a subsidiária brasileira de uma montadora. A metodologia proposta consiste em aplicar o PFMEA (Process Failure Mode and Effect Analysis) associado às seguintes ferramentas de qualidade: Brainstorming, Benchmarking, Lições Aprendidas, Sistemas À Prova de Erros, Diagramas de Causa e Efeito e 5 Por Quês. Neste trabalho foi adotada a realização de uma pesquisa explicativa com metodologia de pesquisa-ação. Foram criados procedimentos para que a metodologia proposta fosse aplicada experimentalmente na unidade de análise deste trabalho. A fase de coleta de dados foi feita através de três estudos de caso. Com base nos resultados obtidos, foram analisados os benefícios da aplicação da metodologia proposta e os procedimentos para formar equipes para realizar estudos de PFMEA, no contexto da Engenharia Simultânea. Foi observado que a aplicação da metodologia proposta por este trabalho proporcionou importantes benefícios para o planejamento de processos de montagem final, a especificação técnica de equipamentos de montagem e o desenvolvimento de produtos. / The objective of this work was to propose a methodology to optimize the general assembly process planning of automotive industry. The proposed methodology was elaborated based on bibliographic revision and a Critical Process Mapping regarding general assembly process planning activity during product development, referring to a Brazilian automaker subsidiary. The proposed methodology consists in applying PFMEA (Process Failure Mode and Effect Analysis) associated with the following quality tools: Brainstorming, Benchmarking, Lessons Learned, Error Proof Systems, Cause and Effect Diagrams, and 5 Why’s. Explicative research with action research method was adopted in this work. Procedures were created to experimentally apply the proposed methodology to the analysis unit of this work. The data collect phase was performed through three case studies. Based on the experimental results, advantages of the proposed methodology and PFMEA team formation were analyzed, in the context of Simultaneous Engineering. It was observed that the implementation of the proposed methodology provided important benefits to general assembly process planning, assembly equipment technical specification and product development.