Intégration Produit / Process par les concepts d'activités et de caractéristiques clés - Application à l'optimisation de l'allocation des tolérances géométriques

Imperfections due to the manufacturing process and in its resources areresponsible for the deterioration of functional characteristics and as a consequence, theproduct quality. In order to ensure a certain quality level, the tolerance synthesis tries todetermine admissible limits of workpiece and assembly characteristics. Tolerance synthesisor tolerance allocation, which belongs to the detailed product design phase, is an importantstep of the design process as it hugely impacts design of manufacturing process, productmanufacturing and its control. Consequently it is important to take into account, during thequantification of functional tolerances, their impact on both cost and quality of themanufactured products. These two notions are considered as antinomic. The aim of theproposed approach is to find the tolerance allocation providing the best balance betweenfunctional performances and manufacturing cost. This solution is based on the concept ofKey Characteristics, created by Boeing. It is associated with an activity approach inspiredby the Activity Based Costing method and adapted to the needs of the manufacturingprocess selection and analysis. In order to quantify this balance, this work suggests thedefinition of a performance indicator evaluating an allocation: the cost weighted quality.Moreover, this thesis describes an original solution for the optimisation of toleranceallocations: the Activity Based Tolerance Allocation (ABTA). This solution was developedusing several computer prototypes to validate the solutions, concepts and methodscomposing it.