Optimisation de l’allocation des tolérances pour les gabarits d’usinage

Abstract

This Master’s thesis presents a wrap-up of an industrial research project under a theme related to the project CRIAQ MANU-1707_TRL4+ entitled:’ Creation of demonstrating strategies of hybrid conception and manufacturing for aerospace tooling’. The main objective of the project is to reduce the costs of tool designing and manufacturing for aeronautical components. Several themes are addressed by the different participating industrial partners. Thus, the design procedures, the materials used and the manner of manufacturing the tooling are studied. More specifically, within the framework of the machining fixture design, optimizing the allocation of tolerances for machining fixtures has an important economic impact. Therefore, a decision support tool for the machining fixture designer will have a significant advantage during the design phase. This is precisely the subject of this research project. A model that allows the fixture designer to estimate the geometric errors of the features to be machined, upstream of machining process, is presented. The machining accuracy of datum-related toleranced features under the effect of locating errors (which are influenced by the tolerances assigned to locators and by the irregularities of the workpiece feature which mates with the fixture) and the rotational and translational errors of the tooltip is evaluated. The work is based on the theory of the Small Displacement Torsor (SDT) and on the concept of the calculation of the geometric variations according to the standards ASME Y14.5 and Y14.5.1M. The model is validated on several case studies provided by the industrial partner of the project. The final solution is delivered in the form of a GUI (Graphical User Interface) application facilitating the use of the proposed solution.

Date	19 May 2020
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Antoine Tahan (Supervisor) & Nabil Abacha (Co-supervisor)