1,721,276 research outputs found
Machining and tolerances in a flexible and integrated manufacturing context
No full textPart tolerance design is the process to define the optimal values of part functional characteristics. It is a complex and iterative process because technological and economical parameters should be considered together with functional requirements. It involves the plan of the most convenient manufacturing process allowing to obtain the specified functional requirements. This means to consider different process macro cycles able to produce the part with the specified functional tolerances and, then, to make a cost based choice. However, the manufacturing processes introduce a dimensional and geometrical variability that should be correlated with the part functional tolerances. This work tackles the problem of manufacturing feasibility of assigned part tolerances. It considers separately the manufacturing variability and the functional specifications and it tries to find relationships between them. It takes into consideration the possible correlation among functional requirements. An assembly that is widely used to test the performances of different design methods represent the case study. This work is the first step towards the development of a module to support the designer during the definition of a functional project. This module belongs to a flexible and integrated environment that orients and controls manufacturing
Robust Design of a Fixture Configuration in the Presence of form Deviations
Full text linkAbstractDuring machining, the tool path is defined with respect to the workpiece reference frame. The workpiece's boundary surfaces have form deviations, and the geometry and the position of the locators are imperfect. The resulting misalignment produces geometrical errors in the features machined on the workpiece.The main purpose of this work is to investigate how the geometric errors of a machined surface are related to the main sources of the locator errors and to the form deviations of the workpiece. A mathematical framework is presented for an analysis of the relationship among the manufacturing errors, the part form deviations, and the locator errors
Manufacturing Signature for Tolerance Analysis
Full text linkEvery manufacturing process leaves on the surface a signature, i.e., a systematic pattern that characterizes all the features machined with that process. The present work investigates the effects of considering the manufacturing signature in solving a tolerance stack-up function. A new variational model was developed that allows to deal with the form tolerance. It was used to solve a case study involving three parts with or without considering the correlation among the points of the same surface due to the manufacturing signature. A sensitivity analysis was developed by considering different values of the applied geometrical tolerances
Analytical approach to estimate the minimum 3D position deviation of a hole due to fixturing
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