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A comparison between a methodological statistical approach and a commercial software for evaluating tolerance chains
No full textThis paper reports two different approaches to the analysis of tolerance chains. A simple part is considered and a functional dimensioning scheme is described. Then, an analysis of the tolerances is performed with a commercial software package and with a methodological statistical procedure.
In particular, the procedure proposed can be summarised into two main steps. First, each single technological operation (for example, the drilling of a hole) is simulated by extracting, from a statistical distribution typical of the machine tool, the parameters characteristic of the manufacturing procedure. Then, a simulation is performed, to verify if the real features of the part can simultaneously fit the virtual gage. This method of acceptance/rejection of a part is according to the ISO/ASME standards and is representative of the real functional requirements of the part
Applicazione di una trasformata wavelet al riconoscimento di cricche e di difetti di saldatura
No full textValutazione di una procedura per lo studio delle tensioni residue con l'interferometria moirè e il metodo del foro
No full textA method with a statistical approach for the evaluation of tolerance chains
No full textIn this paper a procedure based on a statistical approach to manufacturing for the analysis of tolerance chains is reported. In particular, the proposed approach can be summarised into two main steps. First, each single technological operation (for example, the drilling of a hole) is simulated by extracting, from a statistical distribution typical of the machine tool, the parameters characteristic of the manufacturing procedure. Then, a simulation is performed, to verify if the real features of the part can simultaneously fit the virtual gage. This method of acceptance/rejection of a part is according to the ISO/ASME standards and is representative of the real functional requirements of the part
Calibri virtuali per tolleranze con modificatore di massimo materiale
No full textIn this paper a soft gage is built for checking the tolerances of a cylindrical
feature on a plate controlled by three datum reference planes. It is verified that the
points of the feature lay within the boundary of a virtual gage, which is represented
as the locus of the inner/outer points of a circle for a cylindrical feature (holes and
pins) and as the locus of the inner/outer points of two parallel segments for a feature
composed by two opposite faces (slots and tabs).
We report the algorithms, in part updated from previous papers, and an
application to a plate with three datum reference planes and with a hole qualified by
a position tolerance. Unlike in the previous work, in this application we consider the
tolerance with the MMC modifier. The results obtained are compared and discussed
to establish which ones better correspond to the real assembly of the part
Un approccio Problem Solving alle tolleranze dimensionali e geometriche
No full textIn this paper we propose a problem solving approach to the dimensional and
geometric tolerances. This approach starts from simple geometrical remarks
concerning the functional/ assembly characteristics of a part. It assigns the geometric
tolerances to the features by a method that connects the degrees of freedom to the
measurements. For instance, the contact of a face on a plane, which cancels three
degrees of freedom, allows the measurement of the forbidden translation (distance of
a point, an axis, or a plane from the contact plane of the face) and the measurements
of the forbidden rotations (angles between an axis or a plane and the contact plane of
the face). Points, axes and planes are associated with features: a point to a spherical
feature, an axis to a hole/shaft feature, a plane to a slot/tab feature or to a face. We
have chosen the envelope mode to avoid the introduction of the spines related to the
determination of central lines and median surfaces
Automazione in fotomeccanica e sua applicazione alla meccanica dei materiali: rassegna delle attività svolte presso l'Università di Cagliari
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