1,721,110 research outputs found
Shape evaluation procedure for free form surfaces
No full textIn this study a series of procedures were implemented to compare acquired surfaces with the nominal data or to directly compare different scanned surfaces. In particular a morphological evaluation algorithm based on the Extended Gaussian Curvature (EGC) and a method to compare features based on aggregate normal orientation are presented. To perform the comparing feature method a simple procedure for segmentation was developed. The main characteristic of the two methods is robust behavior referring to the scan orientation. The procedures were implemented as software modules in a graphic environment
Application of Reverse Engineering techniques for surface quality control of automotive components
No full textThe aim of this work concern the analysis of the effectiveness of Reverse Engineering methods (scanning and processing data) for the purpose of evaluating and controlling the geometrical characteristics and surface quality of automotive body components. Evaluation of the surface characteristics of the part has been conducted utilizing reverse engineering instead of the traditional point-by-point measurement techniques. In particular, the study of the models focused on the behavior of the curvature, obtained on sections of the surfaces. The scatter present in data obtained from different scannings and other kinds of imprecision arising from the processing techniques employed create many problems in the assessment of surface quality. This study presents an original methodology for a benchmark test between different scanning methods, the benchmark is done by means of some aluminum alloy test plates with known, established surface features. By the acquisition of the test plates we could evaluate the different capability in revealing local curvature and other types of defects
Metodologie per la misura ed il controllo di stampi con tecniche di Reverse Engineering
No full textIl presente lavoro propone una procedura per il controllo geometrico-dimensionale di stampi e pezzi che, utilizzando strumentazioni non convenzionali per tali scopi, si basa sulla creazione di un modello software dell’oggetto da misurare mediante la acquisizione di dati geometrico dimensionali con tecniche di scansione. Tale procedura permette: da una parte di effettuare misure puntuali sul modello acquisito; dall’altra di confrontare il modello così ottenuto con un modello matematico precedentemente creato ed usato come riferimento; essa si presta pertanto ad essere applicata per ottenere controlli diversi dal momento che si possono confrontare progetto, stampo ed oggetto realizzato. Il lavoro ha consentito inoltre di mettere a confronto sistemi di scansione basati su diverse tecnologie così da poterne valutare la loro effettiva applicabilità nel controllo dimensionale e di forma di stampi e pezzi di piccola, media e grande dimensione. L’attività è stata svolta nell’ambito Programma di Ricerca Nazionale “Tecnologia di Resin Transfer Moulding (RTM) per Infusion per componenti in materiale composito di grandi dimensioni
Application Of Reverse Engineering and Analysis Techniques for Surface Quality Control of Automotive Components
No full textThe aim of this work concern the analysis of the effectiveness of Reverse Engineering methods (scanning and processing data) for the purpose of evaluating and controlling the geometrical characteristics and surface quality of automotive body components. Evaluation of the surface characteristics of the part has been conducted utilizing reverse engineering instead of the traditional point-by-point measurement techniques. In particular, the study of the models focused on the behavior of the curvature, obtained on sections of the surfaces. The scatter present in data obtained from different scannings and other kinds of imprecision arising from the processing techniques employed create many problems in the assessment of surface quality. This study presents an original methodology for a benchmark test between different scanning methods, the benchmark is done by means of some aluminum alloy test plates with known, established surface features. By the acquisition of the test plates we could evaluate the different capability in revealing local curvature and other types of defects
Geometrical inspection of designed and acquired surfaces
No full textIn this study a series of procedures were implemented to compare acquired surfaces with the nominal data or to directly compare different scanned surfaces. In particular a morphological evaluation algorithm based on the extended Gaussian curvature (EGC) and a method to compare features based on aggregate normal orientation are presented. To perform the comparison between the features a simple procedure for segmentation was developed. The main characteristic of the two methods is a robust behavior referring to the scan orientation. The procedures were implemented as software modules in a graphic environment
Automated characterization of the material removal rate in laser manufacturing of TiAI6V4 and inconel 718
No full textIn this paper a system for the automatic determination of the material removal rate during laser milling process is presented. ”Laser milling” can be defined as an engraving process with a strictly controlled penetration depth. In industrial applications, when a new material have to be machined or a change in the system set-up occur the user has to perform a time-consuming experimental campaign in order to determine the correlation between the material removal rate and the process parameters. In these cases the numerical models present some limits due to the elevated calculation time requested to simulate the laser milling of industrial features. In the proposed system, based on a regression model approach, the empirical coefficients, that provide the material removal rate, are automatically generated by a specific software according to the different materials that have to be processed. A description of the automated method and the results obtained in engraving TiAl6V4 and Inconel 718 superalloy with a fiber laser are presented. The system can be adapted to every combination of material/laser source
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Hybrid Modeling of the Vertical Z Axis in an HSM Machining Center
No full textThe paper focus on the dynamical stability of a Z axis of machine center for high speed machinin
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