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Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAMElmubarak, Mona Dr. January 2018 (has links)
Magister Scientiae Dentium - MSc(Dent) / BACKGROUND: Plaster models form an integral part of the traditional orthodontic
records. They are necessary for diagnosis and treatment planning, case presentations
as well as for the evaluation of treatment progress. The accuracy of the measurements
taken for space assessment is crucial prior to treatment planning. The introduction of
digital models overcomes some problems experienced with plaster models. Digital
models have shown to be an acceptable alternative for plaster models.
AIM: The aim of the study was to determine the accuracy of traditional measurement
techniques when compared to the CAD/ CAM measurements in the assessment of
tooth widths and arch perimeter from plaster models.
METHOD: The mesio-distal tooth widths and arch perimeter of thirty archived plaster
models were measured using a digital caliper to the nearest 0.01 mm and divider to
the nearest 0.1 mm. Corresponding digital models were produced by scanning them
with a CAD/CAM (InEos X5) and space analysis completed by measurements using
InEos Blue software. Measurements were repeated after 1 week from the initial
measurement. The methods were compared using descriptive analysis (mean
difference and standard deviation).
RESULTS: The operator reliability was high for digital models as well as the plaster
models when the measurement tool was the digital caliper (analyzed using the
Pearson correlation coefficient in the paired t-test). The mean values of tooth widths
measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (±
0.04) and 7.11 (± 0.04). There was a significant difference between the measurements
made by the CAD/CAM and the divider. Additionally significant differences between
the measurements by digital caliper and divider measurements (p < 0.05) were
observed. No significant difference was found when comparing CAD/CAM to digital
caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the
divider, but the measurements completed with the digital caliper had the highest
correlation with the CAD/CAM. The difference was not significant between the
aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed
no statistical significant difference between CAD/CAM, digital caliper and divider (p
< 0.05).
CONCLUSION: Archived plaster models stored as records can be converted to digital
models as it will have the same accuracy of measurements. The value of doing a space
analysis with the CAD/CAM system can be performed with similar reliability on the
digital models as a caliper on plaster models.
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Caracterização de blocos sinterizados à base de CoCrMo visando a obtenção de próteses odontológicas por fresagem CAD/CAM / Characterization of Co-Cr-Mo sintered blocks in order to obtain dental prostheses by prototyping CAD/CAMBruno Xavier de Freitas 19 December 2016 (has links)
Estudou-se a caracterização de blocos sinterizados à base de Co-Cr-Mo visando a obtenção de próteses odontológicas por fresagem CAD/CAM. O processo de sinterização foi estudado e ocorreu através do transporte difusional de massa e calor no estado sólido, denominado sinterização no estado sólido. Esse fenômeno produz uma forte união entre as partículas devido ao transporte de massa, em escala atômica, sob condições controladas de tempo, temperatura e atmosfera. Foram realizadas sinterizações interrompidas a 800, 1000, 1200 e 1300°C nos tempos de 15 minutos, 1 hora e 4 horas. A liga foi caracterizada nas condições recebida e sinterizadas em termos de composição química, propriedades mecânicas e caracterização microestrutural. Para isto, utilizou-se fluorescência de raios X, dilatometria, ensaios de Arquimedes, ensaios de dureza, ensaios de compressão, microscopia eletrônica de varredura (MEV), microscopia óptica e microanálise eletrônica dispersiva (EDS). Os resultados composicionais indicam que a liga se encontrava dentro da faixa de composição química estabelecida pelo manual do fabricante e pela norma ASTM 1537. As partículas analisadas na condição pré-sinterizada exibiram formato esférico, indicando uma provável utilização de pós atomizados. A estimativa do levantamento da distribuição do tamanho das partículas foi realizado utilizando o programa de computador ImageJ, e a distribuição foi caracterizada como assimétrica positiva. O material no estado recebido se apresentou monofásico. A fase presente encontrada foi ?Co com estrutura cristalina CFC. Em contrapartida, as amostras sinterizadas apresentaram porções de fase ?Co, com estrutura cristalina hexagonal, fase esta formada a partir da transformação ?Co <-> ?Co, na qual, a energia armazenada na forma de defeitos é a força motriz da transformação. E sugere que a transformação ocorreu durante resfriamento. A amostra sinterizada por quatro horas em 1200°C apresentou-se no estágio final de sinterização, dado que os poros encontrados tinham aspecto arredondado e com densificação maior que 90%. Os resultados de compressão indicam tensão média de ruptura de 2523 ± 168 MPa. / This work studied the characterization of Co-Cr-Mo sintered blocks in order to obtain dental prosthesis by prototyping CAD/CAM. The sintering process was studied through diffusional mass transport in solid state, termed solid state sintering. This phenomenon produces a strong bond between the particles due to mass transport, at the atomic scale, under controlled conditions of time, temperature and atmosphere. The interrupted sintering was performed at 800, 1000, 1200 and 1300 ° C in times to 15 minutes, 1 hour and 4 hours. The alloy was characterized in conditions as received and sintered in terms of chemical composition, mechanical properties and microstructural characterization. For this, we used X-ray fluorescence, dilatometry, Archimedes tests, hardness tests, compression tests, scanning electron microscopy (SEM), optical microscopy and dispersive electron microanalysis (EDS). The results indicate that the alloy was within the chemical composition range established by the manufacturer and ASTM 1537. The particles analyzed in the pre-sintered condition showed spherical shape, indicating a likely use of atomized powders. The estimate of the particle size distribution was performed using ImageJ software, and the distribution is characterized as positive asymmetric. The samples in the received state were monophasic. This phase was found ?Co with FCC crystal structure. On the order hand, the sintered samples showed ?Co phase portions with hexagonal crystal structure, phase formed from the transformation ?Co <-> ?Co, in which the energy stored in the form of defects is the driving force of transformation and suggests that transformation occurred during the cooling. Sample sintered during four hours at 1200°C was in the final stages of sintering, since the pores were found aspect rounded and densification above 90%. The compression results indicate rupture stress at 2523 ± 168 MPa.
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Célula robótica industrial : aplicação de ferramentas CAD/CAM na programação de robôsRodrigues, Nuno Ferreira January 2011 (has links)
Tese de mestrado integrado. Engenharia Mecânica. Universidade do Porto. Faculdade de Engenharia. 2011
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Der Einfluss von Knochenrekonstruktionstechniken auf die implantologische Rehabilitation bei Kontinuitätsdefekten des Unterkiefers / Continuity defects of the mandible: Comparison of three techniques for osseous reconstruction and their impact on implant loadingOkcu, Yunus Dr. 19 September 2019 (has links)
No description available.
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Automated feature recognition system for supporting engineering activities downstream of conceptual design.Jones, Timothy, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2007 (has links)
Transfer of information between CAD models and downstream manufacturing process planning software typically involves redundant user interaction. Many existing tools are process-centric and unsuited for selection of a "best process" in the context of existing concurrent engineering design tools. A computer based Feature-Recognition (FR) process is developed to extract critical manufacturing features from engineering product CAD models. FR technology is used for automating the extraction of data from CAD product models and uses wire-frame geometry extracted from an IGES neutral file format. Existing hint-based feature recognition techniques have been extended to encompass a broader range of manufacturing domains than typical in the literature, by utilizing a combination of algorithms, each successful at a limited range of features. Use of wire-frame models simplifies product geometry and has the potential to support rapid manufacturing shape evaluation at the conceptual design stage. Native CAD files are converted to IGES neutral files to provide geometry data marshalling to remove variations in user modelling practice, and to provide a consistent starting point for FR operations. Wire-frame models are investigated to reduce computer resources compared to surface and solid models, and provide a means to recover intellectual property in terms of manufacturing design intent from legacy and contemporary product models. Geometric ambiguity in regard to what is ?solid? and what is not has plagued wire-frame FR development in the past. A new application of crossing number theory (CNT) has been developed to solve the wire-frame ambiguity problem for a range of test parts. The CNT approach works satisfactorily for products where all faces of the product can be recovered and is tested using a variety of mechanical engineering parts. Platform independent tools like Extensible Mark-up Language are used to capture data from the FR application and provide a means to separate FR and decision support applications. Separate applications are composed of reusable software modules that may be combined as required. Combining rule-based and case-based reasoning provides decision support to the manufacturing application as a means of rejecting unsuitable processes on functional and economic grounds while retaining verifiable decision pathways to satisfy industry regulators.
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Computer-aided design and manufacturing of tactile mapsChan, Chi-fung, January 2007 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
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The design capture system : capturing back-of-the-envelope sketchesHwang, Teng-shang 16 July 1990 (has links)
A system which allows the computer to capture sketches
made by a mechanical designer is described. The system not
only recognizes basic features as they are sketched, but it
also reasons the spatial relationships between features and
builds a high level abstract representation (feature model)
of the artifact. The temporal nature of the capture, one
feature at a time, serves to form a feature graph that
allows for parametric design. The system is composed of
three subsystems: a two-dimensional freehand sketching
subsystem¹ , a three-dimensional features recognition
subsystem, and a spatial reasoning subsystem.
The freehand sketching subsystem takes the user's
input sketching actions and interprets them as simple, two-dimensional
geometric elements, such as line segments,
circles, and ellipses, etc. The features recognition
subsystem interprets the collection of two-dimensional
geometric elements to extract three-dimensional information
from them and creates high level abstract representations,
features. The spatial reasoning subsystem finds
relationships between a new feature and existing features
and integrates features to form a single part.
The work of the Design Capture System is aimed at
capturing sketches of a specific application domain:
injected molding plastic parts. Twenty injected molding
plastic parts were collected and analyzed to understand the
distribution of features.
Isometric sketching is selected as the basic
constructing method for the system. The processes of
freehand sketching and computer-aided drafting were studied
to find a better scheme for computer-aided sketching.
Conclusions are also presented.
¹The Freehand Sketching Subsystem was accomplished by
Roger Fang as a Master project in 1987 at the Department of
Mechanical Engineering, Oregon State University, Corvallis,
Oregon. / Graduation date: 1991
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Caracterización microestructural y mecánica de materiales en base a cerámica elaborados por la tecnología CAD-CAM para su utilización en prótesis odontológicaCadafalch Cabaní, Juan 07 May 2004 (has links)
Las necesidades estéticas actuales en Odontología hacen que el empleo de los composites y las porcelanas sea cada día más frecuente en la práctica diaria. En 1971 se introdujeron de forma experimental y teórica en Odontología las técnicas CAD-CAM (CAD= Computer Aided Design (Diseño asistido por ordenador) / CAM = Computer Aided Manufacturing (Fabricación asistida por ordenador). En 1980, Mörmann y Brandestini empiezan a trabajar en la aplicación clínica del CAD-CAM. De todos los sistemas de trabajo desarrollados hasta la fecha destacaremos el CEREC por ser el que hemos utilizado en nuestro estudio. Realizado por Mörmann y Brandestini en 1980, en 1989 llega a la entonces Escuela de Estomatología de la Universidad de Barcelona con los Profesores Cadafalch y Llombart, desarrollándose nuevas versiones actualizadas y perfeccionadas más adelante. Básicamente el sistema CEREC se compone de una cámara CCD para realizar la impresión óptica, un software que nos permite el diseño de la restauración sobre una pantalla, y una cámara de tallado, en la que podemos distinguir dos motores que mueven un disco y una fresa de diamante de forma independiente.La hipótesis de trabajo que se estableció fue que los tratamientos de acabado en la superficie de la cerámica mecanizada para CAD-CAM mejoran las propiedades mecánicas, y la suma de estos tratamientos aumenta la efectividad de los mismos.En cuanto a los objetivos generales, se pretende demostrar que los materiales cerámicos para CAD-CAM mejoran sus propiedades mecánicas con los tratamientos de acabado a nivel de la superficie externa de los mismos (pulido y/o glaseado).
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The ITL programming interface toolkitRandrianarivony, Maharavo 27 February 2007 (has links) (PDF)
This document serves as a reference for the beta version of our evaluation
library ITL. First, it describes a library which gives an easy way for
programmers to evaluate the 3D image and the normal vector corresponding to
a parameter value which belongs to the unit square. The API functions which
are described in this document let programmers make those
evaluations without the need to understand the underlying CAD complica-
tions. As a consequence, programmers can concentrate on their own scien-
tific interests. Our second objective is to describe the input which is a set
of parametric four-sided surfaces that have the structure required by some
integral equation solvers.
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A CAD/CAM system for sheet metal blanking dies黃啓榮, Wong, Kai-wing. January 1991 (has links)
published_or_final_version / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy
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