Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnologico / Made available in DSpace on 2016-01-08T16:48:25Z (GMT). No. of bitstreams: 1 97682.pdf: 3911601 bytes, checksum: 6824067500079bdff9476ec19fb63007 (MD5) Previous issue date: 1990 / Neste trabalho é abordado o problema específico da integração da programação NC a sistemas CAD e CAPP. Inicialmente, desenvolve-se um estudo dos conceitos e técnicas de projeto, planejamento do processo e fabricação auxiliadas por computador, analisando-se os principais aspectos envolvidos na integração CAD/CAPP/CAM. Este estudo serve de base para a proposta de uma solução particular, aplicada a operações de furação. A solução proposta, implementada sob a forma de um sistema informatizado, utiliza um CAD comercial para microcomputadores para entrada de dados geométricos. Os desenhos dos furos são criados com auxílio de programas paramétricos, incorporados a estrutura do CAD em questão. Os dados geométricos, tratados como formas à base de "patterns", baseados no conceito de macros e "features", são armazenados no modelo geométrico da peça e extraídos através de interpretação do arquivo gráfico no formato padrão IGES. Os dados tecnológicos necessários ao programa NC são fornecidos por um sistema CAPP desenvolvidos na própria UFSC. O sistema de programação, a partir da interpretação dos arquivos de dados geométricos e tecnológicos, provê soluções de seqüenciamento do processo e codificação do programa, com inserção automática dos valores dos parâmetros de corte, levando em consideração critérios de minimização do número de trocas de ferramentas e otimização de seus percursos.

Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro Tecnologico / Made available in DSpace on 2016-01-08T17:06:05Z (GMT). No. of bitstreams: 1 83267.pdf: 4466693 bytes, checksum: b05cac0dae6c66da123ca884fa76af4c (MD5) Previous issue date: 1991 / Este trabalho visa o desenvolvimento de um sistema gráfico interativo, denominado SAPRO vs CHAPAS (Sistema de Apoio à Produção Versão Corte de Chapas). O objetivo de tal sistema é possibilitar às indústrias nacionais do setor metal-mecânico, acesso às novas tecnologias de preparação de dados para corte de chapas. Todo o modelo conceitual do SAPRO consiste na observação de requisitos tecnológicos e computacionais dos sistemas CAD/CAM. O SAPRO tem como propósito prover o usuário de recursos tais que, a partir da concepção de uma peça mais restrições de produtividade, obtenham-se de forma rápida e precisa, os respectivos projetos técnico-mecânicos das peças e o encaixe destas peças sobre a chapa a ser trabalhada. O SAPRO também fornece, de forma automática, a programação NC responsável pela condução do processo de fabricação na máquina de corte. Relatórios contendo informações relevantes ao usuário podem ser gerados, segundo necessidades de cada indústria. Outro forte aspecto do SAPRO refere-se à valiosa contribuição técnica da empresa White Martins Soldagens, que veio solidificar a relação indústria-universidade, na procura de soluções nacionais.

Made available in DSpace on 2014-06-12T17:34:59Z (GMT). No. of bitstreams: 2 arquivo2004_1.pdf: 3200148 bytes, checksum: f3828ef94d92679f7e75b61c5527b68b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / No âmbito deste trabalho foi abordada a problemática da geração automática do código NC para o processo de usinagem por fresamento em 2 ½ eixos. Nele foi desenvolvida uma metodologia que visa auxiliar a obtenção dos parâmetros necessários para a construção do programa de comando numérico (código NC). Esta metodologia propõe desenvolver um sistema de reconhecimento geométrico. O sistema lê arquivos neutros como entrada e traduz a informação em um arquivo de informação de fabricação. A metodologia se divide nas seguintes partes a considerar: 1) Extrações das informações geométricas do CAD; 2) Determinação das seqüências de corte; 3) Otimização dos parâmetros de usinagem e 4) Geração do código NC propriamente dito. A extração das informações geométricas é realizada através de um programa computacional desenvolvido neste trabalho, que captura as informações de dois arquivos neutros em formato IGES, um constituindo a peça bruta e o outro constituindo a peça ser fabricada. A informação geométrica de contorno (B-rep) é então analisada, onde através de processamento, os dados são armazenados em uma estrutura de grafo. Com a estrutura de grafo montada, podem-se obter informações, através das quais o programa fornece com relativa versatilidade as seqüências de operações de corte, que deverão ser executadas para a fabricação da peça. Após o reconhecimento geométrico e o sequenciamento das operações é realizada a otimização das condições de corte e dos percursos das ferramentas para cada operação, os quais são obtidos considerando-se o critério de mínimo tempo total de fabricação por peça, ou seja, critério de máxima produção. O programa computacional, assim, gera automaticamente programas em linguagem de máquina (código NC), para posterior envio a uma máquina CNC. O programa computacional foi desenvolvido por programação orientada a objetos (OOP) e escrito em linguagem C++ tendo como domínio o campo de peças prismáticas de base poligonal que possam ser usinadas em uma fresadora ou centro de usinagem CNC

A software package and associated hardware have been developed which gives users of the ORAC CNC Training Lathe an easier and faster method of manufacturing on the lathe. The package, entitled ORACAP, uses the computing power of a mini-mainframe computer, a VAX 11/750, to assist in part design, program generation, program optimization, and program proving for the ORAC Lathe. The package is designed for users unfamiliar with computers such as students in an educational institute or workers in a production facility and uses command procedures to simplify the preparation and execution of the modules of the package. In addition to providing users with a valuable tool for manufacturing, ORACAP also gives users insight into the Computer Aided Design and Computer Aided Manufacturing methods used in industry, that is, it demonstrates the methods which allow production of a part from a very concise description of its geometry. Finally, ORACAP demonstrates the production advantages of a CAD/CAM system over conventional manufacturing methods for small to medium size batch production. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

OBJECTIVES: The objectives of this study was to determine the differences in failure load between cemented and fused machined veneers to zirconia while observing the effects of real time aging on failure load between cemented and fused machined veneers to zirconia. The study was to examine the differences in aging and fatigue resistance amongst a machined glass-ceramic veneer and a machined feldspathic porcelain veneer. MATERIALS AND METHODS: VITA In Ceram YZ zirconia blocks were used as a substructure framework for the three unit fixed partial denture. The veneering material was either milled IPS e.max CAD (glass-ceramic) or milled VITABLOCS Triluxe Forte (feldspathic porcelain). The types of linking material between the substructures and veneering material were either fusing or cementation. Observations were compared between aged and non-aged specimens divided into two main groups; (a) non-aged group (b) aged for three years at room temperature. Each group has two subgroups; fused and cemented which are further divided into static and cyclic fatigue at 20K, 60K and 80K. Specimens were subjected to load to failure test using universal test machine. 40% of failure load was calculated for the cyclic fatigue subgroups. In order to examine the difference in failure load between the static and fatigued specimens, the Tukey-Kramer HSD test was used to analyze the data. RESULTS AND CONCLUSIONS: The VITABLOCS Triluxe Forte (feldspathic porcelain) fused to YZ zirconia showed significantly lower failure load values compared to all the other groups (p˂0.05). The non-aged VITABLOCS Triluxe Forte cemented to YZ zirconia (static and cyclic) showed significantly higher load to failure than the aged cemented Triluxe fatigued groups (p˂0.05). There is no significant difference in failure load between IPS e.max CAD fused and IPS e.max CAD cemented to YZ zirconia framework (p˃0.05). The aged IPS e.max CAD fatigued (20K, 60K and 80K cycles) cemented to YZ zirconia showed lower significant difference in failure load among all the other IPS e.max groups. (p˂0.05).

In der vorliegenden Studie wurde an 50 3D-gedruckten Molaren mit einer konstruierten Referenzkaries das Ausmaß der vollständigen Kariesentfernung flächenabhängig überprüft. Die untersuchten Zähne wurden mit einer simulierten, standardisierten und mehrflächigen Karies versehen. Studierende der Zahnmedizin haben die Karies entfernt, die Kavität mit einer Aufbaufüllung versorgt und die Zähne für eine Vollkrone präpariert. Um die Kariesentfernung zu bewerten, wurden DVT-Aufnahmen und dreidimensionale Scans angefertigt. Aus den DVT-Datensätzen im DICOM-Format wurden die Aufbaufüllungen der Zähne mithilfe digitaler Bildverarbeitung segmentiert und als eigenständige 3D-Modelle dargestellt. Anschließend erfolgte die Überlagerung der Aufbaufüllungen auf den Referenzzahn aus der Konstruktionsdatei der Zähne. Mit der Konstruktionssoftware Autodesk Fusion 360 wurden die Aufbaufüllungen in Volumenkörper umgewandelt und mit der Karies des Referenzzahnes verglichen. Da sich die Aufbaufüllungen mit der Referenzkaries überschneiden, konnte die Software mit ihrer Teilungsfunktion nicht überschneidende Teile separieren. Abhängig von der Lage der Kavität, in der sich die überschüssigen Volumenkörper befanden, wurden jene als Restkaries oder überexkavierte Zahnhartsubstanz identifiziert. Die gemessenen Volumina von Restkaries ergaben, dass an der distalen Zahnfläche im Vergleich zur bukkalen und okklusalen signifikant mehr Karies verblieben war. Ein weiterer signifikanter Unterschied konnte zwischen mesial und bukkal, jedoch nicht zwischen mesial und okklusal festgestellt werden. Bei der Überexkavation gab es zwischen den Zahnflächen keine Unterschiede. Die Ergebnisse zeigten, dass die Kariesentfernung an den approximalen Zahnflächen für die Studierenden eine höhere manuelle Herausforderung darstellte. Neben der volumetrischen Vermessung ermöglichte die dreidimensionale Visualisierung von Restkaries und der überexkavierten Zahnhartsubstanz eine objektive Bewertung des Behandlungsergebnisses für die Studierenden und deren Ausbilder. Besonders der Vergleich mit einer Referenz schaffte eine valide und nachvollziehbare Beurteilung der Kariesübung an 3D-gedruckten Zähnen. / In the present study, the extent of complete caries removal was checked on 50 3D-printed molars with a constructed reference caries depending on the tooth surface. The examined teeth were created with a simulated, standardized and multi-surface caries. Dental students removed the caries, filled the cavity with a buildup filling and prepared the teeth for a crown. To assess caries removal, CBCT and three-dimensional scans were taken. From the DVT datasets in DICOM format, the buildup fillings of the teeth were segmented using digital image processing and displayed as 3D models. Then the buildup fillings were matched with the reference tooth from the design file of the teeth. With the Autodesk Fusion 360 design software, the buildup fillings were converted into solids and compared to the caries of the reference tooth. Because the buildup fillings overlap with the reference caries, the software was able to separate non-overlapping parts with its splitting function. Depending on the location of the cavity in which the solids were located, those were identified as residual caries or over-excavated tooth structure. The measured volumes of residual caries showed that significantly more caries was left on the distal tooth surface compared to the buccal and occlusal. Another significant difference was found between mesial and buccal, but not between mesial and occlusal. There were no significant differences in overexcavation between the tooth surfaces. The results showed that caries removal on the approximal tooth surfaces is a higher manual challenge for the students. In addition to volumetric measurement, the three-dimensional visualization of residual caries and over-excavated tooth structure enabled an objective evaluation of the treatment result for the students and their trainers. Especially the comparison with a reference allowed a valid and comprehensible assessment of the caries exercise on 3D-printed teeth.

STATEMENT OF PROBLEM: The production of full arch dental models through Rapid Additive Prototyping (3D Printing) have been questioned for their accuracy in the past decade. PURPOSE: To compare the accuracy of 3D printed and milled dental models, using a digital metrology software. MATERIALS AND METHOD: A mandibular arch typodont was duplicated to produce a conventional Type IV dental stone model. This Model was scanned to create a digital model and an STL file was created which would be sent to Milling and 3D printing machines.15 models were printed using 3 different 3D printing companies and 10 models Milled with a CNC (Computerized Numeric Controlled) milling machine. Each model was scanned and a digital model was created. These scanned models were then super imposed to the scan of the master model through an inspection software (Geomagic Control X, 3D Systems) for accuracy of production. RESULTS: The mean difference in measurement in Absolute Gap, by either of the two methods of prototyping adopted, (0.075 mm for 3D Printed and 0.084 mm for milled) are well below the clinically acceptable values mentioned in previous literature. The means in absolute tooth distance discrepancy for both prototyping methods (0.0361 mm for 3DPand 0.0353 mm for Milled) were not statistically significant. CONCLUSION: 3D printed dental models were more accurate statistically than milled dental models. In general, the mean accuracy for both methods of rapid prototyping is within clinical tolerance and both are clinically acceptable.

71 Studierende nahmen am Universitätsklinikum Würzburg in der Abteilung für Zahnärztliche Prothetik an einem freiwilligen Übungsseminar zum Aufpassen von Kronen mit Störstellen, die im 3D-Druckverfahren hergestellt wurden, teil. Das Übungsseminar fand an zwei Terminen statt. Zum Identifizieren der Störstellen standen Xantopren und Okklusionsspray zur Verfügung. Nach dem praktischen Teil der Übung wurde ein Fragebogen ausgefüllt. Zusätzlich wurden die aufgepassten Kronen mittels Laborscanner digitalisiert und mit einer Krone ohne Störstellen überlagert. Dadurch konnten positive und negative Oberflächenabweichungen für die Bereiche der Störstellen sowie der Gesamtinnenfläche der Kronen ermittelt werden. Die flächenbezogenen Abweichungswerte zeigten einen signifikanten Lernerfolg – gemessen anhand der Passungsparameter - zwischen den beiden Terminen des Übungsseminars. Hierbei erreichten Kronen, die mit Okklusionsspray aufgepasst wurden, signifikant geringere flächenbezogene Abweichungswerte im Vergleich zu Kronen, die mit Xantopren aufgepasst wurden. Die Auswertung der mit Schulnoten skalierten Fragen ergab signifikante Unterschiede bei der Bewertung der Härte, eines realitätsnahen Gefühls beim Einschleifen bzw. beim Aufpassen und Details wie Randschluss. Beim Vergleich der Aufpassmethoden im Fragebogen ergaben die Einfachheit beim Aufpassen, das Identifizieren der Störstellen und das präferierte Material signifikante Unterschiede. Der subjektive Lernerfolg mit den Materialien zeigte ebenfalls signifikante Unterschiede. Insbesondere die Materialeigenschaften und die Randgenauigkeit der Druckkronen wurden häufig kritisiert, die schnelle und einfache Möglichkeit zur Herstellung von Übungsmaterialien sowie deren Reproduzierbarkeit wurden von den Studierenden hingegen begrüßt. / 71 students participated at the Department of Prosthetics of the University of Würzburg in a voluntary training course for fitment optimization of 3D printed crowns with implemented areas of interference. The training course was split into two sessions. Xantopren and a powder spray were utilized to identify interferences. After completing the practical part of the training course students answered a questionnaire. The adapted crowns were digitalized with a laboratory scanner and matched with a crown without interferences. Thus, positive and negative surface deviations were identified for both the areas with interferences and the crowns’ entire inner surface. The comparison of surface deviations between both sessions of the training course revealed a significant learning outcome. Crowns adapted with powder spray had significantly lower surface deviations than crowns adapted with Xantopren. The questionnaire, scaled with school grades, revealed significant differences for evaluation of the crowns’ hardness, realism of the feeling when removing interferences und adaption of the crowns, and details such as marginal fit. When comparing both materials utilized for fitment optimization, the following aspects revealed significant differences: ease for fitment optimization, identification of interferences and preferred material. The subjective learning outcome with both materials revealed significant differences as well. Material properties and accuracy of the crowns’ edges were criticized by the students, however, students appreciated the ease, speed and reproducibility of manufacturing the crowns.

No description available.

No description available.