Engenharia reversa é o conceito de se produzir uma peça tomando como base um original ou modelo físico existentes, sem o uso de desenhos de engenharia. Empresas se voltam para a tecnologia da Engenharia Reversa como um complemento valioso para toda a gama de ferramentas CAD/CAM que elas possuem, devido às dificuldades encontradas quando se necessita trabalhar com superfícies de forma livre. Desta forma, faz-se necessária uma ferramenta que proporcione a inserção das formas deste modelo em um sistema CAD, de forma que se possa usufruir de todas as possibilidades, oferecidas por ele. Neste trabalho, é apresentada uma revisão bibliográfica que aborda a engenharia reversa desde sua origem até as técnicas avançadas existentes atualmente, ou seja, apresentando equipamentos e sistemas específicos usados atualmente para a prática de engenharia reversa. Mostra-se um sistema de engenharia reversa, que foi projetado e implementado realizando a integração desde uma máquina de medir 3 coordenadas até um centro de usinagem CNC com o auxílio de um software CAD comercial, o qual possui módulo de CAM integrado. São apresentados também 3 estudos de casos. / Reverse engineering is the concept of making a part based on an original or existing physical model, without engineering drawings. Companies are using reverse engineering technology as a valuable complement to many of their CAD/CAM tools, due to their difficulties of working with free-form surfaces. It is necessary a tool which provides the insertion of the model forms in the CAD system, therefore enabling to take advantages of all possibilities offered by the system. The Reverse Engineering has developed beyond the traditional copy milling. It is presented a review of the reverse engineering since its origin until recent advanced techniques, where the equipments and specific systems used for reverse engineering practice nowadays are showed. In this work a reverse engineering system has been designed and implemented, which is accomplished by the integration from the coordinate measuring machine until a CNC machining center, by using a commercial CAD software with integrated CAM module. In order to validate the system developed, three case studies are also presented.

Este trabalho descreve uma metodologia para a geração de programas CNC para otimizar um sistema produtivo. Quanto às informações geométricas, o sistema caracteriza-se por utilizar os ciclos de usinagem que o comando da máquina disponibiliza, por possibilitar a aplicação de ciclos desenvolvidos com recursos de programação parametrizada e por gerar novos ciclos, através de uma linguagem genérica, proposta neste trabalho, em um editor de programação parametrizada. Quanto aos dados tecnológicos, ou seja, as condições de usinagem definidas no código de programação, o sistema permite a otimização dos parâmetros de corte através de um banco de dados com informações realimentadas com resultados obtidos da produção. A análise da viabilidade da metodologia proposta é realizada através da implementação de um protótipo de um sistema dedicado à programação de tornos CNC. O protótipo é composto de aplicativos computacionais desenvolvidos e orientados à otimização do sistema produtivo. A metodologia para geração de funções CAD/CAM foi implementada e testada mostrando resultados eficientes. O protótipo implementado como um conjunto de ferramentas aplicativas integradas é de fácil operação e utilização unindo todos os módulos projetados. / This study describes a methodology for the generation of CNC programs to optimize a productive system. Regarding geometrical information, the system is characterized by the use of machining cycles that the machine tool control provides because a allows the application of cycles developed with parameterized programming and by generation of new cycles, through a generic language, proposed in this study on a parameterized programming editor. As for technological data, i.e. the machining conditions set out in the programming code, the system allows the optimization of cutting parameters through a data base with information fed back with results of production. The feasibility analysis of the proposed methodology is accomplished through the implementation of a prototype of a system dedicated to programming CNC lathes. The prototype consists of computer applications developed and oriented to the optimization of the production system. The methodology for the generation of CAD/CAM functions has been implemented and tested showing effective results. The prototype implemented as an integrated set of applicative tools is of easy operation and use connecting all designed modules.

Diploma thesis deals with change of component part production technology. It replaces conventional production technology with CNC machining using CAD/CAM application.

This document describes the design of new production technology specific part in an engineering company. The specific part is manufactured on a machining center by milling method. To create model was used SolidWorks software and to create CNC program was used SolidCAM program. There is production process created with new and old technologies. There is a comparison of both technologies in conclusion.

Magister Scientiae Dentium - MSc(Dent) / CAD/CAM crowns have become popular due to the many advantages associated with this technology. Optimal bonding adhesion is crucial for the durability of these indirect restorations and many factors influence this crucial step. Currently, there is no consensus or evidence-based guidelines on the best adhesion protocol for CAD/CAM crowns fabricated from hybrid materials. This study was aimed at investigating the influence of three types of resin cements on the shear bond strength of a hybrid CAD/CAM material in vitro.

OBJECTIVE: The purpose of this in vitro study was to evaluate the cutting performance and accuracy of CAD/CAM diamond burs in different chemo-mechanical conditions when machining yttria-stabilized zirconia (YTZ), lithium-disilicate, feldspathic porcelain, and double network hybrid ceramic material. The study also examined bur wear mechanisms. MATERIALS AND METHODS: Two experiments were performed. Experiment 1: 45 samples of each material were milled, and four criteria were tested: milling time; surface roughness; change in bur weight after machining, and total cement space. Experiment 2: Four different coolant liquids were used while machining 15 samples of lithium-disilicate, feldspathic porcelain, and double network hybrid ceramic material. The four criteria in Experiment 1, plus marginal adaptation, were measured. Burs and ceramic materials used were examined with SEM before and after machining. RESULTS: Experiment 1: All burs milled 15 crowns of each material successfully, with a general increase in milling time and decrease in weight. Four wear patterns were identified: grit cracks, micro-fractures, dislodgement, and matrix abrasion. Sequential milling time increased for all of the ceramic materials. Surface roughness (Ra) decreased in general for all materials used in the study except YTZ, which showed an increase in Ra by the end of the machining series. Experiment 2: Additives used in this study had no significant effect on IPS e.max CAD milling efficiency or Ra. Boric acid reduced Vita MarkII machining time significantly and Ra. CONCLUSIONS: The cutting rate of diamond burs differed when machining different ceramic materials. In sequential machining, every consecutive milling demonstrated lower cutting efficacy. The surface roughness of consecutive machined samples differed. Some cooling liquids affected the quality of the machined surface. The bur wear mechanism was the same when different ceramic materials were machined, and their microstructure affected their machinability. / 2019-09-26T00:00:00Z

Orientador: Marcos Valério Ribeiro / Resumo: O dissilicato de lítio, Li2Si2O5, é um material vitrocerâmico muito utilizado na fabricação de próteses dentárias, possui grande destaque por ser biocompatível e devido suas propriedades estéticas, químicas e mecânicas, permite a confecção de próteses a partir da usinagem CAD/CAM (COMPUTER-AIDED DESIGN / COMPUTER-AIDED MANUFACTURING), com elevada precisão dimensional e a possibilidade de restauração imediata em pacientes. Os materiais comerciais são disponibilizados com estrutura Li2SiO3 (metassilicato de lítio) cujas características são: alta usinabilidade e baixa tenacidade à fratura. Após a usinagem das próteses, o material sofre tratamento térmico visando à conversão do Li2SiO3 em Li2Si2O5 (dissilicato de litio), fase de melhor tenacidade e excelente apelo estético. A compreensão desta transformação de fase, seus efeitos na usinabilidade e nas propriedades mecânicas é de interesse tecnológico e científico, pois o material será utilizado como prótese dentária após este processamento. Este trabalho visou à avaliação do Li2Si2O5 em relação as propriedades químicas, físicas e mecânicas quando submetido a diferentes tratamentos térmicos. Foram empregados métodos de caracterização por difração de raios X (DRX), microscopia eletrônica de varredura (MEV), massa específica aparente, além da determinação da dureza, tenacidade à fratura, constantes elásticas e resistência à flexão biaxial sob diferentes condições de tratamento térmico. Também foram analisados a distribuição de partí... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-05-23T17:30:49Z No. of bitstreams: 1 DIS_MAURICIO_TOMAZONI_PEIXOTO_COMPLETO.pdf: 977170 bytes, checksum: 550fe78287feca797929ac42cf3a7c9c (MD5) / Made available in DSpace on 2017-05-23T17:30:49Z (GMT). No. of bitstreams: 1 DIS_MAURICIO_TOMAZONI_PEIXOTO_COMPLETO.pdf: 977170 bytes, checksum: 550fe78287feca797929ac42cf3a7c9c (MD5) Previous issue date: 2016-12-13 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The increasing demand for aesthetic restorations, associated with the evolution of techniques and materials, allowed the preparation of prosthetic pieces of reduced thickness. The introduction of CAD / CAM technology has made accurate and fast restorations. However, the final color of the restoration remains the direct responsibility of the dentist, where a visual assessment of color can cause errors, while an instrumental color measurement has accurate readings. The objective of the study was to investigate the factors that may influence the final color and translucency of different veneers with different thicknesses made by CAD/CAM materials and different types of resin cements on a darkened substrate. The samples were made by copy biogeneric in the CEREC SW 4.2 system, after a sample calculation of the pilot project, 60 upper central incisors of the right side of color C3 of epoxy resin were selected in 12 groups of 5 elements, divided according to type of (Lava Ultimate HT and LT), facet thickness (0.3mm / 0.6mm / 1.0mm) and cement type (Relyx Ultimate and Relyx Veneer). After cementation, the samples were taken with the spectrophotometer at a value of ?E in 6 different times with a silicone guide on the tooth, which ensures that the color is uniform. The results showed a significant difference in the values of ?E in groups 1 and 4 (HT and LT of 0.3 mm) cemented with Relyx Ultimate, in groups 7 and 9 (HT of 0.3 mm and 1.0 mm), and in groups 10 And 12 (LT of 0.3mm and 1.0mm) cemented with Relyx Veneer. However, the results were not significant for the masking of the darkened substrate over time, however, significant differences in ?E values were. / A crescente demanda por restaura??es est?ticas, associada a evolu??o das t?cnicas e materiais, possibilitaram a confec??o de pe?as prot?ticas de espessuras reduzidas. A introdu??o da tecnologia CAD/CAM possibilitou a realiza??o de restaura??es precisas e exatas rapidamente. No entanto, a cor final da restaura??o continua sendo responsabilidade direta do dentista, onde uma avalia??o visual de cor pode ocasionar erros, enquanto uma medi??o de cor instrumental possui leituras precisas. O objetivo do estudo foi realizar uma investiga??o dos fatores que podem influenciar a cor final e translucidez de facetas com diferentes espessuras confeccionadas por materiais CAD/CAM e diferentes tipos de cimentos resinosos sobre um substrato escurecido. As amostras foram confeccionadas por c?pia biogen?rica no sistema CEREC SW 4.2, ap?s c?lculo amostral do projeto piloto, foram selecionados 60 incisivos centrais superiores do lado direito de cor C3 de resina ep?xi foram divididos em 12 grupos de 5 elementos, divididos de acordo com tipo de material (Lava Ultimate HT e LT), espessura da faceta (0,3mm/ 0,6mm/ 1,0mm) e tipo de cimento (Relyx Ultimate e Relyx Veneer). Ap?s a cimenta??o, realizou-se a tomada de cor das amostras com o espectrofot?metro pelo valor de ?E em 6 tempos distintos com uma guia de silicone sobre o dente, que garante que a tomada de cor seja uniforme. Os resultados mostraram diferen?a significativa nos valores de ?E nos grupos 1 e 4 (HT e LT de 0,3mm) cimentados com Relyx Ultimate, nos grupos 7 e 9 (HT de 0,3mm e 1,0mm), e nos grupos 10 e 12 (LT de 0,3mm e 1,0mm) cimentados com Relyx Veneer. Entretanto os resultados n?o foram significativos quanto ao mascaramento do substrato escurecido ao longo do tempo, entretanto, foram observadas diferen?as significativas nos valores de ?E ao longo do tempo em uma an?lise intra-grupos.

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-26T14:49:22Z No. of bitstreams: 1 DIS_JONAS_PEREIRA_ANDRADE_PARCIAL.pdf: 141765 bytes, checksum: 99338991681873f9d3d7028d9e7cdfa9 (MD5) / Made available in DSpace on 2017-06-26T14:49:22Z (GMT). No. of bitstreams: 1 DIS_JONAS_PEREIRA_ANDRADE_PARCIAL.pdf: 141765 bytes, checksum: 99338991681873f9d3d7028d9e7cdfa9 (MD5) Previous issue date: 2017-01-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The aim of the study was to evaluate, in vitro, the fracture resistance of occlusal veneers, made by CAD/CAM, with Lava Ultimate, e.max CAD and Vita Enamic materials in thicknesses of 0.6 mm and 1.5 mm. Seventy third human sound molars were randomly divided into seven groups (n = 10) according to the variables material and thickness, with the sound teeth as control. The root of the teeth was embedded into a self-cured acrylic resin and the teeth were prepared to simulate advanced erosion of the occlusal surface. The occlusal veneers were made using CAD-CAM technology, being luted to the preparation with adhesive systems and resin cements. After storage in distilled water at 37 ?C for 24 h, the samples were submitted to mechanical cyclic loading (1 million cycles at 100 N load). Subsequently, the sound teeth and the samples with the occlusal veneers were submitted to the fracture resistance test in a universal testing machine with crosshead speed of 1 mm/min. The failures were classified as reparable and irreparable. According to two-way ANOVA, the interaction between material and thickness was significant (p=0.013). The highest fracture resistance was obtained for the e.max CAD in the thickness of 1.5 mm (4995 N), being statistically superior to the other groups (p <0.05). The lowest fracture resistance was obtained for Vita Enamic at 0.6 mm thickness (2973 N), not being significantly different from e.max CAD 0.6 mm (3067 N), Lava Ultimate 0.6 mm (3384 N), Vita Enamic 1.5 mm (3540 N) and Lava Ultimate 1.5 mm (3584 N) (p>0.05). According to one- way ANOVA, the fracture resistance of the sound teeth (3991 N) did not differ significantly from the teeth with occlusal veneers (p> 0.05). The failures were predominantly repairable, except for sound teeth and Lava Ultimate 1.5 mm. The Lava Ultimate, e.max CAD and Vita Enamic occlusal veneers, in the thicknesses of 0.6 mm and 1.5 mm, showed fracture resistance exceeding the maximum masticatory forces. / O objetivo do estudo foi avaliar, in vitro, a resist?ncia ? fratura de facetas oclusais, confeccionadas por CAD/CAM, com os materiais Lava Ultimate, e.max CAD e Vita Enamic nas espessuras de 0,6 mm e 1,5 mm. Setenta terceiros molares humanos h?gidos foram aleatoriamente divididos em sete grupos (n=10) de acordo com as vari?veis material e espessura, tendo os dentes h?gidos como controle. A raiz dos dentes foi inserida em resina acr?lica quimicamente ativada e os dentes receberam um preparo para simular eros?o avan?ada da superf?cie oclusal. As restaura??es oclusais foram confeccionadas por meio da tecnologia CAD-CAM, sendo cimentadas ao preparo com sistemas adesivos e cimentos resinosos. Ap?s armazenagem em ?gua destilada a 37 ?C por 24 h, as amostras foram submetidas ? ciclagem mec?nica (1 milh?o de ciclos com carga de 100 N). Na sequ?ncia, os dentes h?gidos e as amostras com as facetas oclusais foram submetidas ao ensaio de resist?ncia ? fratura em m?quina de ensaio universal com velocidade de 1 mm/min. As falhas foram classificadas em repar?veis e irrepar?veis. De acordo com ANOVA de duas vias, a intera??o entre material e espessura foi significativa (p=0,013). A maior resist?ncia ? fratura foi obtida para o e.max CAD na espessura de 1,5 mm (4995 N), sendo estatisticamente superior aos demais grupos (p<0,05). A menor resist?ncia ? fratura foi obtida para o Vita Enamic na espessura de 0,6 mm (2973 N), n?o diferindo estatisticamente do e.max CAD 0,6 mm (3067 N), Lava Ultimate 0,6 mm (3384 N), Vita Enamic 1,5 mm (3540 N) e Lava Ultimate 1,5 mm (3584 N) (p>0,05). De acordo com ANOVA de uma via, a resist?ncia ? fratura dos dentes h?gidos (3991 N) n?o diferiu estatisticamente dos dentes com facetas oclusais (p>0,05). As falhas foram predominantemente do tipo repar?vel, com exce??o dos dentes h?gidos e Lava Ultimate 1,5 mm. As facetas oclusais em Lava Ultimate, e.max CAD e Vita Enamic, nas espessuras de 0,6 mm e 1,5 mm, demonstraram resist?ncia ? fratura que excede as for?as mastigat?rias m?ximas.

Kan Yeuk Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Objectives --- p.2 / Chapter 1.3 --- Report Organization --- p.3 / Chapter 2. --- RETROSPECT OF NON-MANIFOLD SOLID MODELING --- p.5 / Chapter 2.1 --- Geometric Modeling --- p.5 / Chapter 2.2 --- Euclidean Space and Topological Space --- p.6 / Chapter 2.3 --- Domains of Solid and Non-Manifold Geometric Modeling --- p.8 / Chapter 2.3.1 --- r-set Domain --- p.8 / Chapter 2.3.2 --- Manifold Domain --- p.9 / Chapter 2.3.3 --- Adjacency Form of Topology --- p.11 / Chapter 2.3.4 --- Cell Complex --- p.13 / Chapter 2.4 --- Representation Schemes of Solid and Non-Manifold Geometric Modeling --- p.14 / Chapter 2.4.1 --- Spatial Decomposition --- p.14 / Chapter 2.4.2 --- Constructive Solid Geometry (CSG) --- p.15 / Chapter 2.4.3 --- Boundary Representations (B-rep) --- p.17 / Chapter 2.5 --- Summary --- p.20 / Chapter 3. --- BOOSTING UP THE SPEED OF BOOLEAN OPERATIONS --- p.21 / Chapter 3.1 --- Solid Modeling with Specialized Hardware --- p.22 / Chapter 3.1.1 --- Modeling with a 4x4 Determinant Processor --- p.22 / Chapter 3.1.2 --- Ray Casting Engine --- p.24 / Chapter 3.2 --- Solid Modeling with General Purposed Parallel Computer --- p.25 / Chapter 3.2.1 --- Modeling with Shared Memory Parallel Computer --- p.27 / Chapter 3.2.2 --- Modeling with SIMD Massively Parallel Computer --- p.27 / Chapter 3.2.3 --- Modeling with MIMD Distributed Memory Parallel Computer --- p.30 / Chapter 3.3 --- Summary --- p.33 / Chapter 4. --- OVERVIEW OF DECmpp 12000/Sx/8K --- p.34 / Chapter 4.1 --- System Architecture --- p.34 / Chapter 4.1.1 --- DECmpp Sx Front End --- p.34 / Chapter 4.1.2 --- DECmpp Sx Data Parallel Unit --- p.35 / Chapter 4.1.2.1 --- Array Control Unit --- p.35 / Chapter 4.1.2.2 --- Processor Element Array --- p.35 / Chapter 4.1.2.3 --- Processor Element Communication Mechanism --- p.36 / Chapter 4.2 --- DECmpp Sx Programming Language --- p.37 / Chapter 4.2.1 --- Variable Declarations --- p.37 / Chapter 4.2.2 --- Plural Pointers --- p.38 / Chapter 4.2.3 --- Processor Selection by Conditional Expressions --- p.39 / Chapter 4.2.4 --- Processor Element Communications --- p.39 / Chapter 4.3 --- Summary --- p.40 / Chapter 5. --- ARCHITECTURE OF THE NON-MANIFOLD GEOMETRIC MODELER --- p.41 / Chapter 6. --- SEQUENTIAL MODELER --- p.43 / Chapter 6.1 --- Sequential Half-Wedge structures (SHW) --- p.43 / Chapter 6.2 --- Incremental Topological Operators --- p.51 / Chapter 6.3 --- Sequential Boolean Operations --- p.58 / Chapter 6.3.1 --- Complementing the subtracted model --- p.59 / Chapter 6.3.2 --- Computing intersection of geometric entities --- p.59 / Chapter 6.3.3 --- Construction of sub-faces --- p.53 / Chapter 6.3.4 --- Extraction of resultant topological entities --- p.64 / Chapter 6.4 --- Summary --- p.67 / Chapter 7. --- PARALLEL MODELER --- p.68 / Chapter 7.1 --- Parallel Half-Wedge Structure (PHW) --- p.68 / Chapter 7.1.1 --- Pmodel structure --- p.69 / Chapter 7.1.1.1 --- Phwedge structure --- p.69 / Chapter 7.1.1.2 --- Psurface structure --- p.71 / Chapter 7.1.1.3 --- Pedge structure --- p.72 / Chapter 7.1.2 --- Pmav structure --- p.73 / Chapter 7.2 --- Parallel Boolean Operations --- p.74 / Chapter 7.2.1 --- Complementing the subtracted model --- p.75 / Chapter 7.2.2 --- Intersection computation --- p.79 / Chapter 7.2.2.1 --- Distributing geometric entities --- p.80 / Chapter 7.2.2.2 --- Vertex-Vertex intersection --- p.89 / Chapter 7.2.2.3 --- Vertex-Edge intersection --- p.89 / Chapter 7.2.2.4 --- Edge-Edge intersection --- p.89 / Chapter 7.2.2.5 --- Vertex-Face intersection --- p.90 / Chapter 7.2.2.6 --- Edge-Face intersection --- p.92 / Chapter 7.2.2.7 --- Face-Face intersection --- p.93 / Chapter 7.2.3 --- Constructing sub-faces --- p.98 / Chapter 7.2.4 --- Extraction and construction of resultant topological entities --- p.100 / Chapter 7.3 --- Summary --- p.106 / Chapter 8. --- THE PERFORMANCE OF PARALLEL HALF-WEDGE MODELER --- p.108 / Chapter 8.1 --- The performance of converting sequential to parallel structure --- p.111 / Chapter 8.2 --- The overall performance of parallel Boolean operations --- p.112 / Chapter 8.3 --- The percentage of execution time for individual stages of parallel Boolean operations --- p.119 / Chapter 8.4 --- The effect of inbalance loading to the performance of parallel Boolean operations --- p.121 / Chapter 8.5 --- Summary --- p.125 / Chapter 9. --- CONCLUSIONS AND SUGGESTIONS FOR FURTHER WORK --- p.126 / Chapter 9.1 --- Conclusions --- p.126 / Chapter 9.2 --- Suggestions for further work --- p.127 / APPENDIX / Chapter A. --- SEQUENTIAL HALF-WEDGE STRUCTURE --- p.A-1 / Chapter B. --- COMPUTATION SCHEME IN CHECKING A FACE LOCATING INSIDE THE FACES OF A SOLID --- p.A-3 / Chapter C. --- ALGORITHM IN FINDING A HALF-WEDGE WITH A DIRECTION CLOSEST FROM A REFERENCE HALF-WEDGE --- p.A-5 / Chapter D. --- PARALLEL HALF-WEDGE STRUCTURE --- p.A-7 / REFERENCES --- p.A-10