L'assemblage de planches par technique de collage est utilisé pour réaliser des éléments de structure en bois performants. Le collage permet d'obtenir des rigidités et des résistances d'assemblages excellentes. Cependant, ces produits sont souvent polluants à différents degrés et ne permettent pas de s'adapter à une cadence industrielle de fabrication, notamment à cause des temps de pressage. Le niveau de performance s'effondre lorsque l'assemblage par collage est remplacé par des organes de type tige, tels que des pointes, vis ou tourillons en bois, mais ils confèrent un temps de mise en oeuvre instantané. Dans ces types d'assemblages mécaniques, la surface de contact entre les planches n'est plus du tout utilisée pour transmettre des efforts. L'objectif de ce travail est de montrer comment la préparation mécanique des interfaces permet de fortement améliorer le comportement de ces assemblages. La finalité étant de produire des éléments de structure sans composés organiques volatiles (COV), dont la fabrication serait réalisable par un robot industriel, de manière flexible et en utilisant des essences mixtes de bois locaux. La première partie de cette étude est consacrée à répertorier et analyser les différents systèmes reconstitués en bois, ainsi que de montrer comment mener un dimensionnement en tenant compte du caractère imparfait de la connexion. Cette partie montre que la prise en compte du caractère non linéaire des liaisons mécaniques dans les systèmes reconstitués est souvent très imprécise et conduit à des écarts de dimensionnement importants. La deuxième partie décrit une méthodologie pour pallier à ce manque, développée à partir de la modélisation non linéaire d'un élément de construction de type poutre. Cette approche conduit à proposer des raideurs sécantes précises de la liaison permettant le calcul linéaire exact pour les ingénieurs. Cette méthodologie permet de caractériser la raideur d'une liaison par une approche liée au comportement plutôt qu'une approche normative générale. Suite à la mise en évidence de la souplesse de la liaison par organes, une troisième partie expose une réflexion sur l'utilisation des surfaces en contact pour transmettre les efforts. Un traitement mécanique de type rainurage est réalisé à l'interface de contact des pièces à assembler. Il permet de transmettre des efforts de cisaillement et de torsion dans le plan de croisement des planches. Le maintien des éléments en contact est également étudié en développant un principe de vis conique en bois. Pour valider ces principes, des campagnes d'essais sont réalisées afin de mesurer les performances obtenues par le rainurage, la vis conique en bois et leurs utilisations simultanées. La dernière partie est consacrée à la mise en oeuvre de l'assemblage amélioré dans des éléments de structure afin d'en confirmer son potentiel. Le premier élément est une poutre ajourée, le second est un élément de mur contreventant. Les résultats d'essais sont comparés à des modèles numériques incluant le comportement non linéaire des assemblages rainurés vissés. Ces réalisations en grandeurs réelles permettent de valider également leur faisabilité par un robot industriel / Plank bonding connection is used to produce efficient structural timber. The bonding achieves excellent rigidity and connection resistance. However, these products are often pollutants and are incompatible with industrial production rates due to the pressing time. Their performances collapse when the adhesive connection is replaced by rodlike fasteners, such as nails, screws or wooden dowels, but these connections allow a quick assembly. In these assemblies the contact surfaces between planks are not used for transmitting loads. The purpose of this study is to point out how mechanical preparation of the interfaces improves the performance of timber connections. The aim is to produce structural members without volatile organic compounds (VOC), achievable by an industrial robot allowing for flexibility, and using mixed wood local species. The first part of this study consists in identifying and analyzing reconstituted wood systems, as well as showing how to conduct a design by taking into account the partial composite action of connectors. This part explains that the chosen behavior of the mechanical connections in reconstituted systems is frequently very imprecise and leads to significant differences in design. The second part describes a methodology to overcome this lack, developed from the nonlinear modeling of a beamtype component. This approach leads to determine the fastener's secant stiffness for an exact linear calculation for engineers. The outcome of this methodology is the quantification of the fastener's secant stiffness by a related behavior rather than a general normative behavior. Due to the flexibility of members, a third part presents a reflection on the use of the contact surfaces for transmitting loads. The plank interfaces were machined in order to obtain grooves. This binding allows the transmission of shear and torsion forces in the intersection plane of the planks. Maintaining the contact is managed by the development of a wooden conical screw. To validate these principles, test campaigns were carried out to measure the performance of the groove, the wooden conical screw and their simultaneous use. The last section deals with the implementation of the improved assembly in structural members in order to confirm its potential. The first element type is a castellated beams and the second one is a bracing wall. Experimental results are compared with numerical models including the nonlinear grooved screwed connection behavior. Furthermore, these full scale elements validate the feasibility by an industrial robot

Orientador: Amauri Hassui / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-26T13:19:17Z (GMT). No. of bitstreams: 1 Menezes_LucianodeJesus_M.pdf: 3153404 bytes, checksum: 2d45745d89221fa761d7b0111aaf819a (MD5) Previous issue date: 2014 / Resumo: A evolução dos sistemas CAD/CAM, das máquinas-ferramenta CNC e das geometrias e materiais das ferramentas de corte tem tornado possível desenvolver processos de fabricação de moldes e matrizes mais eficazes. Normalmente, a quantidade de horas necessárias para a usinagem dos componentes dessas ferramentas é elevada e, mesmo assim, muitos dos perfis complexos não são possíveis de serem usinados por completo em centro de usinagem 3 eixos, necessitando a utilização de outras máquinas e processos, como a eletro-erosão (EDM), retificadoras e polimento manual. A utilização do fresamento com máquinas de usinagem 5 eixos tem sido um dos caminhos para a usinagem dos componentes complexos de moldes e matrizes, de modo a minimizar o uso de máquinas e processos adicionais. Com a finalidade de contribuir para melhorar a eficiência da fabricação de moldes e matrizes, este trabalho tem como objetivo estudar as condições dimensionais e as forças geradas no fresamento do Aço AISI D6 endurecido a 58HRC, usinado em um centro de usinagem 5 eixos com fresa de topo esférica. A condição dimensional estudada está relacionada com o perfil geométrico do corpo de prova, composto por raio e superfície plana. O estudo foi realizado utilizando 10 estratégias de usinagem, variando-se o ponto de contato da ferramenta com o corpo de prova, o sentido de usinagem e a velocidade de corte. As análises práticas realizadas mostraram que existe relação entre a tolerância geométrica, o desgaste da ferramenta e as estratégias de corte adotadas. Além disso, as condições, máquinas e equipamentos utilizados nos ensaios de usinagens descendentes 3 eixos obtiveram melhores resultados de tempo de vida da ferramenta e condição dimensional do corpo de prova / Abstract: The development of CAD / CAM systems, CNC machine tools and materials and geometries of cutting tools has become possible to develop more efficient manufacturing processes of molds and dies. Usually the amount of hours required for machining of the components of these tools is high. Also, many of the complex profiles are not possible to be completely machined in 3-axis machine center, requiring the use of other machines and processes, such as electro-erosion (EDM), grinding and hand polishing. The use of milling machines with 5-axis machining has been one of the paths for machining complex components from molds and dies, so as to minimize the use of additional machines and processes. In order to contribute to improve the efficiency of manufacturing molds and dies, this work aims to study the dimensional requirements and the forces generated when milling Steel AISI D6 hardened to 58HRC, machined in a machining center with 5-axis milling spherical top. The dimensional condition studied is related to the geometric profile of the specimen, consisting of ray and flat surface. The study was conducted using 10 machining strategies, varying the tool point of contact with the specimen, the machining direction and the cutting speed. The practical analyzes showed that there is a relationship between the geometric tolerance, tool wear and cutting strategies adopted. In addition, the conditions, machinery and equipment used in the machining tests descendants 3 axes obtained better lifetime results tool and dimensional condition of the specimen / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

During the past three years, a research project has been carried out in the Department of Mechanical Engineering at UCT, directed at developing a system to accurately reproduce three-dimensional (3D), sculptured surfaces on a three axis computer numerically controlled (CNC) milling machine. Sculptured surfaces are surfaces that cannot easily be represented mathematically. The project was divided into two parts: the development of an automatic noncontact 3D measuring system, and the development of a milling system capable of machining 30 sculptured surfaces (Back, 1988). The immediate need for such a system exists for the manufacture of medical prostheses. The writer undertook to investigate the measurement system, .with the objective to develop a non-contact measuring system that can be used to 'map' a sculptured surface so that it can be represented by a set of XYZ coordinates in the form required by the milling system developed by Back (1988). This thesis describes the development of a PC-based near-realtime photogrammetry system (PHOENICS) for surf ace capture. The topic is introduced by describing photogrammetric principles as used for non-contact measurements of objects. A number of different algorithms for image target detection, centering and matching is investigated. The approach to image matching adopted was the projection of a regular grid onto the surface with subsequent matching of conjugate grid intersections. A general algorithm which automatically detects crosses on a line and finds their accurate centres was developed. This algorithm was then extended from finding the crosses on a line, to finding all the intersection points of a grid. The algorithms were programmed in TRUE BASIC and specifically adapted for use with PHOENICS as an object point matching tool. The non-contact surface measuring technique which was developed was used in conjunction with the milling system developed by Back (1988) to replicate a test object. This test proved that the combined system is suitable for the manufacture of sculptured surf aces. The accuracy requirements for the manufacture of medical prostheses can be achieved with the combined measuring and milling system. At an object-to-camera distance of 0.5 m, points on a surface can be measured with an accuracy of approximately 0.3 mm at an interval of 5 mm. This corresponds to a relative accuracy of 1:1600. Back (1988) reported an average undercutting error of 0.46 mm for the milling system. This combines to an uncertainty of 0.55 mm. Finally, the limitations of PHOENICS at its prototype stage as a surface measuring tool are discussed, in particular the factors influencing the system's accuracy. PHOENICS is an ongoing project and the thesis is concluded by some recommendations for further research work.

The aim of this paper is to provide an overview of the available strategies for milling of closed pockets. In particular, it focuses on advanced programming using CAM programs. In the next parts, the work is focused on the analysis of the force load of tools in the machining of the pockets. Here it focuses on the course of forces in milling at the corner of the pocket using different methods of analyzing this load. There are also ways to reduce this burden.

Diploma thesis deals with the design of a small, computer-controlled machine tool. It is used for gearwheels production and combines the two most used manufacturing methods. The dissertation was dealt with in cooperation with a business subject which focuses on the development of milling machines. The introductory section is discussing research of current state of knowledge and market research focused on gearing machine tools, including patent investigation. The conceptual solution is discussing several variants of the cinematographic arrangement of the axes from which the final design solution was developed. This is described in detail in the second part of the dissertation. It contains description of individual construction complexes, choice of propellant units, modal analysis of sliding systems using the method of finite elements and in the conclusion the electronic part of the machine with its overall shape solution.

This diploma thesis deals with the proposal and production of a mold for series production of plastic parts by vacuum forming. The thesis is divided into 2 main chapters. The theoretical part includes analysis of chip machining technology. The experimental part focuses on solving the design of the mold in PowerShape software, a detailed analysis of making of the model for casting and about making of the mold themselves. In the last part the manual completion and verification of the mold is discussed. Thesis is terminated by technical-economic evaluation, in which is discussed about production costs.

Dry bean utilization by the food industry can be increased by developing value-added processing applications. The goals of this research were to evaluate (1) the effect of milling method on the physical, chemical and functional properties of whole black bean flour and its fractions and (2) the effect of removing soluble phenolic compounds on the functional and rheological properties of black bean protein isolates. Black bean was milled with five laboratory mills [cyclone mill, hammer mill, stone mill (fine, medium, coarse), disc mill (fine, coarse), and centrifugal mill (10,000 or 12,000 rpm and 250, 500, 1000 μm aperture screen)] and the resulting flours were evaluated for their physical, chemical and flow properties of bulk samples and particle size fractions. Whole black bean flour and cotyledon flour were subjected to phenolic extraction and protein isolation, resulting in protein isolates with and without soluble phenolics. Solubility, wettability, dispersibility, water binding capacity, foam capacity and stability, emulsification capacity, and gelation properties of protein isolates were evaluated. Variation in milling method produced flours with significantly different flour characteristics. Geometric mean size of whole bean flour was negatively correlated with starch damage (r = -0.92), L* (r = -0.94), angle of repose (r = -0.94), and angle of slide (r = -0.80 to -0.90) and positively correlated with moisture (r = 0.72), and loose bulk density (r = 0.72). Milling method and particle size interaction was significant on characteristics of black bean flour fractions. Particle circularity of flour fractions had a negative correlation of r = -0.93, r = -0.81, r ≈ -0.95, and r = -0.94 with L*, angle of repose, angle of slide and compact density, respectively. Particle circularity had a positive correlation of r = 0.93 and r = 0.89 with average minimum particle size and loose bulk density, respectively. The removal of soluble phenolic compounds improved the brightness, solubility, wettability, dispersibility, foaming capacity, foaming stability, emulsion capacity, emulsion stability and gelling properties of protein isolates. These findings will help food manufacturers to process black bean ingredients using different mill settings to achieve different functionalities depending on the consumer requirements.

Two sets of durum samples were used to determine kernel characteristics and milling properties of durum genotypes grown in North Dakota, USA. Kernels were characterized for kernel size (length, width, and thickness), germ size (length and width), and shape (kernel width/kernel length, volume, sphericity, germ width/germ length, germ length/kernel length, and germ width/kernel width). Kernels were also characterized for their test weight, kernel weight, vitreousness and hardness. Milling properties evaluated were break release, milling rate, total extraction, semolina extraction, and semolina quality. All kernel characteristics and milling properties varied with genotype and growing location. First break release and milling rate were influenced by kernel shape and size. Larger, wider, and rounder kernels tended to result in better milling performance in the first break. Kernel hardness and vitreousness were strongly correlated and both were positively correlated to semolina extraction but not total extraction.

This dissertation treats of the influence of PVD coats to a change of tool lifetime. The theoretical part of the dissertation describes the adjustment of tools before the process of coating. Following part describes the specific properties of deposited layers of the coating and its measuring. There is also the enumeration and specification of selected ways of depositing PVD coats and brief description of its advantages and disadvantages. Second part of the dissertation is focused on an experiment with measuring of the tool force loading and its change depending to the tool wear. There are compared four short four-edged milling cutters with a coat and as well without it. Those tools were made of high speed steel by the conventional way and also by the powder metallurgy. Milling operation was done by down and up milling technique. The evaluation of the experimental results for powder metallurgy tools confirmed that these tools are advantageous compared to the standard high speed steel tools.

roject own model of workpiece. Choose competent machine tools for machining. Strategy analysis of machining in software PowerMILL. NC programs processing for given application. Experimental verification of NC programs with system Sinumerik 840D.