Estudo do fresamento de madeiras em centro de usinagem CNC

The lack of research related to wood machining processes, including the milling, as well as the increased use of this material in the industrial sector, it creates a need to increase research involving these processes, as the sector is in full technological and environmental remodeling. This paper studies the process of milling wood, presenting an analysis of the effects of cutting speed on surface quality by measuring roughness. We used a forward speed three cutting speeds, two species of wood (Pinus elliottii and Eucalyptus grandis) and two milling tools (roughing and finishing) machined by milling concordant and discordant. Each condition was repeated six times, and the measurements were performed in the opposite direction and in favor of cutting tool, generating results of the parameters Ra (average roughness) totaling 144 trials with it. These results were statistically analyzed using analysis of variance and Tukey test. Finally it was concluded that there are significant differences between the results of varying roughness when cutting speeds, milling and types of machining types tested

Aplicações da ilustração científica em ciências biológicas

A Ilustração Científica é um trabalho que consiste na representação fiel de um material biológico determinado, respeitando-se todas as medidas, proporções e contraste de cores, mesmo que em preto e branco. Por isso, a capacidade de observação é uma qualidade indispensável para que se tenha um bom resultado. Podem ser desenhos de materiais vivos, extintos, arqueológicos e até processos cirúrgicos e devem ser claro em significado, não poluído e que não provoque nenhum tipo de incompreensão ou dúvidas. Ela é altamente utilizada no meio acadêmico tendo um vasto campo de aplicação, variando desde trabalhos mais simples e esquemáticos aos mais complexos com alto nível de acabamento e detalhamento. Independentemente à técnica, as ilustrações científicas ainda são uma ferramenta de extrema importância e de grande utilização, sendo muito solicitadas por pesquisadores, que desejam enriquecer seus trabalhos, torná-los mais explicativos, mais claros, e mais didáticos. Por mais que se tenha a possibilidade das fotografias modernas, um desenho empregando técnicas tradicionais como acabamento é totalmente indispensável, já que a foto, por mais sofisticada e cheia de recursos que possua a máquina, não consegue transmitir todos os detalhes e estruturas que se deseja em uma mesma fotografia. O artista tem a liberdade de montar uma prancha com aquilo que o pesquisador precisa, usando sua percepção visual e destreza para reproduzir com exatidão o material em questão. Recursos digitais, ao contrário do que muitos acreditam, não tiraram o espaço das técnicas tradicionais, mas veio como mais uma opção de ferramenta de trabalho que, aliás, para usá-la é necessário saber desenhar igualmente àquele que não se utiliza desse recurso. O tempo passou, as sociedades mudaram e as representações...(Resumo completo, clicar acesso eletrônico abaixo)

Fresamento de madeiras de média densidade: MDF

The technological expansion and market manufactured wood as wood paneling makes the research of processes involving this material are increasingly necessary . The present study examines the milling process MDF - fiberboard with average density endmill with helical teeth , with the analysis of the surface finish by evaluating the surface roughness ( Ra) and analysis of the power consumption . We analyzed three types of cuts in milling : concordant , discordant , and cut top . We used 5 rpm (6000 , 8000 , 10000 , 12000 and 14000 RPM) , establishing five-speed cutting, 301 , 402 ,502, 603 and 703 m / min respectively. Five forward speeds and 4, 6, 8, 10 and 12 m / min. Each condition was repeated six times , totaling 180 tests. The results of roughness were obtained from rugosimeter data and the power consumption were obtained by Hall-effect sensor . These results were statistically analyzed using analysis of variance and Tukey test . Finally it was concluded that there are few significant differences between the results themselves vary roughness when cutting speeds and feed and no major differences in power consumption . The best surface quality and lower power consumption were for cutting speed of 703 m / min . To varying forward speed , the speed of 4 m / min showed better surface quality and lower power consumption

Fresamento de Eucalyptus grandis

The process of milling wood is widely used in operations such as planing and manufacturing frames . Machines like planers , desengrossadeiras , routers , moldureiras and machining centers employ the milling process for cutting wood . In this work the process of milling CNC machining center of Eucalyptus grandis was studied because this is very much used in furniture , but without consistent studies on this process . This work a CNC machining center brand TECH Z1 for analysis of surface quality ( Ra ) in relation to the variation of cutting speed and feed in concordant and discordant tangential milling and face milling was used . We used Eucalyptus grandis . Four forward speeds ( 3, 5 , 7, and 9 m / min ) for four shear rates ( 5,9; 8,4; 10,9 and 13,4 m/s ) were used. Was used for testing a cutter finishing top speed steel with helical teeth 16mm in diameter . 6 repetitions for each test condition were performed . From the results it was observed that the best results for roughness Vc = 10,9 m / s were obtained for the milling concordant with the forward speed Vf = 7 m / min. As for Vf = 5 m / min the best finish was achieved with Vc = 8,4 m /s in discordant for milling . The feedrate and cutting influenced the roughness . The senses of concordant and discordant and cut the top and the top had a significant difference in roughness

Influência da aplicação de cargas estáticas axias e não axais em próteses parciais fixas de três elementos, análise pela extensometria

Um bloco de poliuretano recebeu três implantes de hexagono externo, no posicionamento compensado. Para cada implante foi conectado o pilar protético microunit. Foram realizados cinco enceramentos com três coifas plásticas cada um, que foram fundidos em monobloco numa liga de cobalto-cromo. Foram colados quatro extensomêtros tangenciando cada implante, sendo dois extensomêtros para o implante central. Após o acabamento, as estruturas foram fixadas nos respectivos locais com o parafuso de retenção com torque de 10 Ncm, obtidos com um torquímetro. Para aplicação de carga sobre os corpos-de-prova foram selecionados cinco pontos de aplicação de carga. O dispositivo de aplicação de carga–DAC foi utilizado 30 kg de cargas verticais estáticas, empregando uma ponta esférica de 2 mm de diamêtro, durante 10 segundos em cada um dos pontos estabelecidos, sendo, neste instante registradas as micro deformações de cada extensômetro. Foi utilizado o teste de análise de variância T Student e o nível de significância foi o valor convencional de 5%. Para cada implante foi analisada a microdeformação ocorrida. Os resultados obtidos mostraram que houve uma diferença estatisticamente significativa entre os pontos não-axiais D e E (t = 5,21 df = 4, p = 0,006 < 0,05) e não foi estatisticamente significativa para os dados axial entre os pontos B e C (t = 6, 57, df = 4, p = 0,003 < 0,05 / 3). Conclui-se que,a aplicação de carga ao redor de três implantes de hexágono externo no posicionamento compensado,mostra que os pontos não-axiais sofrem maior micro deformação do que os pontos axiais

Desenvolvimento de um protetor lateral em alumínio

In view of the need to develop a device for security and lateral protection, due to the Resolution 323/09 of CONTRAN, which requires the use of such equipment for most trucks and tow trucks, the objective of this work is to develop a project for an aluminum lateral protection device, according to the ABNT NBR 14.148 regulation, that, among many specifications, stipulates that the equipment must support a load of 5 kN and suffer a maximum deflection of 30mm, but does not say what material it should be made of. The reason for choosing aluminum is because of its low density, so as not to significantly increase the curb weight of the truck, which, consequently, reduces CO2 emissions and maintenance expenses. Additionally, this material presents a good resistance/weight ratio, high resistance to corrosion, excellent surface finish and it's fully recyclable; reason why it has been gaining the attention of many industry segments. For the realization of the project, profiles were chosen to make the assembly of the set, and then a finite elements analysis was performed in the HyperWorks software, to verify if the designed device would support the loads stipulated by the regulation. One details to note is that these simulation programs could show inaccuracies, because of the size and shape of the elements that compose the mesh, and for many other reasons, so it is necessary that, even with the results coming back satisfactory, actual physical tests are conducted to validate the proper functioning of the equipment, which was not done for this study

Carne Bovina: Produtividade Vs Qualidade

Bovine meat exerts an important contribution to the human diet, mainly by its high biological value. For this reason the productivity and the quality of beef are so discussed. Productivity is defined as the ratio between production and the factors of production used and quality defined as an adjective given to the product that suits the consumer implicit and explicit. Brazil is the world leader in tonnage exported bovine meat, however the country has a relatively low income, since no exports to the markets of greater added value. Quantify the degree of importance of these two factors in a capitalist market is not easy, so knowing the science that involves this product is vital for both factors. We must know that there is a wide variability in the markets importers and Brazil should seek to be the leader everywhere, whether carcass with better conformation and degree of finish, is lean beef, organic meat is even

Lixamento do Pinus elliotti com carbeto de silício e óxido de aluminio

The Sanding is a complex process involving many variables that affect the quality of the part produced, working mainly in the timber industry in the production of panels (MDF, MDP, HDF, etc...) and furniture. However, these industries use the sanding process empirically, not optimizing it. The aim of this study was to compare the behavior of sandpaper white aluminum oxide (OA-white) and Black silicon carbide (SiC-black), analyzing variables in the process as: strength, power, emission, vibration, wear particle size of sanding, and its consequences on the surface finish of the workpiece. Made the process of plane grinding samples of Pinus elliottii, processed in parallel to the fibers, which were sanded with sandpaper grain OA white and black 3-SiC abrasive conditions (new, moderately eroded and severely eroded) grain sizes in 3 (80, 100, and 120 mesh). 6 replicates was performed for each condition tested. Each trial was captured output variables of the sanding process: strength, power, emission and vibration. With two stages totaling 108 trials. After the sanded samples, it has the same surface quality by raising the surface roughness Ra. Through experiment, it can be concluded that abrasives OA-white tended to have higher strength, power, emissions and less vibration in the sanding process, compared to the SiC-black. However, surface finish exhibited similar to the particle size of 80 to 100 mesh, worn abrasive conditions. However, the particle size of 120 mesh, obtained by the roughness of sandpaper OA-bank was higher compared to SiC-black to all conditions of sandpaper due to its toughness

Comparação de compósitos obtidos via RTM de resina epóxi e fibra de carbono com e sem descontinuidade nos tecidos

Technology is growing interest in the use of composites, due to the requirement of lighter materials and more resistant, factors essential to meet the project specifications and reduce the operational cost. In the production of high performance structural composites, considering the aerospace criteria, the domestic industry has shown interest in the process of resin transfer molding (RTM) for reproducibility and low cost. This process is suitable for producing components of polymeric composites with relatively simple geometries, consistent thicknesses, high quality finish with no size limitations. The objective of this work was machined carbon steel to make a matched-die tooling for RTM and produce two composite plates of epoxy resin and carbon fiber fabric with and without induced discontinuities, which were compared towards their impregnation with ultrasound, their properties via tensile tests and thermal analysis. In ultrasonic inspection, it was found good impregnation of the preform of both composites. In the thermal analysis it was possible to check the degradation temperature of the composites, the glass transition temperature and it was found that the composites showed no effective cure cycles, but presented good performance in the tensile test when compared with aluminum alloy 7050 T7451 . The results showed that the injection strategy was appropriate since the laminate exhibited a good quality for the proposed application

Efeito da variação da velocidade de corte e de avanço no torneamento de Eucalipto

Due to the rapid development of some species such as pine and eucalyptus and a growing demand for raw materials, timber, there was a need for detailed studies to better use and higher quality in products derived from wood. In order to contribute to to better utilization of wood ,this study aims to analyze the quality of the wood surface after machining Corymbia citrodora around, with varying feed rates (40, 70, 100 mm/mim), shear rate (1.88, 2.19, 2.51 m/s) and with the use of inserts for turning new and used (cemented carbide). 18 were used bodies and each body was made three different assays for each test were a total of 54 tests three replicates. This study will also addres the analysis of power consumption for each of the tests. With the results obtained through experiments, including the surface roughness of parts and power consumption for each test, we try to evaluate the power consumption in machining with the variations in cutting speed and feed, with two tools carbide

Obtenção e caracterização de compósitos via RTM com alta fração de fibras de carbono processados à temperatura ambiente

After confirming the high specific mechanical properties of composite materials by scientific studies conducted over the last decades, one of the challenges of this new class of materials is the ability to achieve mass production at a more affordable cost, which has become indispensable. The Resin Transfer Molding (RTM) is an excellent method for manufacturing composite materials. Despite being a process widely used by international companies in the production of high performance structural composites, only a short time the national aviation industry has shown interest in implementing this type of processing to more complex structures and greater structural responsibility. In aeronautical projects, the reproducibility and the relative low cost of this process, several studies have been performed in Brazil for learning and perfecting this technique. This process is suitable for producing polymer components both simple as complex geometry, and allows to achieve consistent thickness, with high quality finish and without limiting range. Polymeric composite components for the high mechanical stress applications such as aircraft structures, satellites, etc., require a strict control of volume fractions of the composite constituents, beyond the knowledge of their mechanical and thermal properties. Therefore, in this experimental work degree study on the mechanical, thermal and of porosity composites processed by RTM processed characterization was performed. This characterization was performed targeting a possible aerospace application of this composite material. For the production of composites, process equipment (RTM RTM injector Radius 2100cc) was used. The processed carbono/epoxy composites were characterized via flexure tests mechanically and thermally analysis via DMA, DSC and TGA. To determine the volume fraction of fibers, the composite samples were analyzed via matrix digestion (ASTM D3171) ... (Complete abstract click electronic access below)

Estudo da influência da aplicação do fluido de corte no torneamento da liga de alumínio AA7075

One of the ways to minimize the effects of unproductive time caused by tool wear can be achieved by introducing an efficient system of lubrication and cooling in the process. However, in the last decade the research had the goal to restrict the maximum use of refrigerants and / or lubricants in metal-mechanical production. The important factors that justify this procedure include the operational costs of production, ecological issues, and the legal requirements of environmental conservation and preservation of human health. The purpose of the proposed work is the study of machining by turning with the focus on the influence caused by the application of cutting fluid in several ways of application (abundant and MQF) and also by comparing the results obtained by machining without the presence of fluid . For this purpose, the turning tests are conducted using an aluminum alloy (AA 7075). The response variables to be analyzed were obtained from the roughness (Ra and Ry), the stresses presented (VB) and their progression in relation to the cutting length achieved, the type of chip formed, in addition to changes in the degree of finish (roughness) presented by the turned parts. The results of this study should provide more detailed information about the actual influence of cutting fluids in turning this alloy, which are characterized by high rates of deformation when the formation of damaging your chip machining and also the quality of surface generated. Therefore, it is expected to provide subsidies to promote the optimization of machining this alloy making the most of the role of cutting fluid

Estudo em fadiga no aço API 5L X80 soldado pelo processo HF/ERW

The technological advancement in order to improve the methods of obtaining energy sources such as oil and natural gas is mainly motivated by the recent discovery of oil reserves. So, increasingly , there is a need for a thorough knowledge of the materials used in the manufacture of pipelines for transportation and exploration of oil and natural gas. The steels which follow the API standard (American Petroleum Institute), also known as high strenght low alloy (hsla), are used in the manufacture of these pipes, as they have, with their welded joints, mechanical properties to withstand the working conditions to which these ducts will be submitted . The objective of this study is to evaluate the fatigue behavior in microalloyed steel grade API 5L X80 welded by process HF / ERW . For this, axial fatigue tests to obtain S-N curve (stress vs. number of cycles ) were conducted. To complement the study, it was performed metallographic , fractographic , Vickers hardness tests and tensile tests to characterize the mechanical properties of the steel and check whether the values satisfy the specifications of the API 5L standard . From the fatigue tests , it was concluded that the surface finish influences directly on the fatigue life of the material

Extensometria: estudo das microdeformações ao redor de três implantes de hexágono interno, com posicionamento linear, sob a influência da fundição de coifas plásticas e usinadas

The objective of this in vitro study was quantify the micro strain development around the internal hexagon implants, varying the type of prosthetic coping. For This reason, three implants of internal hexagon were inserted into one polyurethane block in line placement. Microunit abutments were screwed onto the implants. Tangentially the implants were bonded the strain gauges, two to the center implant. Ten structures, each one containing three copings were cast in Co-Cr alloy, that were divided into groups in the first group, plastic copings were used, and in the second group machined copings were used. The superstructure’s occlusal screws were tightened onto Microunit abutments with 10 Ncm torque, the magnitude of micro strain was recorded. The mean values of each strain gauge of each plastic copings were 363,37 ± 237,66 and the machined copings were 338,12 ± 223,01. The data were analyzed statistically by t- Student test. No statistically significant difference was found between the prosthetic copings (p= 0,867). It was concluded that to internal hexagon implants in line placement, the type of copings presented similar magnitude of micro strain after prosthetic occlusal screw was tightened

Monitoramento da condição da ferramenta de dressagem usando sinais de vibração e modelos neurais

Pós-graduação em Engenharia Elétrica - FEB