The Experts below are selected from a list of 3846 Experts worldwide ranked by ideXlab platform

Durval Uchoas Braga - One of the best experts on this subject based on the ideXlab platform.

  • A tecnica de minima quantidade de fluido de corte aplicada no processo de furação de uma liga de aluminio-silicio
    2017
    Co-Authors: Durval Uchoas Braga
    Abstract:

    Resumo: Nessa última década, muito se tem pesquisado sobre a restrição ao uso de fluidos de corte na produção metal-mecânica. Os fatores importantes que justificam tal procedimento incluem a elevada parcela dos custos dos mesmos (até 17%) nos custos operacionais da fabricação, as questões ecológicas, as exigências legais quanto à preservação do meio-ambiente, à saúde do serhumano etc. Considerando-se os padrões das indústrias automotivas alemãs, para o ano de 1992, o volume de descartes de fluido de corte emulsionável representou aproximadamente 60% do consumo total de lubrificantes no país (1.151.312 tlano). Esse tipo de fluido de corte é importante não somente por refrigerar e/ou lubrificar a região do corte, mas devido ao grande volume aplicado por jato, contribuindo ainda para a remoção do cavaco e manutenção das tolerâncias dimensionais e de forma, tanto do produto como da máquina-ferramenta. É importante salientar que a aplicação de fluido de corte atomizado (mistura ar-óleo) tem sido possível em processos de fabricação por usinagem, graças ao desenvolvimento tecnológico de novos materiais para as ferramentas de corte e também das máquinas-ferramentas. O objetivo deste trabalho foi testar o desempenho do processo de furação de uma liga de alumínio-silício (7,11% Si) quando utilizado fluido de corte atomizado em comparação com o fluido de corte emulsionado. Os ensaios foram realizados utilizando-se brocas inteiriças de metal duro, tipo KI0, com diâmetro d = 10 mm. Os resultados mostraram que a operação, quando utilizado fluido de corte atomizado com vazão de óleo de 10 ml/h, apresentou um desempenho em termos de qualidade dos furos (tolerância dimensional e rugosidade) e desgaste da ferramenta similar àquele da operação com fluido decorte emulsionado aplicado em abundância por jato. Por outro lado, em termos de esforços de corte (força de avanço e potência de corte), a operação com fluido de corte atomizado se apresentou mais eficazAbstract: In the last decade a lot has been researched about the minimization of the use of cutting fluid in metal-mechanical production. Among the most important factors to justify such procedure are the high percentage of cutting fluid costs (up to 17%) in the total production costs, ecological issues, legal demands concerning to the environment, human health and so on. Considering the German pattern of its automotive companies for 1992, the volume of cutting fluid (emulsions) residuaIs represented around 60% of the total consumption of lubricants of the country (1,151,312 t/year). Cutting fluid is important not just to cool and/or to lubricate cutting zone but, due to the high volume of the fluid jet, it also contributes to the chip removal and to keep tight geometric and dimensional tolerances of the workpiece and machine tool. It is important to note that the application of atomized cutting fluid (air-oil mist) has become possible in machining processes, due to the development of new tool materials and machine tools. The main goal of this work is to evaluate the performance of a Aluminum-Silicon Alloy (7.111% of Si) drilling process when air-oil mist is used as cutting fluid in comparison with a flood of oil-water emulsion. Several experiments were carried out using solid carbide (ISO KI0) drill with diameter d = 10 mm. The results proved that the operation with air-oil mist presented similar performance in terms of quaIity of the holes (dimensional tolerances and surface roughness) and tool wear than when a flood of emulsion was applied. In the other hand, in terms of cutting forces (feed force and power) the operation using air-oil mist presented a better performanc

  • A tecnica de minima quantidade de fluido de corte aplicada no processo de furação de uma liga de aluminio-silicio
    Universidade Estadual de Campinas. Faculdade de Engenharia Mecânica, 2001
    Co-Authors: Durval Uchoas Braga
    Abstract:

    Nessa última década, muito se tem pesquisado sobre a restrição ao uso de fluidos de corte na produção metal-mecânica. Os fatores importantes que justificam tal procedimento incluem a elevada parcela dos custos dos mesmos (até 17%) nos custos operacionais da fabricação, as questões ecológicas, as exigências legais quanto à preservação do meio-ambiente, à saúde do ser humano etc. Considerando-se os padrões das indústrias automotivas alemãs, para o ano de 1992, o volume de descartes de fluido de corte emulsionável representou aproximadamente 60% do consumo total de lubrificantes no país (1.151.312 tlano). Esse tipo de fluido de corte é importante não somente por refrigerar e/ou lubrificar a região do corte, mas devido ao grande volume aplicado por jato, contribuindo ainda para a remoção do cavaco e manutenção das tolerâncias dimensionais e de forma, tanto do produto como da máquina-ferramenta. É importante salientar que a aplicação de fluido de corte atomizado (mistura ar-óleo) tem sido possível em processos de fabricação por usinagem, graças ao desenvolvimento tecnológico de novos materiais para as ferramentas de corte e também das máquinas-ferramentas. O objetivo deste trabalho foi testar o desempenho do processo de furação de uma liga de alumínio-silício (7,11% Si) quando utilizado fluido de corte atomizado em comparação com o fluido de corte emulsionado. Os ensaios foram realizados utilizando-se brocas inteiriças de metal duro, tipo KI0, com diâmetro d = 10 mm. Os resultados mostraram que a operação, quando utilizado fluido de corte atomizado com vazão de óleo de 10 ml/h, apresentou um desempenho em termos de qualidade dos furos (tolerância dimensional e rugosidade) e desgaste da ferramenta similar àquele da operação com fluido de corte emulsionado aplicado em abundância por jato. Por outro lado, em termos de esforços de corte (força de avanço e potência de corte), a operação com fluido de corte atomizado se apresentou mais eficazIn the last decade a lot has been researched about the minimization of the use of cutting fluid in metal-mechanical production. Among the most important factors to justify such procedure are the high percentage of cutting fluid costs (up to 17%) in the total production costs, ecological issues, legal demands concerning to the environment, human health and so on. Considering the German pattern of its automotive companies for 1992, the volume of cutting fluid (emulsions) residuaIs represented around 60% of the total consumption of lubricants of the country (1,151,312 t/year). Cutting fluid is important not just to cool and/or to lubricate cutting zone but, due to the high volume of the fluid jet, it also contributes to the chip removal and to keep tight geometric and dimensional tolerances of the workpiece and machine tool. It is important to note that the application of atomized cutting fluid (air-oil mist) has become possible in machining processes, due to the development of new tool materials and machine tools. The main goal of this work is to evaluate the performance of a Aluminum-Silicon Alloy (7.111% of Si) drilling process when air-oil mist is used as cutting fluid in comparison with a flood of oil-water emulsion. Several experiments were carried out using solid carbide (ISO KI0) drill with diameter d = 10 mm. The results proved that the operation with air-oil mist presented similar performance in terms of quaIity of the holes (dimensional tolerances and surface roughness) and tool wear than when a flood of emulsion was applied. In the other hand, in terms of cutting forces (feed force and power) the operation using air-oil mist presented a better performanc

Braga, Durval Uchoas - One of the best experts on this subject based on the ideXlab platform.

  • A tecnica de minima quantidade de fluido de corte aplicada no processo de furação de uma liga de aluminio-silicio
    [s.n.], 2018
    Co-Authors: Braga, Durval Uchoas
    Abstract:

    Orientador: Anselmo Eduardo DinizTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecanicaResumo: Nessa última década, muito se tem pesquisado sobre a restrição ao uso de fluidos de corte na produção metal-mecânica. Os fatores importantes que justificam tal procedimento incluem a elevada parcela dos custos dos mesmos (até 17%) nos custos operacionais da fabricação, as questões ecológicas, as exigências legais quanto à preservação do meio-ambiente, à saúde do ser humano etc. Considerando-se os padrões das indústrias automotivas alemãs, para o ano de 1992, o volume de descartes de fluido de corte emulsionável representou aproximadamente 60% do consumo total de lubrificantes no país (1.151.312 tlano). Esse tipo de fluido de corte é importante não somente por refrigerar e/ou lubrificar a região do corte, mas devido ao grande volume aplicado por jato, contribuindo ainda para a remoção do cavaco e manutenção das tolerâncias dimensionais e de forma, tanto do produto como da máquina-ferramenta. É importante salientar que a aplicação de fluido de corte atomizado (mistura ar-óleo) tem sido possível em processos de fabricação por usinagem, graças ao desenvolvimento tecnológico de novos materiais para as ferramentas de corte e também das máquinas-ferramentas. O objetivo deste trabalho foi testar o desempenho do processo de furação de uma liga de alumínio-silício (7,11% Si) quando utilizado fluido de corte atomizado em comparação com o fluido de corte emulsionado. Os ensaios foram realizados utilizando-se brocas inteiriças de metal duro, tipo KI0, com diâmetro d = 10 mm. Os resultados mostraram que a operação, quando utilizado fluido de corte atomizado com vazão de óleo de 10 ml/h, apresentou um desempenho em termos de qualidade dos furos (tolerância dimensional e rugosidade) e desgaste da ferramenta similar àquele da operação com fluido de corte emulsionado aplicado em abundância por jato. Por outro lado, em termos de esforços de corte (força de avanço e potência de corte), a operação com fluido de corte atomizado se apresentou mais eficazAbstract: In the last decade a lot has been researched about the minimization of the use of cutting fluid in metal-mechanical production. Among the most important factors to justify such procedure are the high percentage of cutting fluid costs (up to 17%) in the total production costs, ecological issues, legal demands concerning to the environment, human health and so on. Considering the German pattern of its automotive companies for 1992, the volume of cutting fluid (emulsions) residuaIs represented around 60% of the total consumption of lubricants of the country (1,151,312 t/year). Cutting fluid is important not just to cool and/or to lubricate cutting zone but, due to the high volume of the fluid jet, it also contributes to the chip removal and to keep tight geometric and dimensional tolerances of the workpiece and machine tool. It is important to note that the application of atomized cutting fluid (air-oil mist) has become possible in machining processes, due to the development of new tool materials and machine tools. The main goal of this work is to evaluate the performance of a Aluminum-Silicon Alloy (7.111% of Si) drilling process when air-oil mist is used as cutting fluid in comparison with a flood of oil-water emulsion. Several experiments were carried out using solid carbide (ISO KI0) drill with diameter d = 10 mm. The results proved that the operation with air-oil mist presented similar performance in terms of quaIity of the holes (dimensional tolerances and surface roughness) and tool wear than when a flood of emulsion was applied. In the other hand, in terms of cutting forces (feed force and power) the operation using air-oil mist presented a better performanceDoutoradoDoutor em Engenharia Mecânic

Yan Shen - One of the best experts on this subject based on the ideXlab platform.

  • anti wear property of Aluminum Silicon Alloy treated by chemical etching mechanical honing and laser finishing
    Materials, 2019
    Co-Authors: Fengming Du, Chengdi Li, Zetian Mi, Yan Shen, Ruoxuan Huang, Yong Dong, Jiujun Xu
    Abstract:

    To enhance the anti-wear property of Aluminum–Silicon (Al–Si) Alloy, three processing technologies—chemical etching, mechanical honing and laser finishing—were compared in terms of their effects on anti-wear performance. The treated Al–Si Alloy cylinder liner samples were worn against a piston ring by a reciprocating sliding tribotester; the anti-wear performance was represented by the friction coefficient and wear loss; and the wear mechanism was determined by establishing stress contact models. The results showed that the best time for both the chemical etching and mechanical honing treatments was 2 min, and the optimal laser power was 1000 W for the laser finishing treatment. The three processing technologies could all remove the Aluminum layer and make the Silicon protrude on the surface to avoid the plastic flow of Aluminum during the friction process. The laser finishing could not only protrude the Silicon particle but also make its edge rounded and smooth, which decreased the stress concentration. Therefore, the Al–Si Alloy cylinder liner treated with laser finishing had the best anti-wear performance.

  • Anti-Wear Property of Aluminum–Silicon Alloy Treated by Chemical Etching, Mechanical Honing and Laser Finishing
    MDPI AG, 2019
    Co-Authors: Yan Shen, Ruoxuan Huang, Xiaoguang Han, Yong Dong
    Abstract:

    To enhance the anti-wear property of Aluminum–Silicon (Al–Si) Alloy, three processing technologies—chemical etching, mechanical honing and laser finishing—were compared in terms of their effects on anti-wear performance. The treated Al–Si Alloy cylinder liner samples were worn against a piston ring by a reciprocating sliding tribotester; the anti-wear performance was represented by the friction coefficient and wear loss; and the wear mechanism was determined by establishing stress contact models. The results showed that the best time for both the chemical etching and mechanical honing treatments was 2 min, and the optimal laser power was 1000 W for the laser finishing treatment. The three processing technologies could all remove the Aluminum layer and make the Silicon protrude on the surface to avoid the plastic flow of Aluminum during the friction process. The laser finishing could not only protrude the Silicon particle but also make its edge rounded and smooth, which decreased the stress concentration. Therefore, the Al–Si Alloy cylinder liner treated with laser finishing had the best anti-wear performance

  • Friction Performance of Aluminum-Silicon Alloy Cylinder Liner after Chemical Etching and Laser Finishing
    MDPI AG, 2019
    Co-Authors: Ruoxuan Huang, Xiaoguang Han, Yan Shen
    Abstract:

    In order to enhance the surface friction performance of the Aluminum-Silicon (Al-Si) Alloy cylinder liner, chemical etching and laser finishing techniques are applied to improve the friction performance. The cylinder liner samples are worn against a Cr-Al2O3 coated piston ring by a reciprocating sliding tribotester. The friction coefficient and weight loss are measured to determine the friction performance; a stress contact model is developed to ascertain the wear mechanism. The results show that the optimal etching time is 2 min for the chemical etching treatment and the optimal laser power is 1000 W for the laser finishing treatment. The chemical etching removes the surface Aluminum layer and exposes the Silicon on the surface, thereby avoiding metal-to-metal contact. The laser finishing results in the protrusion and rounded edges of the Silicon particles, which decreases the stress concentration. The laser finishing results in better friction performance of Aluminum-Silicon Alloy cylinder liner than the chemical etching

L I Kobeleva - One of the best experts on this subject based on the ideXlab platform.

  • laser ultrasonic nondestructive evaluation of porosity in particulate reinforced metal matrix composites
    Ultrasonics, 2019
    Co-Authors: N B Podymova, I E Kalashnikov, L K Bolotova, L I Kobeleva
    Abstract:

    Abstract In this work, we propose the laser-ultrasonic method for nondestructive evaluation of porosity in particulate reinforced metal-matrix composites fabricated by stir and in-situ reactive casting techniques. The method is based on the influence of porosity on dispersion of the phase velocity of longitudinal acoustic waves, which is measured by the broadband acoustic spectroscopy with laser excitation of ultrasound (laser-ultrasonic spectroscopy). We studied stir cast hypereutectic Aluminum-Silicon Alloy A336 matrix composites reinforced with the SiC micro particles (3.3–13.5 vol%) and in-situ reactive cast Al/Al3Ti composites reinforced with the Al3Ti intermetallic particles (4–11.5 vol%). In the spectral range of 3–40 MHz, the phase-velocity dispersion in both types of composites was observed: the high-frequency velocity in the range of 20–40 MHz increases with the increase of the reinforcement content independent of porosity, whereas the low-frequency velocity in the range of 3–10 MHz decreases with the increase of porosity independent of the reinforcement content. As a result, the relative dispersion grows up with the increase in the composite porosity independent of the variation in the reinforcement content. The empirical dependence between the porosity in a scanning composite region and the relative phase-velocity dispersion in this region is approximated by the same unified function. For the first time, such unified porosity-phase velocity functional relationship is obtained for particulate reinforced metal-matrix composites completely different in fabrication techniques as well as in chemical composition and elastic properties of reinforcing particles.

Helson Kyle - One of the best experts on this subject based on the ideXlab platform.

  • The CLASS 150/220 GHz Polarimeter Array: Design, Assembly, and Characterization
    'Springer Science and Business Media LLC', 2020
    Co-Authors: Dahal Sumit, Amiri Mandana, Appel, John W., Bennett, Charles L., Corbett Lance, Datta Rahul, Denis Kevin, Essinger-hileman Thomas, Halpern Mark, Helson Kyle
    Abstract:

    We report on the development of a polarization-sensitive dichroic (150/220 GHz) detector array for the Cosmology Large Angular Scale Surveyor (CLASS) delivered to the telescope site in June 2019. In concert with existing 40 and 90 GHz telescopes, the 150/220 GHz telescope will make observations of the cosmic microwave background over large angular scales aimed at measuring the primordial B-mode signal, the optical depth to reionization, and other fundamental physics and cosmology. The 150/220 GHz focal plane array consists of three detector modules with 1020 transition edge sensor (TES) bolometers in total. Each dual-polarization pixel on the focal plane contains four bolometers to measure the two linear polarization states at 150 and 220 GHz. Light is coupled through a planar orthomode transducer (OMT) fed by a smooth-walled feedhorn array made from an Aluminum-Silicon Alloy (CE7). In this work, we discuss the design, assembly, and in-lab characterization of the 150/220 GHz detector array. The detectors are photon-noise limited, and we estimate the total array noise-equivalent power (NEP) to be 2.5 and 4 aW$\sqrt{\mathrm{s}}$ for 150 and 220 GHz arrays, respectively.Comment: 8 pages, 5 figures, Published in J Low Temp Phy