4,447 research outputs found
Delineamento de experimentos utilizando as tecnicas de Taguchi para formulação de massa ceramica
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro TecnologicoDesenvolvimento e aplicação das técnicas de delineamento estatístico de experimentos aplicadas à formulação de massa cerâmica para pavimento. Utilização da metodologia de Taguchi em revestimento cerâmico de monoqueima. Estudo de propriedades físico-mecânicas de matérias primas cerâmicas. Otimização da formulação
Using Taguchi method to optimize welding pool of dissimilar laser welded components
No full textIn the present work CO2 continuous laser welding process was successfully applied and optimized for joining a dissimilar AISI 316 stainless steel and AISI 1009 low carbon steel plates. Laser power, welding speed, and defocusing distance combinations were carefully selected with the objective of producing welded joint with complete penetration, minimum fusion zone size and acceptable welding profile. Fusion zone area and shape of dissimilar austenitic stainless steel with ferritic low carbon steel were evaluated as a function of the selected laser welding parameters. Taguchi approach was used as statistical design of experiment (DOE) technique for optimizing the selected welding parameters in terms of minimizing the fusion zone. Mathematical models were developed to describe the influence of the selected parameters on the fusion zone area and shape, to predict its value within the limits of the variables being studied. The result indicates that the developed models can predict the responses satisfactorily
Parameter optimization by Taguchi Methods for finishing advanced ceramic balls using a novel eccentric lapping machine
No full textThe final finishing process of advanced ceramic balls used in hybrid precision bearings constitutes two-thirds of the total manufacturing cost, and hence effective and economic finishing methods and processes are critical to their widespread application. A novel eccentric lapping machine is designed and manufactured. Hot isostatically pressed silicon nitride ball blanks (diameter 13.25 mm) are used to investigate the feasibility of accelerating the ball finishing process while maintaining high surface quality. Taguchi methods are used during the first step of finishing to optimize lapping parameters; the L9 (3(4)) four-parameter, three-level orthogonal array is used to design the experiment. Experimental results reveal that this novel eccentric lapping method is very promising; a material removal rate of 40 mum/h is achievable. The optimum lapping condition is found to be high speed, high load and high paste concentration with 60 mum diamond particles. The analysis of variance shows that the most significant lapping parameter is lapping load, which accounts for 50 per cent of the total, followed by lapping speed (31 per cent); the particle size and paste concentration only account for 12 per cent and 7 per cent respectively. A comparison with previous lapping experiments and the mechanism of material removal are also discussed briefly
Custos da qualidade : planejamento economico dos graficos de controle por atributos e modelos correlatos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro TecnologicoRevisão e análise dos modelos de planejamento econômico dos gráficos de controle por atributos e modelos correlatos existentes. Agrupamento dos modelos em conjuntos de enfoques semelhantes, com base, especialmente, na formulação da função custo/perda, seus pressupostos básicos e número de parâmetros de custo/risco envolvidos. Indicação do modelo que melhor se adapta às necessidades, características e capacidades de um sistema produtivo. Instruções adicionais, para a tomada de decisão, com base em análise de sensibilidade dos modelos. Estudo comparativo entre o modelo de Taguchi e outros que lhe são compatíveis
Optimization of tensile strength of ferritic / austenitic laser welded components
No full textFerritic/Austenitic (F/A) joints are a popular dissimilar metals combination used in many applications. F/A joints are usually produced using conventional processes. Laser beam welding (LBW) has recently been successfully used for the production of F/A joints with suitable mechanical properties. In this study, a statistical design of experiment (DOE) was used to optimise selected laser beam welding parameters (laser power, welding speed, and focus length). The Taguchi approach was used for the selected factors, each having five levels (L-25; 5*3). Joint strength was determined using the notched tension strength (NTS) method. The results were analysed using analyses of variance (ANOVA) and the signal-to-noise ratios (S/N) ratio for the optimal parameters, and then compared with the base material. The experimental results indicate that the F/A laser welded joints are improved effectively by optimizing the input parameters using the Taguchi approach
Low-energy excitations in the electron-doped metal phtalocyanine LiO.5MnPc from Li and 1H NMR
No full textNMR and magnetization measurements in Li0.5MnPc (Pc=C32H16N8), recently proposed as a strongly correlated metal, are presented. Two different low-frequency dynamics are evidenced. The first one, probed by 1H nuclei, gives rise to a slowly relaxing magnetization at low temperature and is associated with the freezing of MnPc S=3/2 spins. This dynamics is similar to the one observed in pristine beta-MnPc and originates from Li-depleted chain segments. The second one, evidenced by the 7Li spin-lattice relaxation rate, is associated with the hopping of the electrons along Li-rich chains. The characteristic correlation times for the two dynamics are derived, and the role of the disorder is briefly discussed
An investigation and analysis of Process Parameters for EDM Drilling machine using Taguchi method
No full textNot availabl
A hierarchical Bayesian approach to robust parameter design.
No full textThe goal of robust parameter design experiments is to identify significant location and dispersion factors that can be used to set the mean response at the target level and to decrease the sensitivity of the response to uncontrolled noise factors. We present a hierarchical Bayesian model and use empirical Bayes priors to find the active factors and to get reliable estimates of the location and dispersion parameters. The approach is particularly useful when the design points are not replicated, a case which is challenging with standard procedures.Bayesian; Credibility or posterior probability intervals; Design; Empirical Bayes priors; Factors; Gibbs sampling; Hierarchical Bayesian model; Location and dispersion factors; Model; Noise; Parameters; Sensitivity; Taguchi experiments; WinBUGS;
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