• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.43-44
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• 2005

SU-8 is a epoxy based photoresist designed for MEMS applications, where a thick, chemically and thermally stable image is desired. But SU-8 has proven to be very sensitive to variation in processing variables and hence difficult to use in the fabrication of useful structures. In this paper, negative SU-8 photoresist processed has been characterized in terms of delamination. Based on a full factorial designed experiment. Employing the design of experiment (DOE), a process parameter is established, and analyzing of full factional design is generated to investigate degree of delamination associated with three process parameters: post exposure bake (PEB) temperature, PEB time, and exposure energy. These results identify acceptable ranges of the three process variables to avoid delamination of SU-8 film, which in turn might lead to potential defects in MEMS device fabrication.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.51-57
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• 2019

To protect the Cu surface from oxidation in air, a two-step plasma process using Ar and $N_2$ gases was studied to form a copper nitride passivation as an anti-oxidant layer. The Ar plasma removes contaminants on the Cu surface and it activates the surface to facilitate the reaction of copper and nitrogen atoms in the next $N_2$ plasma process. This study investigated the effect of Ar plasma on the formation of copper nitride passivation on Cu surface during the two-step plasma process through the full factorial design of experiment (DOE) method. According to XPS analysis, when using low RF power and pressure in the Ar plasma process, the peak area of copper oxides decreased while the peak area of copper nitrides increased. The main effect of copper nitride formation in Ar plasma process was RF power, and there was little interaction between plasma process parameters.

• Corrosion Science and Technology
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• v.22 no.3
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• pp.201-213
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• 2023

Corrosion management of an aircraft and its engine relies on rinsing and cleaning using tap water. Few studies have reported effects of tap water species on corrosion behaviors of structural materials. In this study, a series of experiments were conducted based on the design of experiment. Solutions with different levels of chloride and sulfate ions were prepared using a full factorial design. Two structural materials (aluminum alloy and steel) were used for an alternate immersion test. Weight loss was then measured. In addition, a silver specimen was utilized as a sensor for chloride deposition measurement. The silver specimen was examined using the electrochemical reduction method, XPS, and SEM-EDS. Surface analysis revealed that levels of chloride and sulfate ions were sufficient for the formation of silver chloride and silver surface. Statistical analysis of weight loss and chloride deposition rate showed significant differences in measured values. Concentration of chloride ions greatly affected corrosion behaviors of structural materials. Sulfate ion hindered the adsorption reaction. These results emphasize the importance of controlling ion concentration of tap water used for cleaning and rinsing an aircraft.

• Corrosion Science and Technology
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• v.20 no.2
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• pp.52-61
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• 2021

This study using experimental design and linear regression technique was implemented in order to predict the pitting potential of stainless steel in marine environments, with the target materials being AL-6XN and STS 316L. The various variables (inputs) which affect stainless steel's pitting potential included the pitting resistance equivalent number (PRNE), temperature, pH, Cl^- concentration, sulfate levels, and nitrate levels. Among them, significant factors affecting pitting potential were chosen through an experimental design method (screening design, full factor design, analysis of variance). The potentiodynamic polarization test was performed based on the experimental design, including significant factor levels. From these testing methods, a total 32 polarization curves were obtained, which were used as training data for the linear regression model. As a result of the model's validation, it showed an acceptable prediction performance, which was statistically significant within the 95% confidence level. The linear regression model based on the full factorial design and ANOVA also showed a high confidence level in the prediction of pitting potential. This study confirmed the possibility to predict the pitting potential of stainless steel according to various variables used with experimental linear regression design.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.482-489
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• 2011

In practical design process, designer needs to find an optimal solution by using full factorial discrete combination, rather than by using optimization algorithm considering continuous design variables. So, ANOVA(Analysis of Variance) based on an orthogonal array, i.e. Taguchi method, has been widely used in most parts of industry area. However, the Taguchi method is limited for the shape optimization by using CAE, because the multi-level and multi-objective optimization can't be carried out simultaneously. In this study, a combined method was proposed taking into account of multi-level computational orthogonal array and TOPSIS(Technique for Order preference by Similarity to Ideal Solution), which is known as a classical method of multiple attribute decision making and enables to solve various decision making or selection problems in an aspect of multi-objective optimization. The proposed method was applied to a case study of the multi-level shape optimization of lower arm used to automobile parts, and the design space was explored via an efficient application of the related CAE tools. The multi-level shape optimization was performed sequentially by applying both of the neural network model generated from seven-level four-factor computational orthogonal array and the TOPSIS. The weight and maximum stress of the lower arm, as the objective functions for the multi-level shape optimization, showed an improvement of 0.07% and 17.89%, respectively. In addition, the number of CAE carried out for the shape optimization was only 55 times in comparison to full factorial method necessary to 2,401 times.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.230-230
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• 2009

가스절연 개폐장치 (Gas Insulated Switchgear : GIS)의 고체 스페이서에 경사 기능성 재료 (Functionally Graded Material : FGM)가 적용될 때, 절연성능이 크게 향상된다. 본 논문에서는 FGM 스페이서가 적용된 GIS의 전극 및 스페이서의 형상을 변경하여 최대전계를 완화시켰다. 이를 위해 완전요인실험 (Full Factorial Design : FFD)과 결합된 반응표면법 (Response Surface Methodology : RSM)의 최적화기법을 이용하여, 전극 및 스페이서의 최적 형상을 설계하였다.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.172-178
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• 2011

This paper presents an optimization procedure for high-efficiency design of a mixed-flow pump. Optimization techniques based on a weighted-average surrogate model are used to optimize a vane diffuser of a mixed-flow pump. Validation of the numerical results is performed through experimental data for head, power and efficiency. Three-level full factorial design is used to generate nine design points within the design space. Three-dimensional Reynoldsaveraged Navier-Stokes equations with the shear stress transport turbulence model are discretized by using finite volume approximation and solved on hexahedral grids to evaluate the efficiency as the objective function. In order to reduce pressure loss in the vane diffuser, two variables defining the straight vane length ratio and the diffusion area ratio are selected as design variables in the present optimization. As the results of the design optimization, the efficiency at the design flow coefficient is improved by 7.05% and the off-design efficiencies are also improved in comparison with the reference design.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.28-33
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• 2011

In this paper, structural design for 2kW class composite blade is performed by using design of experiment(DOE). A full factorial design is applied to meet the design specifications at the manufacturing process. The analysis of variance(ANOVA) is made in order to determine the significance of effects in an analysis. Structural analysis by using of commercial software ABAQUS is performed to compute the displacement and safety factor of filament wound composite blade. The results show that the proposed method is suitable to analyze the factors at the design of wind turbine blade.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.131-138
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• 1998

In order to minimize the trial frequency in the new filter cigarette design, we studied the relationship between smoke yield and tipping materials of cigarette. A three levels full factorial design involving filament denier (X1,2.5-3.3d), Porosity of the acetate filter plug wrap (X2, 3,500-16,000CU) and porosity of the tip paper (X3, 400-1,200CU) was used. Three independent factors (Xl, X2, X3) were chosen for their effects on the various responses and the function was expressed in terms of a quadratic polynomial equation, Y : $\beta$o + $\beta$1Xl + $\beta$2X2 + $\beta$3X3 + $\beta$11Xl2 + $\beta$22X22+ $\beta$33X32 + $\beta$12X1X2 + $\beta$13XIX3 $\beta$23X2X3 which measures the linear, quadratic, and interaction effects. Twenty-nine trial numbers were obtained as a results of using a three levels full factorial design and it was analyzed by the multiple regression analysis with backward stepwise in STATISTICA/pc under restricted conditions. Tar yields of the cigarette was affected by porosity of tip paper (0.66), filament denier (0.47) and porosity of plug wrap (0.28) in the decreasing order, and linear effect of tip paper porosity (B3) and filament denier (91) were significant at a level of 0.01($\alpha$). The filament denier and tipping paper porosity interaction F ratio among three factors had a P-value of 0,000041, indicating higher interaction between these factors. Based on the analysis of variance, the model fitted for Tar (Y1) was significant at 5% confidence level and the coefficient of determination (0.96) was the proportion of variability in the data fitted for by the model.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.439-443
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• 2002

In this study, three-dimensional incompressible viscous flow analysis and optimization using response surface method are presented for the design of a jet fan. Steady, incompressible, three-dimensional Reynolds averaged Wavier-Stokes equations are used as governing equations, and standard k-$\epsilon$ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Sweep angles and maximum thickness of blade are used as design variables for the shape optimization of the impeller in response surface method. The experimental points which are needed to construct response surface are obtained from the D-optimal design and Full Factorial design and relations between design variables and response surface are examined.