Papers by Keyword: Analysis of Variance (ANOVA)

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Authors: U. Shrinivas Balraj, P. Anitha, A. Gopalakrishna
Abstract: In this paper, rotary electrical discharge machining of RENE 80 nickel super alloy is carried out to study the effect of process parameters like peak current, pulse on time, pulse off time and rotational speed of electrode on surface integrity characteristics like white layer thickness and surface crack density. The number of experiments, optimum levels of the parameters and their effects are studied using Taguchi method. The significant process parameters are identified using analysis of variance. It is found that the responses are affected mainly by peak current and pulse on time. The experimental results reveal that white layer thickness increases with increase of peak current and pulse on time whereas the surface crack density decreases with increase of peak current and pulse on time.
Authors: Li Fa Han, Wei Xia, Yuan Yuan Li, Wei Ping Chen
Abstract: This paper presents an investigation on the surface roughness of burnished hypereutectic Al-Si alloy ¾ a widely used light-weight and wear resistant material in automobile, electric and aircraft industries. Based on the techniques of Taguchi, an orthogonal experiment plan with the analysis of variance (ANOVA) is performed and a second-order regressive mathematical model is established. Meanwhile, the influence of process parameters on surface roughness and its mechanism are discussed. From the experiments, it is found that burnishing process is effective to decrease surface roughness of hypereutectic Al-Si alloy components, in which, all input parameters have a significant effect on the surface roughness. To achieve a small surface roughness, the optimum process parameters are recommended.
Authors: P. Padmini, S. Senthamilperarasu, B. Shanmuganathan, N.R.R. Anbusagar, P. Sengottuvel
Abstract: Electrical-discharge Machining (EDM) is a nonconventional machining process utilizing an electric spark discharge from the electrode (-) towards the work piece (+) through the dielectric fluid. The Dimensional accuracy in this is very important consideration for the accuracy of the finished product. The objective of this experimental study is to determine parameters that offer the best dimensional accuracy in electrical discharge machining (EDM). Discharge current (A), Pulse On Time (Ton), Pulse Off Time (Toff ) and Circle,Rectangle,Triangle and Square Tool Geometrical Shapes (Geo) are taken as machining parameters. The experimental investigations are carried out on Monel 400 material using Tungsten copper electrode. The response of ROC is considered for improving the machining efficiency. Optimal combination of parameters was obtained Taguchi Optimization technique. The confirmation experiments results shows that the significant improvement in Radial Overcut was obtained. ANOVA have been used to analyze the contribution of individual parameters on ROC. The experimental result demonstrates that the Taguchi method satisfies the practical requirements
Authors: Liang Liang Che, Xue Han
Abstract: Water consumption per ten thousand yuan GDP (WG) is an internationally comparative indicator of water use efficiency (WE), but it cannot further reveal the causes of the differences of WE. The shift-share analysis method is introduced, and the WG-shift-share analysis model (WG-SSM) is built combined with the regression model. According to the model, WE is decomposed and analyzed from the three levels of the country, the region and the industry from 1997 to 2011. The results show that: WG of the country, the region and the industry shows a significant downward trend, but WE is greatly different of inter-region and inter-industry; total shift of each region relative to the national average level is shrinking year by year, and inter-regional differences are mainly due to the competitive effect; the influence of the industrial mix effect is determined by the WE of the primary industry;the allocation effect least impacts on the differences of regional WE, but it can test the interaction between the competitive effect and the industrial mix effect, which can provide objective reference for drafting the water-saving policies and measures.
Authors: Shi Lei Zhou, Ya Lin Guan, Xin Kun Tang
Abstract: This paper based on ANOVA (ANalysis Of VAriance) presents an investigation in the design of signal via in multilayered printed circuit boards (PCB) technology from a signal integrity point of view. Using the concept of the orthogonal array (OA), different vias physical aspect ratios have been set in the analysis. The impacts of these parameters are investigated with the help for a full-wave electromagnetic simulation soft HFSS. This study demonstrates the factors which is the most influence on the signal integrity.
Authors: Sandeep, Ujjwal Prakash, P.C. Tewari, Dinesh Khanduja
Abstract: The main aim of present research paper is to analyze the influence of compaction load and sintering temperature on relative density of low carbon alloy steel. The alloy steel powder has been compacted at different loads and sintering at different temperatures. The compaction of alloy steel has been done with a circular die of 20 mm internal diameter and 100 mm height at different load and sintering temperature. With the application of hydrostatic stress, the pores will be removed and relative density will increase. So, relative density value will increase simultaneously. This experimental study presents how relative density can be improved by using Powder Metallurgy route. The results are further analyzed with the help of Analysis of Variance using Design of Experiments Tool.
Authors: Peter Šugár, Jana Šugárová, Peter Zemko
Abstract: The paper presents the results of radial strain distribution measurement throughout the part after multi-pass conventional metal spinning by the circle grid analysis method. The influence of the mandrel speed, workpiece geometry and planar anisotropy of material on the radial strain was studied. For experiment design, an orthogonal array L27 was used and ANOVA (Analysis of Variance) was carried out. Based on the results it is determined that the sequence of factors affecting radial strain corresponds to geometry of spun part, mandrel speed, planar anisotropy of the sheet. In particular, it is found that the workpiece geometry (specific areas of spun part: mandrel/workpiece radius, conical area, cylindrical area) is the most important factor which influences the radial strain of the spun part.
Authors: Haw Pei Li, Norhamidi Muhamad, Abu Bakar Sulong, Heng Shye Yunn, Hooman Abolhasani
Abstract: Optimization of injection parameters in Micro Metal Injection Molding (μMIM) was described in this study. Stainless steel powder was mixed with Polyethelena Glycol (PEG), Polymethyl Methacrilate (PMMA) and Cellulose Acetate Butyrate (CAB) to produce feedstock. Design of Experiments (DOE) of Taguchi L-27 (313) orthogonal array technique has been used to investigate the significance and optimal injection molding parameters. The signal-to-noise ratio and analysis of variance (ANOVA) are applied to study the optimum levels and effects of process parameters. Simultaneous optimization to obtain the highest green density and excellent surface appearance was discussed. The result concluded that the mold temperature (D) is the most statistically significant process parameter and its contribution to the best appearance and density is the highest.
Authors: Mohd Halim Irwan Ibrahim, Norhamidi Muhamad, A.B. Sulong
Abstract: Due to its versatility, micro metal injection molding has become an alternative method in powder metallurgy where it can produce small part with a minimal number of waste. The success of micro MIM is greatly influenced by feedstock characteristics. This paper investigated the characterization and optimization which both of them plays an important characteristic in determining the successful of micro MIM. In this paper, stainless steel SS 316L was used with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid). The rheology properties are investigated using Shimadzu Flowtester CFT-500D capillary rheometer. The geometry of water atomised stainless steel powder are irregular shape, therefore it is expected significant changes in the rheological results that can influence the microcomponent, surface quality, shape retention and resolution capabilities. From rheological characteristics, feedstock with 61.5% shows a significant value with several injection parameters were optimized through screening experiment such as injection pressure (A), injection temperature (B), mold temperature (C), injection time (D) and holding time (E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchis orthogonal array. Result shows that 61.5%vol contributes a significant stability over a range of temperature and the best powder loading from a critical powder volume percentage (CPVP) and rheological point of view. Furthermore interaction between injection temperature and mold temperature (BxC) give highest significant factor followed by interaction between injection pressure and mold temperature (AxC).
Authors: Mohammad Reza Shabgard, Babak Sadizadeh, Keivan Amini, Hamid Pourziaie
Abstract: The correct selection of the machining parameters is one of the most significant issues to take into consideration in Ultrasonic-assisted Electrical Discharge Machining (US-EDM) and EDM processes. In the present work, a study has been made to develop and extract statistical models to show the relationship between important machining performance data (material removal rate (MRR), tool wear ratio (TWR) and surface roughness Ra) and the input machining parameters (pulse current, and pulse-on time) in the EDM and US-EDM of AISI H13. The models obtained were used to analyze the effects of input parameters on machining performance. In addition, a comparative study was carried out to investigate the effect of ultrasonic vibration of the workpiece on machining performance. The results show that Ultrasonic vibration of the workpiece can significantly reduce the inactive pulses and improves the stability of process. Also US-EDM is effective in attaining a high material removal rate (MRR) in finishing regime in comparison with conventional EDM. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models can adequately explain the performance within the limits of the factors being studied.
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