Papers by Keyword: Analysis of Variance (ANOVA)

Abstract: The subject of the research was to optimize the manufacturing process and heat treatment of sintered Fe-Mn-Cr-Mo-C steels in order to improve the strength properties. It can be concluded that the performed chemical composition, sintering temperature and the heat treatment have the greatest impact on the value of these properties. The sintering atmosphere has the smallest effect on the obtained properties. Increasing the sintering temperature, as well as carrying out additional heat treatment after the sintering process, increases the value of all of the analyzed properties. The optimization of the manufacturing process of the tested materials was carried out for each analyzed strength parameter separately and for all strength parameters together. The aim of the optimization was to determine the setting of the sintering process parameter levels that would allow to obtain the maximum values of the analyzed mechanical properties.

Abstract: Granular activated carbon (GAC) is utilized as an adsorbent for the malachite green (MG) dye removal from aqueous solutions. The GAC was characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) to realize the GAC chemical and physical features effects on the adsorption efficiency. Batch adsorption processes were carried out with different variables like pH, GAC dose, initial MG concentration and time. The response surface methodology (RSM) was used to design the experiments, model the adsorption process, optimize the operating conditions and predict the response. A 2⁴ full factorial central composite design (CCD) was performed for the experimental design and the analysis of the results. Analysis of variance (ANOVA) was employed to determine the significance of the factors and explore the interaction between the various experimental parameters. An empirical model was derived to correlate the experimental results and predict the behavior of the GAC for the adsorption process. The model showed a good agreement with the experimental results of R² = 0.9968 and evidenced that the optimum operating parameters are pH 10, 2 g GAC/L, 200 mg/L of MG initial concentration and 113 min adsorption time for complete removal of MG.

Abstract: Manufacturing industries have consumed 30% of the total world energy. The main energy source used in those manufacturing industries is the electricity generated from fossil fuels such as oil, gas, and coal as a result in causing the environmental and economic issues. This paper presents an experimental study in order to get the minimum energy consumption during turning of aluminum 6010 with the conventional machine tool under dry cutting condition by optimizing the cutting parameters to contribute to those issues. An analysis of variance (ANOVA) was employed to analyze the effects and contribution of depth of cut, feed, and cutting speed on the response variable, specific cutting energy. The result of this experiment showed that the feed was the most significant factor for minimizing energy consumption followed by the cutting speed and the depth of cut. The minimum energy consumption was obtained when the highest level of cutting parameters have been used.

Abstract: The aim of Manganese Phosphate coating is to convert the metallic surface completely into a non metallic surface. A Phosphating is a chemical conversion treatment which produces a porous surface layer of crystalline phosphate. High carbon high chromium steels are commonly used in applications requiring excellent wear resistance in tool and die making industries. The wear characteristic of the coated steel was evaluated through pin on disc test as per ASTM G99 standards using a sliding velocity of 3.0m/s under constant loads. Taguchi’s design of L₀₉ orthogonal array is followed selecting three parameters namely load, surface roughness, sliding distance. Optimal conditions are arrived by Signal-Noise ratio method with respect to coefficient of friction. The results are validated by analysis of variance (ANOVA) and the percentage of contribution of load, surface roughness and sliding distance for better coefficient of friction are determined.

Abstract: Increasing global competition, shrinking product life cycles, and increasing product mix are defining a new manufacturing environment in world markets. This paper presents a case problem using Taguchi Method to find optimum design parameters for a Flexible Manufacturing System (FMS). A L₈ array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) are employed to study performance characteristics of selected manufacturing system design parameters (e.g. layout, AGVs, buffers, and routings) with consideration of product mix demand. Various design and performance parameters are evaluated and compared for the original and the improved FMS. The results obtained by this method may be useful to other researchers for similar types of applications.

Abstract: Drilling is an essential secondary process for near net-shape of hybrid composite as to achieve the required dimensional tolerances prior to final application. Dimensional tolerance is often influenced by the surface integrity or surface roughness of the workpart. Thus, this paper aims to employ the Taguchi and response surface methodologies in minimizing the surface roughness of drilled carbon-glass hybrid fibre reinforced polymer (CGCG) using tungsten carbide, K20 drill bits. The effects of spindle speed, feed rate and tool geometry on surface roughness were evaluated and optimum cutting conditions for minimizing the aforementioned response was determined. Subsequently, response surface methodology (RSM) was utilised in finding the empirical relationships between experimental parameters and surface roughness based on the Taguchi results. The experimental analyses reveal that surface roughness is greatly influenced by feed rate and tool geometry rather than the spindle speed. This is due to the increment of feed that attributed to the increased strain rate and hence, deteriorated the surface roughness of the hybrid composite. The predicted results (via regression model) and theoretical results (via additivity law) were in good agreement with experiment results. This indicates that the regression model from response surface methodology (RSM) can be used to predict the surface roughness in machining of CGCG hybrid composite.

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 (T_on), Pulse Off Time (T_off ) 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

Abstract: Polymers reinforced with synthetic fibers such as glass and carbon offer advantages of high stiffness and strength to weight ratio compared to conventional materials. Despite these advantages, the prevalent use of synthetic fiber-reinforced polymer composite has a tendency to demur because of high initial cost and most importantly their adverse environmental impact. On the contrary, the increased interest in using natural fibers as reinforcement in plastics to substitute conventional synthetic fibers in automobile applications has become one of the main concerns to study the potential of using natural fibers as reinforcement for polymers. In this regard, an investigative study has been carried out to make potential utilization of natural fibers such as Jute and Coir as reinforcements, which are cheap and abundantly available in India. The objective of the present research work is to study the effects of fiber loading and particle size; fiber loading and fiber length on the mechanical properties of Jute-PP and Coir-PP bio-composites respectively. The experiments were planned as per full factorial design (FFD) and response surface methodology (RSM) based second order mathematical models of mechanical properties have been developed. Analysis of variance (ANOVA) has been employed to check the adequacy of the developed models. From the parametric analysis, it is revealed that Jute-PP bio-composites exhibit better mechanical properties when compared to Coir-PP bio-composites.

Abstract: End milling is conducted on carbon fiber reinforced plastics (CFRP) by using a diamond coated cemented carbide tool. Taguchi design method is employed to investigate the influence of cutting speed, feed rate and depth of cut on surface roughness. In Taguchi method, a three level orthogonal array has been used to determine the S/N ratio. Analysis of variance (ANOVA) and pareto diagram are used to determine the most significant milling parameters affecting the surface roughness. The results indicate that only the depth of cut has great statistical significance on the surface roughness, while the influences of cutting speed and feed are negligible. SEM micrographs shows that with the increase of depth of cut, a great deal epoxy resin will adhere to the finished surface. The greatest S/N ratio (1.46dB) is obtained during the validation experiment with optimum milling parameters.

Abstract: This study used Taguchi plasma-sprayed experiments to determine the surface wear-resistant performance optimization of yttria partially stabilized zirconia (ZrO2/8Y2O3) coatings. Eight control factors based on L18 arrays were conducted and the wear-resistant properties of coatings were evaluated in the experiments. Based on analysis of variance, the optimal settings have been identified, and response surface methodology is utilized. Further, the contour nature of the quadric function is conducted to validate the tests in the Taguchi designed experiments. The experimental results obtained show that using an experimental design strategy with the proposed quadric model is useful not only for predicted optimal process parameters to achieve a desired quality but also for process optimization. Several response plots were generated to examine parameter effects on the response profiles. In addition, microstructures of the worn surface were examined, revealing a dense texture and highly anisotropic properties in the coatings with high anti-wear behavior.