Abstract: This article presents the optimization of process parameters in friction stir welding (FSW) of Aluminum Alloy AA 5083 with multiple responses based on orthogonal array with grey relational analysis. The L9 orthogonal array of Taguchi experimental design is used for optimizing the FSW process parameters on tensile strength of FSW welds and total input power required for the process. The process parameters considered for optimization are the Rotational speed of the tool in rpm, transverse speed in mm/min, and the axial force in KN. The objective of this article is to find the optimum levels of the process parameters in which it yields maximum tensile strength and consumes minimum power. Based on the grey relational grade, optimum levels of parameters have been identified, and significant contribution of parameters is determined by ANOVA. The optimum levels of the process parameters are determined and validated by the confirmation run.

Abstract: In the present work, quadratic mathematical models have been derived to represent the process behavior of wire electrical discharge machining (WEDM) operation. Experiments have been conducted with six process parameters: discharge current, pulse duration, pulse frequency, wire speed, wire tension and dielectric flow rate; to be varied in three different levels. Data related to the process responses viz. material removal rate (MRR), roughness value of the worked surface (a measure of surface finish, SF) and kerf have been measured for each of the experimental runs; which correspond to randomly chosen different combinations of factor setting. These data have been utilized to fit a quadratic mathematical model (Response Surface Model) for each of the responses, which can be represented as a function of the aforesaid six process parameters. Predicted data have been utilized for identification of the parametric influence in the form of graphical representation for showing influence of the parameters on selected responses. Predicted data given by the models (as per Taguchi’s L27 (3*6) Orthogonal Array (OA) design) have been used in search of an optimal parametric combination to achieve desired yield of the process: maximum MRR, good surface finish (minimum roughness value) and dimensional accuracy of the product. Grey relational analysis has been adopted to convert this multi-objective criterion into an equivalent single objective function; overall grey relational grade, which has been optimized (maximized) by using Taguchi technique. Optimal setting has been verified through confirmatory test; showed good agreement to the predicted value. This indicates utility of the grey-Taguchi technique as multi-objective optimizer in the field of wire EDM. Keywords: Wire EDM; MRR; response surface methodology; Orthogonal Array (OA)

Abstract: The present work demonstrates optimization of Wire Electrical Discharge Machining process parameters of Incoloy800 super alloy with multiple performance characteristics such as Material Removal Rate (MRR), surface roughness and Kerf based on the Grey–Taguchi Method. The process parameters considered in this research work are Gap Voltage, Pulse On-time, Pulse Off-time and Wire Feed. Taguchi’s L9 Orthogonal Array was used to conduct experiments. Optimal levels of process parameters were identified using Grey Relational Analysis and the relatively significant parameters were determined by Analysis of Variance. The variation of output responses with process parameters were mathematically modelled by using non-linear regression analysis method and the models were checked for their adequacy. Result of confirmation experiments shows that the established mathematical models can predict the output responses with reasonable accuracy.

Abstract: We develop a new method for constructing “good” designs for computer experiments. The method derives its power from its basic structure that builds large designs using small designs. We specialize the method for the construction of orthogonal Latin hypercubes and obtain many results along the way. In terms of run sizes, the existence problem of orthogonal Latin hypercubes is completely solved. We also present an explicit result showing how large orthogonal Latin hypercubes can be constructed using small orthogonal Latin hypercubes. Another appealing feature of our method is that it can easily be adapted to construct other designs; we examine how to make use of the method to construct nearly orthogonal and cascading Latin hypercubes.

Abstract: We develop a new method for constructing "good" designs for computer experiments. The method derives its power from its basic structure that builds large designs using small designs. We specialize the method for the construction of orthogonal Latin hypercubes and obtain many results along the way. In terms of run sizes, the existence problem of orthogonal Latin hypercubes is completely solved. We also present an explicit result showing how large orthogonal Latin hypercubes can be constructed using small orthogonal Latin hypercubes. Another appealing feature of our method is that it can easily be adapted to construct other designs; we examine how to make use of the method to construct nearly orthogonal and cascading Latin hypercubes.

Abstract: Red mud is an industrial waste generated during the production of alumina by Bayer's process. Using this red mud as the filler, particulate reinforced polyester composites have been prepared and their dry sliding wear behavior has been studied experimentally. For this a standard pin- on-disc test set-up and Taguchi's orthogonal arrays were used. Taguchi's experimental design method eliminates the need for repeated experiments and thus saves time, materials, and cost. It identifies the significant control factors and their interactions predominantly influencing the wear rate. From the experimental findings, an optimal combination of control factors was obtained on the basis of which a predictive model was proposed. This model was validated by performing a confirmation experiment with an arbitrarily chosen set of factor combinations. Finally, the optimal factor settings for minimum wear rate under specified experimental conditions have been determined using a genetic algorithm.

Abstract: Abrasive flow machining (AFM) is gaining widespread application finishing process on difficult to reach surfaces in aviation, automobile, and tooling industry. Al/SiCp-MMC is a promising material in these industries. Here, AFM has been used to finish conventionally machined cylindrical surface of Al/15 wt% SiCp-MMC workpiece. This paper presents the utilization of robust design-based Taguchi method for optimization of AFM parameters. The influences of AFM process parameters on surface finish and material removal have been analyzed. Taguchi experimental design concept, L18 (61 × 37) mixed orthogonal array is used to determine the S/N ratio and optimize the AFM process parameters. Analysis of variance and F test values also indicates the significant AFM parameters affecting the finishing performance. The mathematical models for R a, R t, ΔR a, and ΔR t and material removal are established to investigate the influence of AFM parameters. Conformation test results verify the effectiveness of these models and optimal parametric combination within the considered range. Scanning electron micrographs testifies the effectiveness of AFM process in fine finishing of Al/15 wt% SiCp-MMC.

Abstract: In this paper, an experimental investigation into laser transmission welding of acrylics is carried out. The Taguchi method of parameter design is used as a statistical design of experiment technique to set the optimal process parameters. Experiments are designed and conducted by using Taguchi's L16 orthogonal array. Maximization of weld strength is selected as the quality target. The signal-to-noise ratio and the analysis of variance are used to find the optimum levels within the window of parameters selected and to identify the order of importance of the process parameters. With the frame of this work the effects of process parameters on weld strength is also discussed. Finally, a confirmation test is conducted, which verifies that optimal laser transmission welding parameters can be determined effectively so as to improve weld strength through the Taguchi method.

Abstract: This paper presents an approach which combines the orthogonal array experiment technique and an ant direction hybrid differential evolution algorithm (ADHDEOA) in determining the tilt angle for photovoltaic (PV) modules. In this study, an orthogonal array (OA) is first conducted to obtain the initial solution. Next, an ant direction hybrid differential evolution (ADHDE) is applied to search for a near optimum solution. The purpose of this research is to maximize the output power of the module. The sun's position at any time and location was predicted by the mathematical procedure of Julian dating; then, the solar irradiation was obtained at each site under a clear sky. The searching for global optimal solution is applied to a practical experimental system. The results show that the annual optimal angle for the Taipei area is 23.18^o; for Taichung, 22.32^o; for Tainan, 21.62^o; for Kaosiung, 20.83^o; for Hengchung, 20.27^o; for Hualian, 22.18^o; and for Taitung, 20.89^o in seven Taiwanese areas, and the actual best annual tilt angles are close to the computer simulation results.

Abstract: During high speed rolling of a nonpneumatic wheel, vibration may be produced by the interaction of collapsible spokes with a shear deformable ring as they enter the contact region, buckle, and then snap back into a state of tension. In the present work, a systematic study of the effects of six key geometric design parameters is presented using Orthogonal Arrays. Orthogonal Arrays are part of a design process method developed by Taguchi which provides an efficient way to determine optimal combinations of design variables. In the present work, a two-dimensional planar finite element model with geometric nonlinearity and explicit time-stepping is used to simulate rolling of the nonpneumatic wheel. Vibration characteristics are measured from the FFT frequency spectrum of the time signals of perpendicular distance of marker nodes from the virtual plane of the spoke, and ground reaction forces. Both maximum peak amplitudes and RMS measures are considered. Two complementary Orthogonal Arrays are evaluat...

Abstract: Research on welding of materials like steel is still critical and ongoing. An attempt has been made to analyze the effect of process parameters in qualitative manner for welding of AISI1040 steel using processes of Shielded Metal Gas Welding (MIG and TIG). Taguchi method is used to formulate the experimental layout. Exhaustive survey suggest that 5-7 control factors viz., arc voltage, arc current, welding speed, nozzle to work distance and gas pressure predominantly influence weld quality, even plate thickness and backing plate too have their own effect. Design of experiments based on orthogonal array is employed to develop the weldments. The weldments are subjected to testing to find the qualitative properties. The data obtained is checked for adequacy based on ANOVA. The result computed is in form of contribution from each parameter, through which optimal parameters are identified for minimum defects. The data in the present work is collected using ultrasound testing (UT), in which angle beam technique is adopted for the testing of weldments and results are quantified accordingly. The testing of specimens indicated, the presence of defects like LOP, LOF, Blowhole, and Cracks

Abstract: A back light module is a key product for providing sufficient light source for a liquid crystal display (LCD). The light guide plate (LGP), used to increase the light usage rate, is a key component in the back light module. This study researches the microinjection molding process parameters and the quality performance of the LGP. Its purpose was to develop a combining Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) with the Taguchi method. This is to optimize the multiquality performance of the LGP for the injection molding manufacturing process, in which both the LCD and the LGP spontaneously produce the best quality performance for V-cut depth and angle. First, an L18 orthogonal array was planned for the manufacturing parameters that affect the microinjection molding process. These included cooling time, mold temperature, melt temperature, injection speed, injection pressure, packing pressure, packing switching, and packing time. The TOPSIS was used to deal with the single-quality optimization disadvantage of the Taguchi method. Then, the TOPSIS response table was used to obtain the optimized manufacturing parameters combination for a multiresponse process optimization. From the analysis of variance, the significant factors for the quality performance of the LGP could be obtained. In other words, by controlling these factors, it was possible to efficiently control the quality performance of the LGP. Finally, with the five verified experiments, the optimized processing parameters came within a 95% confidence interval. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:54–63, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20181

Abstract: In practice, a product or process possesses multiple quality responses of main interest. The Taguchi method has been found only efficient for optimizing a single quality response. This research, therefore, proposes an approach for solving the multi-response problem in the Taguchi method by integrating the grey relational analysis and super efficiency technique in data envelopment analysis (DEA). The quadratic loss is calculated for each response. The grey relational analysis is used to normalize the quality losses and to obtain grey relational coefficients. Each experiment in the Taguchi's orthogonal array (OA) is then treated as a decision-making unit (DMU) with grey relational coefficients set as the inputs for all DMUs. The super efficiency model is then adopted to estimate the efficiency of each DMU. Finally, the level efficiency, i.e. the average of efficiencies for DMUs at each factor level, is calculated and used to determine the optimal factor levels for the multi-response problem. Four re...

Abstract: In this paper, statistical and regression analysis of kerf width using design of experiments is proposed for WEDM operations. Experimentation was planned as per Taguchi's L'32 (2 1 X 4 4 ) mixed orthogonal array. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, pulse OFF time, wire feed and dielectric flushing pressure. Stainless steel grade 304L was selected as a work material to conduct the experiments. From experimental results, the kerf width was determined for each machining performance criteria. Analysis of variance (ANOVA) technique was used to find out the variables affecting the kerf width. Assumptions of ANOVA were discussed and carefully examined using analysis of residuals. Variation of the kerf width with machining parameters was mathematically modeled by using the regression analysis method. Finally, the developed model was validated with a new set of experimental data and appeared to be satisfactory.

Abstract: Determination of optimal machining parameters is a continuous engineering task whose goals are to reduce the production costs and to achieve the desired product quality. Hence, this paper presents and discusses different optimization methods to determine the optimal values of cutting speed, feed and depth of cut with the purpose of improving the surface roughness obtained in the finish longitudinal turning operation. Two experimental plans, one based on the conventional rotatable central composite design and the other based on the orthogonal arrays and signal-to-noise ratio were carried out on the practical case. By using these plans, different optimization methods, namely analytical, classical mathematical, Taguchi and artificial neural networks were performed and the results of optimal cutting parameters obtained with these methods were compared. Finally, the features, the merits and the limitations of the presented optimization methods were discussed.

Abstract: In this study, an orthogonal immune algorithm (OIA) is proposed for global optimization by incorporating orthogonal initialization, a novel neighborhood orthogonal cloning operator, a static hypermutation operator, and a novel diversity-based selection operator The orthogonal initialization scans the feasible solution space once to locate good points for further exploration in subsequent iterations Meanwhile, each row of the orthogonal array defines a sub-domain The neighborhood orthogonal cloning operator uses orthogonal arrays to scan uniformly the neighborhood around each antibody Then the new algorithm explores each clone by using hypermutation The improved maturated progenies are selectively added to an external population by the diversity-based selection, which retains one and only one external antibody in each sub-domain The OIA is unique in three aspects: First, a new selection method based on orthogonal arrays is provided in order to preserve diversity in the population Second, the orthogonal design with a modified quantization technique is introduced to generate initial population Third, the orthogonal design is introduced into the cloning operator The performance comparisons of OIA with two known immune algorithms and three evolutionary algorithms in optimizing eight benchmark functions and six composition functions indicate that OIA is an effective algorithm for solving global optimization problems

Abstract: This study investigated the multi-response optimization of burnishing process for an optimal parametric combination to yield favorable surface roughness and microhardness using the Grey relational analysis and Taguchi method. Sixteen experimental runs based on an orthogonal array of Taguchi method were performed to derive objective functions to be optimized within experimental domain. The objective functions have been selected in relation of burnishing parameters; burnishing force, number of passes, feed rate and burnishing speed. The Taguchi approach followed by Grey relational analysis was applyed to solve the multi-response optimization problem. The significance of the factors on overall quality characteristics of the burnishing process has also been evaluated quantitatively with the variance method (ANOVA). Optimal results were verified through confirmation experiments. This shows application feasibility of the Grey relation analysis in combination with Taguchi technique for continuous improvement in product quality in manufacturing industry.

Abstract: Multi-fidelity computer experiments are widely used in many engineering and scientific fields. Nested space-filling designs (NSFDs) are suitable for conduct- ing such experiments. Two classes of NSFDs are currently available. One class is based on special orthogonal arrays of strength two, and the other consists of nested Latin hypercube designs; both of them assume all factors are continuous. We pro- pose an approach to constructing new NSFDs based on powerful (t, s)-sequences. The method is simple, easy to implement, and quite general. For continuous fac- tors, this approach produces NSFDs with better space-filling properties than exist- ing ones. Unlike the previous methods, it can also construct NSFDs for categorical and mixed factors. Some illustrative examples are given. Other applications of the constructed designs are briefly discussed.

Abstract: A new class of the almost orthogonal filters is described in this article. These filters are a generalization of the classical orthogonal filters commonly used in the circuit theory, control system theory, signal processing, and process identification. Almost orthogonal filters generate the series of almost orthogonal Legendre functions over the interval (0, ∞). It is well known that all real systems suffer from some imperfections, so the models of these systems should reflect this fact. A new method for obtaining an imperfect system model is proposed. This method uses an almost orthogonal filter, which is based on almost orthogonal functions. Experiments with modular servo drive were performed to validate theoretical results and demonstrate that the method described in the article is suitable for modelling of imperfect systems.

Abstract: This paper proposes an efficient approach for optimizing the multiple quality characteristics (QCHs) in manufacturing applications on the Taguchi method using the super efficiency technique in data envelopment analysis (DEA). Each experiment in Taguchi's orthogonal array (OA) is treated as a decision making unit (DMU) with multiple QCHs set as inputs or outputs. DMU's efficiency is measured then adopted as a performance measure to identify the combination of optimal factor levels. Three real case studies were employed for illustration in which the proposed approach provided the largest total anticipated improvements in multiple QCHs among other techniques such as principal component analysis (PCA) and DEA based ranking (DEAR) approach. Analysis of variance is finally employed to decide significant factor effects and to predict performance.

Abstract: We offer a piece of evidence that the problems of finding the number of mutually unbiased bases (MUB) and mutually orthogonal Latin squares (MOLS) might not be equivalent. We study a particular procedure that has been shown to relate the two problems and generates complete sets of MUB in power-of-prime dimensions and three MUB in dimension six. For these cases, every square from an augmented set of MOLS has a corresponding MUB. We show that this no longer holds for certain composite dimensions.

Abstract: any drilling operation. It causes structural integrity reduction and poor assembly tolerance as well as potential for long-term performance deterioration. As a result, drilling of any material requires dimensional stability and interface quality. In this study, glass fibre reinforced plastic composite is selected as experimental material for investigation of cutting parameters (cutting speed, feed rate and tool geometry) affecting delamination in drilling operation. Moreover, the Taguchi method is used to determine optimal cutting parameters for damage-free drilling material. A plan of experiments, based on L’16 Taguchi design method, is performed drilling with cutting parameters in a GFRP composite. The orthogonal array, signal-tonoise (S/N) ratio and analysis of variance (ANOVA) are employed to investigate the optimal drilling parameters of GFRP composites using four different drills. The experimental results demonstrate that the feed rate is the major parameter among the controllable factors that influence the delamination. Additionally, the optimal combinations of the cutting parameters are determined.

Abstract: Taguchi method was known in many industries as an off-line quality control methodology to improve the performance of products or processes at low cost. Although it was effective at improving quality, the statisticians pointed to inefficiencies in the method for highly nonlinear problems and complexity of the product design, the results were often less than satisfactory. Therefore, recently mathematical model and computer simulation are the other alternatives for robust design. However, Taguchi method and computer simulation have their own advantages and disadvantages. So, this idea motivates the approach of combining both advantages together to promote the more effectiveness of robust design. This paper proposes the approach to apply computer-aided engineering (CAE) with genetic algorithm (GA) and Taguchi method in dynamic robust parameter design. Firstly, we use computer simulation, CAE, to obtain the data instead of conducting whole real experiment. Next, a statistical approach, linear regression is used to model the unknown functions, and then GA, heuristics search approach, is employed to find the appropriate setting of controllable factors on the basis of the quality loss function. The effect of noise factors which is the important philosophy of robust design is also considered by utilizing the outer orthogonal array. The objective is to minimize the average quality loss instead of maximizing SN ratio. In addition, to enhance the capability of the proposed approach, the two-step method is applied to screen out the dispersion factors significantly affecting the quality variation and the adjustment factors significantly affecting the sensitivity of the Taguchi’s dynamic system for the case of changing products or processes’ requirements in the future. This proposed is applied to the example “Foam design of automobile’s dashboard”.

Abstract: This paper examines the influence of cutting parameters on surface roughness of steel workpiece. The experiments have been carried out in accordance with a design of experiments (DOE). Equation for the surface roughness, as a function of cutting parameters, has been obtained by means of regression analysis. To obtain the minimal value of surface roughness, the equation optimizing was performed by using partial derivations and solving system of equations. The Taguchi method, with orthogonal arrays and signal to noise ratio, has been used to analyse impact of various cutting parameters on surface roughness and to find optimal levels of the cutting parameters. The comparison of results obtained by means of the response surface method and the Taguchi method was performed. povr{ine ~eli~nog obratka pri razli~itim parametrima obrade. Pokusi su izvedeni sukladno odabranom planu () /

Abstract: The objective of this paper is to provide a systematic investigation to orthogonal experiment design of backplane. The thermoelectricity reliability is systematically investigated by using mixed orthogonal array L9 (3, 4) based on orthogonal experimental design. The experiment results show that the wire width and wire pitch have a significant impact on the thermoelectricity reliability of the backplane, while the wire thickness has an unobtrusive effect. A finite element model of backplane is established based on a sample structure. The results show that the maximum stress occurred in the copper wire, which connected with FR-4 and the polyimide.

Abstract: A Latin Square (LS) of order n is an arrangement of n symbols in an n × n matrix form so that each symbol occurs in each row and each column exactly once. The total number of Latin Squares LS(n) of order n increases rapidly with n. This helps to design cryptosystems using Latin Squares with a very large key-space. We define encryption and decryption using simple operations on Latin Squares. Different schemes are designed to make the system secure and easy to implement. Use of keyed permutations and construction of large quasigroups ensure that the system is resistant to different practical cryptographic attacks. Computer implementations show the simplicity and power of these schemes for future cryptographic applications in resource-constrained networks or in mobile devices.