Taguchi Robust Design Method Research Articles

Influence of parallel nozzle electroencapsulation parameters on microcapsule properties – A case study using the Taguchi robust design method

The production of microcapsules by electrospraying two immiscible liquids from oppositely charged parallel nozzles and the subsequent microcapsule collection constitute an electroencapsulation process influenced by numerous parameters. The electroencapsulation parameters include the liquid properties, e.g. bulk liquid conductivity K, viscosity η, density ρ, and surface tension γ; the electric field, gravity field, and the electrospraying and collection geometries; and the atmospheric properties. In the present work, NaI-doped glycerol was used as core liquid, with an optional payload of dispersed thermally carbonized porous silicon nanoparticles (PSi). Chloroform with dissolved Eudragit E 100 cationic copolymer and dispersed talc particles as an anti-tacking agent was used as shell liquid. The influence of varying ten electrospraying parameters (liquid flow rates Qi, electrospraying voltages |Ui| and polarity, solid concentrations, and temperature T) within the cone-jet mode regime on the structure and yield of microcapsules produced by parallel nozzle electroencapsulation was investigated simultaneously using the Taguchi robust design method. Of the investigated parameters, the most important were found to be NaI concentration and T, both influencing the core liquid conductivity; and the liquid flow rates. The Taguchi experiment and additional results suggest that optimally, the parameters affecting liquid conductivities should be set for a coarse atomization current balance when using a maximal shell liquid flow rate. Then, the core liquid flow rate can be adjusted for best process efficiency.

Enhanced β-fructofuranosidase biosynthesis by Rhodotorula glutinis using Taguchi robust design method

The aim of this study was to produce β-fructofuranosidase enzyme by Rhodotorula glutinis SO28, using sugar beet (Beta vulgaris) as carbon source due to its high sucrose content and easy availability. β-Fructofuranosidase production was carried out in submerged fermentation. Taguchi orthogonal array (OA) design of experiment (DOE) method was employed for optimization process of β-fructofuranosidase production by R. glutinis SO28. An OA layout of L16 was constructed with five influential factors on β-fructofuranosidase biosynthesis namely, carbon source (sugar beet), initial pH, incubation temperature, agitation speed and incubation time. The average results of β-fructofuranosidase yield obtained from the determined 16 batches were processed with Minitab® 16.2.3 software at “larger is better” as quality character. The results showed that the maximum β-fructofuranosidase activity was obtained as 21.11 ± 0.47 U/mL, which was close to the predicted result (21.78 ± 0.43 U/mL). Consequently, sugar beet can be suggested as an economical substrate for β-fructofuranosidase production. Besides, use of Taguchi DOE enhanced enzyme activity about 3-fold when compared with unoptimized condition.

Processing optimization of Fresnel lenses manufacturing in the injection molding considering birefringence effect

The Taguchi robust design method is used to examine the effects of the processing conditions on the birefringence properties of a Fresnel lens fabricated using a plastic injection molding technique. The Computer Aided Engineering (CAE) simulation results show that the residual stress within the lens is determined (in descending order of influence) by the melt temperature, the filling time, the packing time and the mold temperature. In addition, it is shown that given an appropriate setting of the processing parameters, the average residual stress can be reduced by 75.1%; resulting in a reduction of 74.7% in the average birefringence. In general, the results presented in this study confirm the effectiveness of the integrated Taguchi/CAE approach in optimizing the performance of plastic Fresnel lenses for a variety of focusing applications.

Preparation of epoxy-based insulator and optimization of its thermal property by Taguchi robust design method in double base propellant grain application

Taguchi method (orthogonal array, OA9) was used to design an epoxy insulator by evaluating its glass transition temperature (Tg) for using in a double base (DB) propellant grain. In this design method, three epoxy resins based on diglycidylether bisphenol A (DGEBA), three polyamine curing agents and a DGEBA-based reactive diluent agent were used. The curing process of epoxy resins with polyamines was studied by Fourier transform infrared spectroscopy. The results showed that the curing process was completed at room temperature. The effects of four parameters including resin type, curing agent type, curing agent concentration and diluent quantity were investigated to design a resin formulation with a highest Tg after curing. The obtained results were quantitatively evaluated by the analysis of variance (ANOVA). The results of ANOVA showed that the highest Tg of 86.0 ± 9.0 °C was obtained for the optimum formulation of MANA POX-95 as epoxy resin, H-30 as curing agent and 52 phr H-30. The Tg measured by the experiment was 78.0 ± 0.9 °C. In addition, the single lap shear strength (adhesion strength) of the optimized insulator was measured at 13.66 ± 1.02 MPa. Pull-off test performed on the surface of DB propellant resulted a 1.935 ± 0.003 MPa adhesion strength.

Preparation of High-Purity Ultrafine Copper Powder in Mass-Production by Chemical Reduction Method: Taguchi Robust Design Optimization

The Taguchi robust design method is implemented for the optimization of experimental conditions in the synthesis of high-purity ultrafine copper powder (HUCP) in mass-production by the chemical reduction method. A reducing agent, reaction temperature, reducing agent weight, and a stirring rate are chosen as the major optimization factors and the conversion rate, particle size, and reaction time are chosen as the desired targets. It is established that the reducing agent and the reaction temperature are the most significant factors that affect the desired targets. Among the selected or designed factors, the optimal conditions for producing the HUCP are: NaH2PO2 · H2O as the reducing agent (level 2), temperature 70°C (level 3), a reducing agent weight of 8.14 kg (level 3), and a stirring rate 300 rpm (level 2). The study results for the three desired targets are in agreement with the prediction made by the Taguchi method. Furthermore, the pure (impurity <0.06%) facecentered cubic structure of the HUCP with 1.51 μm average particle size is extensively characterized and determined by inductively coupled plasma–optical emission spectrometer (ICP–OES), laser particle-size analyzer (DLS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. This surfactant-free facility method is suitable for the synthesis of highpurity ultrafine copper powder by mass-production method.

Taguchi Robust Design of a Wind Shear Mitigation Fence to Enhance Wind Turbine Efficiency

This paper proposes an optimal design method, which consists of computational fluid dynamics and Taguchi robust design method, for a wind shear mitigation fence installed at the upstream of a wind turbine to reduce the fatigue load on the blades and to augment the power generation. The fence generates a virtual hill effect, which mitigates wind shear by speedup of the lower part of the atmospheric boundary layer. For the design factors, the fence height, fence inclination angle, separation distance between the fence and wind turbine, wind speed, and turbulence intensity of the upstream wind profile are considered by constructing a L9 Taguchi orthogonal array. For the performance measures, the wind speed-up within a rotor plane of wind turbine and non-uniformity of the wind speed profile were evaluated. The main design factors were the fence height in terms of power generation augmentation and the separation distance in terms of the fatigue load mitigation. In the case of a 5 m fence installation, a 2% increase in wind speed and 42% decrease in non-uniformity was anticipated so that the substitution of a solid fence with a more practical windbreak is likely to be considered.

A Multivariate Loss Function Approach to Robust Design of Systems with Multiple Performance Characteristics

The Taguchi robust design method traditionally deals with single‐characteristic problems. Various methods have been developed for extending the Taguchi single‐characteristic robust design method to the case of multi‐characteristic robust design problems. However, most of those methods have shortcomings in that they do not properly consider the variance–covariance structures among performance characteristics and/or do not preserve the original properties of the Taguchi signal‐to‐noise ratio for single‐characteristic robust design problems. To overcome these shortcomings, this paper develops a multivariate loss function approach to multi‐characteristic robust design problems with an appropriately defined signal‐to‐noise ratio. Its performance is evaluated using simulated examples, and the results indicate that it generally outperforms existing representative methods for correlated as well as uncorrelated experimental data. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Optimization of parameters for the synthesis of Y2Cu2O5 nanoparticles by Taguchi method and comparison of their magnetic and optical properties with their bulk counterpart

Y2Cu2O5 nanoparticles were synthesized by sol–gel combustion method and effects of different factors on the size of nanoparticles were investigated. In order to reduce the experimental stages, Taguchi robust design method was employed. Acid citric:Cu+2 M ratio, pH, sintering temperature and time were chosen as the parameters for optimization. Among these factors the solution pH had the most influence and the others had nearly the same influence on the nanoparticles sizes. Based on the predicted conditions by Taguchi design, the sample with a minimum particle size of 47nm was prepared. The magnetic behavior of Y2Cu2O5 nanoparticles were measured and found that at low fields they are soft ferromagnetic but at high fields they behave paramagnetically. The magnetic behavior of nanoparticles were compared to their bulk counterparts and found that the Mr of the samples was slightly different, but the Hc of the nanoparticles was 76% of the bulk sample. The maximum absorbance peak of UV–vis spectrum showed a blue shift for the smaller particles.

Process parameters optimisation for Si3N4 in chemical-mechanical polishing via Taguchi technique

By applying chemical-mechanical polishing (CMP) technique to high precision processing of rotary curved surface workpieces of silicon nitride (Si3N4) ceramic, a CMP experimental device was established on a numerical control (NC) jig grinder. Using Taguchi robust design method, through signal to noise ratios (S/N ratios) and analysis of variance, the influence of slurry concentration, slurry flow rate and polishing wheel speed on surface roughness was analysed. With the increase of polishing wheel speed, the surface roughness Ra increased. The optimal process parameters of CMP on rotary curved surface workpieces of Si3N4 ceramic were selected: slurry concentration of 20%, polishing wheel speed of 6,000 r/min, and slurry flow rate of 0.6 L/min. The result showed that the descending order of selected process parameters impacting on surface roughness was polishing wheel speed, slurry flow rate and slurry concentration.

A combined minimum quantity lubrication and MWCNT cutting fluid approach for SKD 11 end milling

This study proposes a novel approach of minimum quantity lubrication (MQL) by integrating it with multiwall carbon nanotube (MWCNT) cutting fluid for use in SKD 11 end milling. The superior thermal conductivity of MWCNTs is used to reduce the heat generated by the cutting tool during the cutting process, reduce heat-related tool wear, and extend the tool life and increase surface accuracy. The characterization of MQL with MWCNTs/nanofluids during the end milling of SKD 11 was investigated. The Taguchi robust design method was used to obtain the optimal combinations of the processing parameters, such as cutting speed, feeding speed, angle of ejection, and relative wt% of MWCNTs for improving the cutting effect of the MWCNT/MQL methodology. Experimental comparisons were conducted between the dry cutting, MQL, and optimal MWCNT/MQL lubrication methods under the same parameters. The results showed for MWCNTs/MQL significantly lower cutting force, cutting temperatures, surface roughness, and tool wear than for the other two approaches, thus demonstrating that MWCNTs/MQL aid considerably in extending tool life and improving surface accuracy.

Robust design of using nanofluid/MQL in micro-drilling

The objective of this study is to present a novel nanofluid/minimum quantity lubrication (MQL) technology for a 7075-T6 aluminum alloy micro-drilling. This technology will enhance the life of the tool for the precision machining. Exploration of nanofluid/MQL-related parameters will affect the effectiveness of distance of nozzle, the nanodiamond weight percent concentration, and the MQL air volume process using the Taguchi robust design method. Additionally, using the Taguchi robust process design also yields the best results when compared with the other micro-drilling characteristics of the dry and MQL methods. Experimental results show that the use of nanofluid/MQL (2 wt%) can effectively reduce the micro-drilling force and micro-drilling torque force as well as the micro-drilling tool for micro-drilling burr wear. Furthermore, there is a significant improvement in the quality of its micro-drilling when the temperature of the drilling process can be significantly decreased.

Integrating sequence-dependent group scheduling problem and preventive maintenance in flexible flow shops

This study integrates flexible flow shop group scheduling problem with sequence-dependent setups and preventive maintenance activities in order to minimize the total completion time (makespan). In a group scheduling problem, scheduling of groups and the jobs within each group are determined. As the considered problem is strongly NP-hard, we propose two meta-heuristics based on simulated annealing (SA) and genetic algorithm (GA) to solve it. Matrix solution representation is a key feature of GA-based algorithm that makes possible the representation of groups and the jobs within groups simultaneously. In addition, the SA-based algorithm is equipped with a local search procedure to enhance the quality of its solution. In order to set parameters and better achieve the performances of the algorithms, we exploit Taguchi robust parameter design method. The performance of the proposed algorithms is evaluated on a variety of test problems, namely small- and large-sized problems. Makespan and elapsed central processing unit (CPU, or processing) time to obtain it are considered as two response variables representing effectiveness and efficiency of the algorithms, respectively. The obtained results show that there is statistically significant difference between performances of the proposed algorithms. GA-based algorithm shows better performance on two response variables for both problem sizes (except regarding elapsed CPU time to obtain the best solution for large-sized problems) with a p value of 0 and outperforms SA-based algorithm.

Parametric optimization of NiFe2O4 nanoparticles synthesized by mechanical alloying

Abstract In this study, the Taguchi robust design method is used for optimizing ball milling parameters including milling time, rotation speed and ball to powder weight ratio in the planetary ball milling of nanostructured nickel ferrite powder. In fact, the current work deals with NiFe2O4 nanoparticles mechanochemically synthesized from NiO and Fe2O3 powders. The Taguchi robust design technique of system optimization with the L9 orthogonal array is performed to verify the best experimental levels and contribution percentages (% ρ) of each parameter. Particle size measurement using SEM gives the average particle size value in the range of 59–67 nm. X-ray diffraction using Cu Kα radiation is also carried out to identify the formation of NiFe2O4 single phase. The XRD results suggest that NiFe2O4 with a crystallite size of about 12 nm is present in 30 h activated specimens. Furthermore, based on the results of the Taguchi approach the greatest effect on particle size (42.10 %) is found to be due to rotation speed followed by milling time (37.08 %) while ball to powder weight ratio exhibits the least influence.

Optimization of glucose formation in karanja biomass hydrolysis using Taguchi robust method.

The main objective of the present study is aimed to optimize the process parameters for the production of glucose from karanja seed cake. The Taguchi robust design method with L9 orthogonal array was applied to optimize hydrolysis reaction conditions and maximize sugar yield. Effect of temperature, acid concentration, and acid to cake weight ratio were considered as the main influencing factors which effects the percentage of glucose and amount of glucose formed. The experimental results indicated that acid concentration and liquid to solid ratio had a principal effect on the amount of glucose formed when compared to that of temperature. The maximum glucose formed was 245 g/kg extractive free cake.

Mixed matrix membrane application for olive oil wastewater treatment: Process optimization based on Taguchi design method

Olive oil mill wastewater (OMW) is a concentrated effluent with a high organic load. It has high levels of organic chemical oxygen demand (COD) and phenolic compounds. This study presents a unique process to treat OMW. The process uses ultrafiltration (UF) membranes modified by a functionalized multi wall carbon nano-tube (F-MWCNT). The modified tube has an inner diameter of 15–30 nm and is added to the OMW treatment process to improve performance of the membrane. Tests were done to evaluate the following operating parameters of the UF system; pressure, pH and temperature; also evaluated parameters of permeate flux, flux decline, COD removal and total phenol rejection.The Taguchi robust design method was applied for an optimization evaluation of the experiments. Variance (ANOVA) analysis was used to determine the most significant parameters affecting permeate flux, flux decline, COD removal and total phenols rejection. Results demonstrated coagulation and pH as the most important factors affecting permeate flux of the UF. Moreover, pH and F-MWCNT UF had significant positive effects on flux decline, COD removal and total phenols rejection. Based on the optimum conditions determined by the Taguchi method, evaluations for permeate flux tests; flux decline, COD removal and total phenols rejection were about 21.2 (kg/m2 h), 12.6%, 72.6% and 89.5%, respectively. These results were in good agreement with those predicted by the Taguchi method (i.e.; 22.8 (kg/m2 h), 11.9%, 75.8 and 94.7%, respectively). Mechanical performance of the membrane and its application for high organic wastewater treatment were determined as strong.

다구치 강건설계 방법 : 현황과 과제

During the past several decades, the Taguchi robust design method has been widely used in various fields successfully. On the other hand, some researchers and practitioners have criticized the method with respect to the way of utilizing orthogonal arrays, the signal-to-noise ratio as a performance measure, data analysis methods, etc., and proposed alternative approaches to robust design. This paper introduces the Taguchi method first, evaluates the validity of the criticisms, and discusses advantages and disadvantages of each alternative. Finally, research issues to be addressed for effective robust design are presented.

Optimization of culture condition for growth and phenol degradation by Alcaligenes faecalis JF339228 using Taguchi Methodology

The optimization of five process parameters such as pH, agitation, temperature, inoculum percentage and incubation time were optimized by Taguchi robust design method for obtaining enhanced biomass and phenol degradation by the isolated Alcaligenes faecalis JF339228 from Durgapur steel industry (DSP), India. About 18 experiments were conducted with a different combination of factors and the results obtained in terms of growth of specific bacterial strain and phenol degradation rates were processed in the Qualitek-4 software to study the main effect of individual factors. The main effect, interaction effects and optimal levels of the process factors were determined using signal-to-noise (S/N) ratio. The effect of factors has been studied for bacterial growth and phenol degradation by A. faecalis JF339228. Optimization of the said parameters has been evaluated by Taguchi method and analysed by analysis of variance. Predicted results showed enhanced process performance such as biomass (131.78%) and phenol degradation (130.40%) with pH (7), temperature (37.5°C), agitation (150 rpm), inoculum percentage (6%) and incubation time (72 h). The optimum values of medium composition obtained for biochemical degradation of phenol by A. faecalis JF339228 could be used for phenol degradation using optimized process parameter by Taguchi’s by this microorganism.

Two approaches to multi-criteria optimisation of steel alloys for crankshafts production

The paper presents the application of multi–criteria optimisation to steel alloy composition determination aimed at obtaining improved properties material for crankshafts production. Neural network model of steel mechanical characteristics in dependence on amounts of its alloying elements was used for simulation purpose. Two optimisation approaches were applied to find optimal alloys composition. In the first one, several Pareto optimal solutions were found based on those obtained by simulation numerous compositions in the investigated region of interest. The second one used Taguchi method for robust design. The obtained optimal solutions were compared and decision about further production experiments was taken.

Synergistic effect of iontophoresis and chemical enhancers on transdermal permeation of tolterodine tartrate for the treatment of overactive bladder

The objective of the study was to evaluate the synergistic transdermal permeation effect of chemical enhancers and iontophoresis technique on tolterodine tartrate (TT) transdermal gel and to evaluate its pharmacokinetic properties. Taguchi robust design was used for optimization of formulations. Skin permeation rates were evaluated using the Keshary-chein type diffusion cells in order to optimize the gel formulation. In-vivo studies of the optimized formulation were performed in a rabbit model and histopathology studies of optimized formulation were performed on rats. Transdermal gels were formulated successfully using Taguchi robust design method. The type of penetration enhancer, concentration of penetration enhancer, current density and pulse on/off ratio were chosen as independent variables. Type of penetration enhancer was found to be the significant factor for all the responses. Permeation parameters were evaluated when maximum cumulative amount permeated in 24 hours (Q24) was 145.71 ± 2.00µg/cm² by CIT4 formulation over control (91.89 ± 2.30µg/cm²). Permeation was enhanced by 1.75 fold by CIT4 formulation. Formulation CIT4 containing nerolidol (5%) and iontophoretic variables applied (0.5mA/cm² and pulse on/off ratio 3:1) was optimized. In vivo studies with optimized formulation CIT4 showed increase in AUC and T1/2 when compared to oral suspension in rabbits. The histological studies showed changes in dermis indicating the effect of penetration enhancers and as iontophoresis was continued only for two cycles in periodic fashion so it did not cause any skin damage observed in the slides. Results indicated that iontophoresis in combination with chemical enhancers is an effective method for transdermal administration of TT in the treatment of overactive bladder.

Plastic hinge length of circular reinforced concrete columns

This paper presents a parametric study of the plastic hinge length of circular reinforced concrete columns using a three-dimensional finite element analysis method, and using the Taguchi robust design method to reduce computational cost. Parameters examined include the longitudinal reinforcing ratio, the shear span-to-depth ratio, the axial force ratio and the concrete compressive strength. The study considers longitudinal reinforcement with yield strengths of 414 MPa and 685 MPa, and proposes simplified formulas for the plastic hinge length of circular reinforced concrete columns, showing that increases in plastic hinge length correlate to increases in the axial load, longitudinal reinforcing and shear span-to-depth ratios. As concrete strength increases, the plastic hinge length decreases for the 414 MPa case but increases for the 685 MPa case.