Taguchi Robust Design Method Research Articles

Analysis of compressive strength and subsidence of a vertebral body cage with Taguchi methods

A titanium mesh cage (TMC) might develop subsidence and cause local kyphotic deformity of the spine. For prevention of this complication, this study was designed to find the most appropriate spike design for a vertebral body cage (VBC). In order to investigate the subsidence of a VBC, three‐dimensional finite element models of the L5 spinal model with a nonlinear contact analysis have been developed. Then, the Taguchi robust design method was used to evaluate spike designs. Finally, the mechanical experiment was developed to obtain the compressive strength of the VBC. For the results of the FEM‐based Taguchi method, the spike row, the spike obliquity, and the spike height were especially important factors for preventing the subsidence. The optimum combinations were pyramidal spike type, a spike height of 2 mm, a spike diameter of 1.4 mm, an oblique geometry, 11 rows per 28 mm, and an inner diameter of 10 mm. For the results of the experiment, the good relationship between finite element simulation and mechanical testing was found with a correlation coefficient of 0.847. The FEM‐based Taguchi method could decrease the effort and time for analyzing the spike factors of the VBC and the mechanical tests might provide the useful evidence to prove the applicability of the finite element models.

Optimisation of process conditions in powder injection moulding of microsystem components using robust design method Part 2 – Secondary design parameters

Powder injection moulding (PIM) is a proper fabrication method for microsystem technology components. This paper studies the process control of PIM to create thin walled, high aspect ratio geometries, which can be easily found in microtechnology based electro chemical, mechanical and biological systems (MECS). The powder used in this study is gas atomised 316L stainless steel with a median particle size of 10 μm. The effects of reducing the thickness of high aspect ratio geometries on the secondary design parameters including the maximum wall shear stress, cooling time and standard deviations of the melt front velocity and areas are studied. The study shows process parameters including fill time, feedstock injection temperature, mould wall temperature and switchover position can be optimised using the Taguchi robust design method.

Optimization of lipase-catalyzed synthesis of xylitol ester by Taguchi robust design method

Enzymatic synthesis of xylitol fatty acid ester was performed in hexane using Novozym 435 (immobilized Candida antarctica lipase on macroporous resin). Taguchi method based on three levels, six variables L 27 orthogonal array robust design was implemented to optimize experimental conditions. The effects of reaction parameters including reaction time (7–24 h), enzyme amount (0.05–0.3 g), temperature (30–60 °C), amount of molecular sieve (1–4 g), substrate molar ratio (0.3–1) and xylitol concentration (0.005–0.015 g/ml) on the percentage yield of sugar ester were investigated. The optimum conditions derived via Taguchi method were: reaction time 7 h, temperature 60 °C, amount of enzyme 0.12 g, amount of molecular sieve 2.5 g, substrate molar ratio 1 and xylitol concentration 0.015 g/ml. The actual experimental yield was 96.10% under optimum condition, which compared well to the maximum predicted value of 96.27%.

Optimizing the ignition behavior of microwave-combustion synthesized Al 2O 3/TiC composite using Taguchi robust design method

The main goal of the current study is to clarify the role of milling time, extra aluminum, porosity and microwave energy on ignition behavior of combustion synthesized Al 2O 3/TiC composite. In fact the present work deals with the microwave-combustion synthesis of Al 2O 3/TiC composite from Al, C and TiO 2 materials using microwave heating. Taguchi robust design method of system optimization with L 9 orthogonal array was used to determine the best level and the percent of contribution (% ρ) of each factor. In order to confirm the formation of Al 2O 3 and TiC phases, the samples were analyzed by X-ray diffraction using Cu Kα radiation. The results showed that both Al 2O 3 and TiC are present in all samples. The crystallite sizes of produced TiC and Al 2O 3 are about 49–87 and 63–208 nm respectively. Also the Taguchi approach proved that the milling time had the most influence on the ignition time (72.87%) and the stress stood in second place (23.55%). The power of microwave had the least influence on the ignition time. While the extra aluminum had the most influence on the combustion temperature (55.08%) and the stress stood in second place (25.92%).

An efficient heuristic versus a robust hybrid meta-heuristic for general framework of serial–parallel redundancy problem

We present a heuristic approach to solve a general framework of serial–parallel redundancy problem where the reliability of the system is maximized subject to some general linear constraints. The complexity of the redundancy problem is generally considered to be NP-Hard and the optimal solution is not normally available. Therefore, to evaluate the performance of the proposed method, a hybrid genetic algorithm is also implemented whose parameters are calibrated via Taguchi's robust design method. Then, various test problems are solved and the computational results indicate that the proposed heuristic approach could provide us some promising reliabilities, which are fairly close to optimal solutions in a reasonable amount of time.

Engineering Design, 4th edition

Engineering Design, 4th edition

A study on the effect of synthesis parameters on the size of nickel particles in sol–gel derived Ni–SiO2–Al2O3 nanocomposites

The present work deals with the synthesis of Ni–SiO2–Al2O3 nanocomposites fabricated by embedding nickel oxide particles, obtained from hexahydrated nickel nitrate [Ni(NO3)2 · 6H2O], in matrixes with different molar percents of Silica/Alumina, through sol–gel method based on hydrolysis and condensation of tetraethylorthosilicate (TEOS) and Aluminum Isopropoxide [Al(OC3H7)3] alkoxides. Due to the various factors, e.g., pH, EtOH/TEOS/H2O ratio, Si/Ni ratio etc., influencing the nickel grain size of the nanocomposites, Taguchi robust design method of system optimization was used to determine the percent of contribution (%ρ) of each factor. The nanocomposites were reduced in a flow of hydrogen and nitrogen gas at 700 °C for half an hour. The nickel grain size in the nanocomposites was determined by utilizing Scherrer`s method and XRD patterns. The smallest nickel grain size obtained from the Taguchi orthogonal array was about 24 nm, later confirmed by TEM observations. After optimization of the controlling factors, a nickel grain size of 15.4 nm was obtained. It was found that the SiO2/Al2O3 molar ratio of the matrix had the most influence on the nickel grain size (29.22%) and the Water/TEOS molar ratio stood in second place (21.44%). It was illustrated that the starting temperature of the aluminum isopropoxide had the least influence on the nickel grain size.

Analytical approach to robust design of nonlinear mechanical systems

The robustness of mechanical systems is influenced by various factors. Their effects must be understood for designing robust systems. This paper proposes a model for describing the relationships among functional requirements, structural characteristics, design parameters and uncontrollable variables of nonlinear systems. With this model, the sensitivity of systems was analyzed to formulate a system sensitivity index and robust sensitivity matrix to determine the importance of the factors in relation to the robustness of systems. Based on the robust design principle, an optimization model was developed. Combining this optimization model and the Taguchi method for robust design, an analysis was carried out to reveal the characteristics of the systems. For a nonlinear mechanical system, relationships among structural characteristics of the system, design parameters, and uncontrollable variables can be formulated as a mathematical function. The characteristics of the system determine how design parameters affect the functional requirements of the system. Consequently, they affect the distribution of system performance functions. Nonlinearity of the system can facilitate the selection of design parameters to achieve the required functional requirements.

Fabrication of NiO/SiO 2 nanocomposites using sol–gel method and optimization of gelation time using Taguchi robust design method

The present work deals with the synthesis of NiO/SiO 2 nanocomposites fabricated by embedding nickel oxide particles, obtained from hexahydrated nickel nitrate (Ni(NO 3) 2·6H 2O), in a silica matrix, through sol–gel method based on hydrolysis and condensation of tetraethyl orthosilicate (TEOS) alkoxide. Due to the various factors, e.g. pH, EtOH/TEOS/H 2O ratio, Si/Ni ratio, etc., influencing the gelation time of the solutions, Taguchi robust design method of system optimization was used to determine the percent of contribution (% ρ) of each factor. It was found that the pH of the solutions had the most influence on the gelation time (68.76%) and the Si/Ni atomic ratio stood in second place (12.95%). It was illustrated that the molar ratio of EtOH/TEOS had the least influence on the gelation time.

Optimization of parameters for the fabrication of gelatin nanoparticles by the Taguchi robust design method

The Taguchi method is a statistical approach to overcome the limitation of the factorial and fractional factorial experiments by simplifying and standardizing the fractional factorial design. The objective of this study was to optimize the fabrication of gelatin nanoparticles by applying the Taguchi design method. Gelatin nanoparticles have been extensively studied in our previous works as an appropriate carrier for drug delivery, since they are biodegradable, non-toxic, are not usually contaminated with pyrogens and possess relatively low antigenicity. Taguchi method with L16 orthogonal array robust design was implemented to optimize experimental conditions of the purpose. Four key process parameters – temperature, gelatin concentration, agitation speed and the amount of acetone – were considered for the optimization of gelatin nanoparticles. As a result of Taguchi analysis in this study, temperature and amount of acetone were the most influencing parameters of the particle size. For characterizing the nanoparticle sample, atomic force microscope and scanning electron microscope were employed. In this study, a minimum size of gelatin nanoparticles was obtained at 50 °C temperature, 45 mg/ml gelatin concentration, 80 ml acetone and 700 rpm agitation speed. The nanoparticle size at the determined condition was less than 174 nm.

Parametric study on the interface pullout strength of the vertebral body replacement cage using FEM-based Taguchi methods

Improper design of vertebral body cages may seriously affect the interface strength and cause the lose of fixation for a vertebral body replacement. This research used a FEM-based Taguchi method to investigate the effects of various factors to find the robust design of the body cage. Three-dimensional finite element models with a nonlinear contact analysis have been developed to simulate the pullout strength of the body cage. Then, the Taguchi robust design method was used to evaluate the spike design. In a situation without bone fusion, the spike row, the spike oblique, and the spike height were especially important factors. The optimum combination has been found to be the pyramidal spike type, a spike height of 2 mm, a spike diameter of 2.2 mm, an oblique geometry, 11 rows per 28 mm, and an inner diameter of 10 mm. In a situation with bone fusion, the spike row, the spike height, and the inner diameter were the most significant factors. Here, the optimum combination has been found to be the conical spike type, a spike height of 2 mm, a spike diameter of 2.2 mm, an oblique geometry, 11 rows per 28 mm, and an inner diameter of 20 mm. The finite element analyses could be used to predict the interface stiffness of the body cages. The FEM-based Taguchi methods have effectively decreased the time and effort required for evaluating the design variables of implants and have fairly assessed the contribution of each design variable.

Optimization of parameters for the synthesis of zinc oxide nanoparticles by Taguchi robust design method

ZnO nanoparticles were synthesized by modified sol–gel process. Taguchi analysis was used in this study and the molar concentration ratio of [LiOH]/[Zn(Ac) 2] was the most influencing parameter on the particle size and the size distribution. The optimal conditions were determined by using Taguchi robust design method and nano-sized ZnO particles (∼30 nm) were obtained.

Optimization of experimental conditions based on Taguchi robust design for the preparation of nano-sized TiO2 particles by solution combustion method

This investigation was aimed at preparing nanocrystalline TiO2 powder by solution combustion method, and searching the optimum preparing conditions by employing Taguchi robust design method. Taguchi robust design method with L18 orthogonal array was implemented to optimize experimental conditions for preparing nano-sized titania particles. Titanium IV n-butoxide was hydrolyzed to obtain titany1 hydroxide [TiO(OH)2], and titanyl nitrate [TiO(NO3)2] was obtained by reaction of TiO(OH)2 with nitric acid. Finally, the aqueous solution containing titanyl nitrate [TiO(NO3)2] and a fuel, glycine, were mixed and combusted to obtain the nano-sized titania. The optimum conditions obtained by this method are as follows (based on 1 mol of TiO2 per batch): concentration of HPC, 0.053 mg cm−3; mole ratio of Ti:H2O:IPA, 1:4:10; hydrolysis time, one hr; the amounts of HNO3 and glycine are 10 ml and 0.5 g, respectively; nitrated temperature, 298 K and nitrated time, 2 h. TiO2 nanocrystalline (∼15 nm) with high BET surface area (350 m2 g−1) and narrow band gap energy (2.7 eV) were thus obtained.

タグチメソッドによる組み込み温度制御システムのロバストPIDパラメータ設計

This paper proposes a robust PID parameter design scheme using Taguchi's robust design method. This scheme is applied to an embedded PID temperature control system which is affected by outside (room) temperature. The effectiveness of this scheme is verified experimentally with a cooking household appliance.

Application of Taguchi robust design method to SAW mass sensing device

It is essential that measurement systems provide an accurate and robust performance over a wide range of input conditions. This paper adopts Taguchi's signal-to-noise ratio (SNR) analysis to develop a robust design for the Rayleigh surface acoustic wave (SAW) gas sensing device operated in a conventional delay-line configuration. The goal of the present Taguchi design activity is to increase the sensitivity of this sensor while simultaneously reducing its variability. A time- and cost-efficient finite-element analysis method is used to investigate the effects on the sensor's response output of variations in the carbon dioxide (CO2) gas deposited mass. The simulation results for the resonant frequency and wave mode analysis are all shown to be in good agreement with the values predicted theoretically.

On the Use of Data Compression Measures to Analyze Robust Designs

In this paper, we suggest a potential use of data compression measures, such as the Entropy, and the Huffman Coding, to assess the effects of noise factors on the reliability of tested systems. In particular, we extend the Taguchi method for robust design by computing the entropy of the percent contribution values of the noise factors. The new measures are computed already at the parameter-design stage, and together with the traditional S/N ratios enable the specification of a robust design. Assuming that (some of) the noise factors should be naturalized, the entropy of a design reflects the potential efforts that will be required in the tolerance-design stage to reach a more reliable system. Using a small example, we illustrate the contribution of the new measure that might alter the designer decision in comparison with the traditional Taguchi method, and ultimately obtain a system with a lower quality loss. Assuming that the percent contribution values can reflect the probability of a noise factor to trigger a disturbance in the system response, a series of probabilistic algorithms can be applied to the robust design problem. We focus on the Huffman coding algorithm, and show how to implement this algorithm such that the designer obtains the minimal expected number of tests in order to find the disturbing noise factor. The entropy measure, in this case, provides the lower bound on the algorithm's performance.

Experimental design in fiber optic sensor development

In this paper, experimental design techniques are utilized to understand sources of variation in an optical fiber sensor design and development project in a university research setting. Application of the Taguchi method of robust design assisted fiber optic sensor development in a cost‐effective and timely manner. According to the analysis, compensation of the source of the variation identified in the experimental design results was achieved on a new design concept of a multiplexed optical fiber sensor. The experimental results and conclusions not only are suitable for this sensor structure, but also are useful for other fiber optic sensors based on the technique of Fabry‐Perot interferometry.

Optimization of experimental conditions based on the Taguchi robust design for the formation of nano-sized silver particles by chemical reduction method

Taguchi robust design method with L 9 orthogonal array was implemented to optimize experimental conditions for the preparation of nano-sized silver particles using chemical reduction method. Particle size and the particle size distribution of silver nano-particles were considered as the properties. Molar concentration ratio of R ([AgNO 3]/[reducing agent (hydrazine)]) value, concentration of dispersant (sodium dodecyle sulfate, SDS), and feed rate of reactant were chosen as main parameters. As a result of Taguchi analysis in this study, the concentration of dispersant was the most influencing parameter on the particle size and the size distribution. The feed rate of reactant had also principal effect on particle size distribution. The optimal conditions were determined by using Taguchi robust design method and nano-sized silver particles (∼8 nm) were synthesized. In addition, by the analyses of X-ray diffraction, high-resolution transmission electron microscopy, and electron diffraction (ED) pattern, the resultant particles were characterized to be pure crystalline silver with a face-centered cubic (fcc) structure.

W1 自動化・統合化・最適化ソフト 「iSIGHT」 の最新の技術動向と事例紹介

This paper shows the latest technology trend and a case of CAO (Computer Aides Optimization) software iSIGHT. Automation, Integration and Optimization are three key functions of iSIGHT. Engineers can make their design process great effective using these three functions. Robust optimal design is also a key function of iSIGHT. It has reliability optimization method, Taguchi robust design method and DFSS (Design For Six Sigma). DFSS minimizes a mean value and a sigma (standard deviation) of an objective function satisfying constraints that aren't violated even if they range in specified sigma level. Multi objective optimization function is reinforced at the latest iSIGHT. NCGA and NSGA-II that are based on genetic algorithm and STA (Satisfied Trade-off Analysis) are involved into iSIGHT.

Design of reconfigurable composite microsystems based on hardware/software codesign principles

Composite microsystems that integrate mechanical and fluidic components with electronics are emerging as the next generation of system-on-a-chip. Custom microsystems are expensive, inflexible, and unsuitable for high-volume production. The authors address this problem by leveraging hardware/software codesign principles to design reconfigurable composite microsystems. They partition the system design parameters into nonreconfigurable and reconfigurable categories. In this way, operational flexibility is enhanced and the microsystems are designed for a wider range of application. In addition, the Taguchi robust design method is used to make the system robust, and response surface methodologies are used to explore the widest performance range for the system. A case study is presented for a microvalve, which serves as a representative microelectrofluidic device.