Taguchi Philosophy of Engineering Quality

Most technology development engineers use traditional reliability engineering methods to calibrate the objective functions of their new systems to meet various marketing requirements. Quality is related to products and services to customer satisfaction. Cost reduction and quality improvement is vital to business. Therefore it is no surprise that both consumers and management are so obsessed with the term quality that a separate branch of quality engineering has been developed. Quite a few glorified terminologies have cropped up such as total quality management (TQM), Quality Function Development (QFD), ISO9000, Continuous quality improvement or KAIZEN, and more popularly six sigma design. These are management-oriented and rather incomprehensible to an average engineer. In contrast, Taguchi methods are easier to comprehend and adopt. They are also based on some common sense ideas. The management's interest was evoked owing to the claimed economic consequences of Taguchi methods of reduced cost with improved quality and consequent consumer satisfaction.

Application of Fuzzy Topsis and Taguchi Methods for Optimization Problems With Disruptive Risk

Ranking and choosing research projects and analyzing experiments are usually difficult and complex responsibilities for professional research councils at universities and research centers. Its complexity stems from having more than one variable in each project, and the participation of many decision-makers in the ranking process and selection of research projects based on many variables. The fuzzy set theory provides the required flexibility to show the uncertainty about the lack of knowledge, and also it can manage the uncertainty in the real world that the values of criteria are not defined properly. For this purpose, in the environment where the criteria of research projects are vaguely defined, the ranking methods such as Taguchi, which can reduce the number of experiments and making process more efficient, can be used for quality design in designing and processing product. In this work, first of all, the authors review fuzzy TOPSIS technique and the Taguchi method as well; then they approach research efficiency and optimization of the level of effective parameters in an experiment.

Effects of drilling parameters on delamination of kenaf-glass fibre reinforced unsaturated polyester composites

Drilling is a secondary material removal and usually carried out to facilitate fastening of parts together. Drilling of composite materials is not usually a problem-free process. Issues related to delamination composite laminates need to be addressed because it introduces the stress concentration point on the composite. This study focussed on the influence of process parameters such as spindle speed, feed rate, type of drill bits and geometry on the extend of delamination experienced by the composite during the drilling process of kenaf-glass fibre-reinforced unsaturated polyester composite, and the delamination measurements were taken under a microscope. Taguchi methods and analysis of variance were employed to find the optimal parameters. From the results, the most significant parameter was the feed rate. The minimum delamination was achieved when the feed rate was 0.05 mm/rev and spindle speed was 700r/min using both types of drill bits. The quality of the drill hole using the twist drill bit has been proven to be better than the brad drill bit.

VARIABLE DETERMINED FOR OPTIMIZATION OF ALTERNATING ENERGY ON THE LOAD BY THE ADAPTIVE TAGUCHI METHOD

It is important to find the optimum point in terms of energy quality in the studies for electrical energy conversions with the converter and inverter circuits. In such studies, it has been tried to find the optimum operating point by using control systems such as PID and Fuzzy Logic in closed-loop controls. When a large number of variables are involved in finding the optimum point, closed-loop control methods such as these may be insufficient to find the optimum point. Therefore, in this study, the Adaptive Taguchi Method (ATM) with the maximum-minimum value is used for the estimation of variables providing the optimum point for energy quality by using it in a multilevel inverter with a double dc-dc converter. While in traditional Taguchi Methods, dependent variables predict the results by revealing their effects on independent variables, in ATM, besides the effects of the independent variables, the effects of different dependent variables on each other are also estimated. First, the system to which the ATM will be applied is introduced. Then, the principles of applying the ATM are explained. In the known Taguchi method, variable values to be found with 34 = 81 trials, variables are estimated with 27 trials, while the values of two different dependent variables in the system can be found with 54 trials instead of 2x34 = 2x81 trials. The resulting values to be estimated with the proposed ATM method are estimated with 27 trials instead of 2x81 or 54 trials. Finally, the observation results to be used for estimation are analyzed and evaluated. By trying the prediction results, it is seen that the proposed system is quite effective because the estimated result value that is %3.71 in the experiments gives a lesser distortion value than the values used for prediction.

Use of Taguchi Methods for Hierarchy of Influence Factors in the Application of Carbonitration in a Fluidized Bed Steel for 41Cr4 Steel

The work is based on carbonitriding in a fluidized layer with methane and ammonia gas applied to 41Cr4 steel samples. To achieve the best possible results, other factors must be taken into account, than those specific to carbonitring. It was necessary to use a partially factorial working procedure due to the increase in the number of factors. An A18 matrix has been used, with 18 lines of experiments in which three levels have been modified for 6 factors. The objective function was fixed at the final hardness after carbonitriding, hardening and tempering. The carbonitriding was performed in fluidized bed with granular solid ground and sorted to 0.1- to 0.16mm, and brought to fluidization with a mixture of methane and ammonia. The hardening has been done directly after carbonitriding in the fluidized bed. The experiments have been performed according to Taguchi Methods and the results indicate an optimal regime and the influence of the factors considered on the hardness after the thermo-chemical treatment and the thermal treatment. Metallographic analysis has been performed on the carbonitrided layer.

Distortion Control for Dissimilar Welding of SS321 to Hastelloy C-276 with CO2 Laser Beam Butt Joints Using Taguchi Methods

The laser beam welding process is a promising technology because of its reliability and ability to automate the process easily. This study aims to analyze distortion for dissimilar laser weld joints. Hastelloy C276 and SS321 plates are joined by using the CO2 Laser beam welding. Welding current, welding speed and shielding gas flow are chosen as process parameters for preparing butt joints. Each of the factors has two levels to control the parameters of the output. Experimentation was conducted with four trails by using an L4 orthogonal array. The quality of the welds and bead geometry are verified through macrostructure examination. The Vernier height gauge was used for the measurement of distortion in the weldments. Lower the better-quality characteristic is chosen for the response. ANOVA studies identified laser power at 81%, the weld speed at 16% parameters is a contribution with a statistical of about 95%. Full penetration was observed for all the experimental trails.

Fabrication of a Silicide Thermoelectric Module Employing Fractional Factorial Design Principles

Thermoelectric modules can be used in waste heat harvesting, sensing, and cooling applications. Here, we report on the fabrication and performance of a four-leg module based on abundant silicide materials. While previously optimized Mg2Si0.3Sn0.675Bi0.025 is used as the n-type leg, we employ a fractional factorial design based on the Taguchi methods mapping out a four-dimensional parameter space among Mnx-εMoεSi1.75−δGeδ higher manganese silicide compositions for the p-type material. The module is assembled using a scalable fabrication process, using a Cu metallization layer and a Pb-based soldering paste. The maximum power output density of 53 μW cm–2 is achieved at a hot-side temperature of 250 °C and a temperature difference of 100 °C. This low thermoelectric output is related to the high contact resistance between the thermoelectric materials and the metallic contacts, underlining the importance of improved metallization schemes for thermoelectric module assembly.

Robust parameter design and economical multi-objective optimization on characterizing rubber for shoe soles

Within Taguchi methods, robust parameter design is a widely used tool for quality improvement in processes and products. The loss function is another quality improvement technique with a focus on cost reduction. Traditional Taguchi methods focus on process improvement or optimization with a unique quality characteristic. Analytical approaches for optimizing processes with multiple quality characteristics have been presented in the literature. In this investigation, a case of analysis for two quality characteristics in rubber for shoe sole is presented. A methodology supported in robust parameter design in combined array is used in order to obtain optimal levels in the vulcanization process. Optimization techniques based on the loss function and the use of restricted nonlinear optimization with genetic algorithms are proposed.