THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Welding Metallurgy of

Melt electrospinning today: An opportune time for an emerging polymer process

Experimental investigations and optimization of surface roughness in turning of en 36 alloy steel using response surface methodology and genetic algorithm

In the last two decades, pressure from various stakeholders has forced many companies to establish environmental and social improvements both in their company and their supply chains. The growing number of journal publications and conference proceedings confirms this change also in academia. The aim of this paper is to analyse and review scientific literature on sustainable supplier management (SSM) with a focus on formal models supporting decision-making in sustainable supplier selection, monitoring and development. For this purpose, a framework on SSM is proposed and a comprehensive content analysis including a criteria analysis is carried out. Beyond this, in total 143 peer-reviewed publications between 1997 and 2014 have been analysed to identify both established and overlooked research fields. Major findings are the rapidly growing interest of this topic in academia in recent years, the predominance of Analytic Hierarchy Process, Analytic Network Process and fuzzy-based approaches, the focus on the f...

Sustainable supplier management – a review of models supporting sustainable supplier selection, monitoring and development

A multi-response optimization problem has been developed in search of an optimal parametric combination to yield favorable bead geometry of submerged arc bead-on-plate weldment. Taguchi’s L25 orthogonal array (OA) design and the concept of signal-to-noise ratio (S/N ratio) have been used to derive objective functions to be optimized within experimental domain. The objective functions have been selected in relation to parameters of bead geometry viz. bead width, bead reinforcement, depth of penetration and depth of HAZ. The Taguchi approach followed by Grey relational analysis has been applied to solve this multi-response optimization problem. The significance of the factors on overall output feature of the weldment has also been evaluated quantitatively by analysis of variance method (ANOVA). Optimal result has been verified through additional experiment. This indicates application feasibility of the Grey-based Taguchi technique for continuous improvement in product quality in manufacturing industry.

Grey-based taguchi method for optimization of bead geometry in submerged arc bead-on-plate welding

Influence of machining parameters, viz., spindle speed, depth of cut and feed rate, on the quality of surface produced in CNC end milling is investigated. In the present study, experiments are conducted for three different workpiece materials to see the effect of workpiece material variation in this respect. Five roughness parameters, viz., centre line average roughness, root mean square roughness, skewness, kurtosis and mean line peak spacing have been considered. The second-order mathematical models, in terms of the machining parameters, have been developed for each of these five roughness parameters prediction using response surface method on the basis of experimental results. The roughness models as well as the significance of the machining parameters have been validated with analysis of variance. It is found that the response surface models for different roughness parameters are specific to workpiece materials. An attempt has also been made to obtain optimum cutting conditions with respect to each of the five roughness parameters considered in the present study with the help of response optimization technique.

Roughness modeling and optimization in CNC end milling using response surface method: effect of workpiece material variation

In the present work, an attempt has been made to solve the correlated multiple criteria optimization problem of submerged arc welding. The target was to search an optimal process environment, capable of producing desired bead geometry parameters of the weldment. Four correlated features of bead geometry: depth of penetration, reinforcement, bead width, and percentage dilution have been selected in the study. The process environment has been assumed consisting of four variables like voltage (OCV), wire feed rate, traverse speed, and electrode stick-out. Multiple correlated responses have been converted into independent quality indices called principal components. Principal component analysis (PCA) has been adapted to covert multiple objectives of the optimization problem into a single objective function. This single objective function has been denoted as composite principal component. Taguchi’s robust optimization technique has been applied to determine the optimal setting, which can maximize the composite principal component. Result of this aforesaid optimization technique has been compared to that of grey-Taguchi technique; another approach which is widely used for solving multicriteria optimization problems. A confirmatory test showed satisfactory result. This concludes application feasibility of PCA-based hybrid Taguchi method for parametric optimization of SA weld.

Application of PCA-based hybrid Taguchi method for correlated multicriteria optimization of submerged arc weld: a case study

In order to build up a bridge between quality and productivity, the present study highlights optimization of CNC end milling process parameters to provide good surface finish as well as high material removal rate (MRR). The surface finish and material removal rate have been identified as quality attributes and are assumed to be directly related to productivity. An attempt has been made to optimize aforesaid quality attributes in a manner that these multi-criterions could be fulfilled simultaneously up to the expected level. This invites a multi-objective optimization problem which has been solved by PCA based Taguchi method. To meet the basic assumption of Taguchi method; in the present work, individual response correlations have been eliminated first by means of Principal Component Analysis (PCA). Correlated responses have been transformed into uncorrelated or independent quality indices called principal components. The principal component, imposing highest accountability proportion, has been treated as single objective function for optimization (multi-response performance index). Finally Taguchi method has been adapted to solve this optimization problem. The aforesaid methodology has been found fruitful in the cases where simultaneous optimization of huge number of responses is required. Keywords: CNC end milling, surface finish, material removal rate (MRR), principal component analysis (PCA), Taguchi
method

https://www.ajol.info/index.php/ijest/article/download/59096/47402

Optimization of CNC end milling process parameters using PCA-based Taguchi method

Laser welding is a potentially useful technique for joining two pieces of similar or dissimilar materials with high precision. In the present work, comparative studies on laser welding of similar metal of AISI 304SS and AISI 316SS have been conducted forming butt joints. A robotic control 600 W pulsed Nd:YAG laser source has been used for welding purpose. The effects of laser power, scanning speed and pulse width on the ultimate tensile strength and weld width have been investigated using the empirical models developed by RSM. The results of ANOVA indicate that the developed models predict the responses adequately within the limits of input parameters. 3-D response surface and contour plots have been developed to find out the combined effects of input parameters on responses. Furthermore, microstructural analysis as well as hardness and tensile behavior of the selected weld of 304SS and 316SS have been carried out to understand the metallurgical and mechanical behavior of the weld. The selection criteria are based on the maximum and minimum strength achieved by the respective weld. It has been observed that the current pulsation, base metal composition and variation in heat input have significant influence on controlling the microstructural constituents (i.e. phase fraction, grain size etc.). The result suggests that the low energy input pulsation generally produce fine grain structure and improved mechanical properties than the high energy input pulsation irrespective of base material composition. However, among the base materials, 304SS depict better microstructural and mechanical properties than the 316SS for a given parametric condition. Finally, desirability function analysis has been applied for multi-objective optimization for maximization of ultimate tensile strength and minimization of weld width simultaneously. Confirmatory tests have been conducted at optimum parametric conditions to validate the optimization techniques.

Asish Bandyopadhyay

Papers

Grey-based taguchi method for optimization of bead geometry in submerged arc bead-on-plate welding

Roughness modeling and optimization in CNC end milling using response surface method: effect of workpiece material variation

Application of PCA-based hybrid Taguchi method for correlated multicriteria optimization of submerged arc weld: a case study

Optimization of CNC end milling process parameters using PCA-based Taguchi method

Comparative study of pulsed Nd:YAG laser welding of AISI 304 and AISI 316 stainless steels