Informatics Publishing Limited

Arnab Bose ¹, Saurav Datta ², Asish Bandyopadhuay ³, Dulal Chandra Roy ¹

Affiliations
1 Department of Mechanical Engineering, BESU, Shivpur, Howrah, IN
2 Department of Mechanical Engineering, B. P. Poddar Institute of Management and Technology, Kolkata 700052, IN
3 Department of Mechanical Engineering, Jadavpur University, Kolkata 700032, IN

Abstract

Based on multiple linear regression method, linear mathematical model has been developed to correlate the wire wear ratio and selected process control parameters in the wire electrical discharge machining process. The direct and interactive effects of current, pulse on time and wire feed rate on wire wear ratio have been evaluated quantitatively by using analysis of variance technique and results thus obtained have been represented graphically.

Keywords

Multiple Linear Regression, Analysis of Variance.

Full Text

     

Bharat Chandra Routara ¹, Saumya Darsan Mohanty ², Saurav Datta ², Asish Bandyopadhyay ³, Siba Sankar Mahapatra ²

Affiliations
1 Dept. of Mechanical Engg., KIT University, Bhubaneswar, IN
2 Dept. of Mechanical Engg., National Institute of Technology (NIT), Rourkela, IN
3 Dept. of Mechanical Engg., Jadavpur University, Raja S. C. Mallik Road, Kolkata, IN

Abstract

The present study highlights a multi-objective optimization problem by applying weighted principal component analysis (WPCA) coupled with Taguchi method through a case study in cylindrical grinding of 6061-T4 Aluminum. The study aimed at evaluating the best process environment which could simultaneously satisfy multiple requirements of surface quality. In view of the fact, that traditional Taguchi method cannot solve a multi-objective optimization problem; to overcome this limitation, WPCA has been coupled with Taguchi method. Furthermore to follow the basic assumption of Taguchi method i.e. quality attributes should be uncorrelated or independent; which is not always satisfied in practical situation. To overcome this short coming the study applied Weighted Principal Component analysis (WPCA) to eliminate response correlation and to evaluate independent or uncorrelated quality indices called Principal Components which were aggregated to compute overall quality index denoted as multi-response performance index (MPI). A combined quality loss (CQL) was then estimated which was optimized (minimized) finally. The study combined WPCA and Taguchi method for predicting optimal setting. Optimal result was verified through confirmatory test. This indicates application feasibility of the aforesaid methodology proposed for multi-response optimization and off-line control of correlated multiple surface quality characteristics in cylindrical grinding.

Full Text

     

Saurav Datta ¹, Asish Bandyopadhyay ²

Affiliations
1 Department of Mechanical Engineering, National Institute of Technology, Rourkela, Orissa, IN
2 Department of Mechanical Engineering, Jadavpur University, Raja S. C. Mallik Road, Kolkata, IN

Abstract

Submerged arc welding (SAW) is a useful metal joining process in fabrication industry. The process is characterized by the use of granular flux blanket that covers the molten weld pool during operation. This arrangement avoids atmospheric contamination to the weld bead, facilitates slower cooling rate and, thereby, enhancing mechanical-metallurgical characteristics of the weldment. It is well-known that several process control parameters influence (directly or indirectly i.e. factorial interaction) various quality features of the weldment. Work, to a far extent, has already been done to study the effects of the parameters (as well as their interactions) like voltage, current, electrode stick-out, wire feed rate, traverse speed etc. on bead geometry, weld quality and performance attributes in terms of mechanical-metallurgical-chemical characteristics of the weld produced by submerged arc welding on structural steel. But the search is still being continued and results thereof are being reported which indicate the necessity of acquiring in depth knowledge in this regard. Control of the above parameters, in a more precise manner, can essentially improve weld quality, enhance the possibility of increased deposition rate and economize the overall process. In consideration of the above, the present reporting outlines the trends of research on various aspects of prediction-modeling, simulation and optimization of submerged arc weld. The application feasibility including relative merits as well as demerits of various modeling-optimization methodologies proposed and adopted by previous investigators in examining the process behavior of SAW has been illustratively highlighted. It is felt that the information provided in this reporting may definitely give an insight to the young researchers especially to identify the ischolar_main locus of the past research progressed in the said field and, thereby, helping them in selection of proper direction of work towards value added outcome for the benefit of both academic fraternity as well as industry personnel.

Keywords

SAW, Modeling, Simulation, Optimization.

Full Text

     

Saurav Datta ¹, Asish Bandyopadhyay ², Pradip Kumar Pal ²

Affiliations
1 Department of Mechanical Engineering, B. P. Poddar Institute of Management & Technology, 137, VIP Road, Poddar Vihar, Kolkata - 700052, IN
2 Department of Mechanical Engineering, Jadavpur University, Kolkata-700032, IN

Abstract

In the present research work the reconsumption of the slag, generated during conventional submerged arc welding, has been proposed during subsequent runs by incorporating appropriate treatment and mixing it with fresh flux, with certain proportions. Experiments have been carried out by using four different levels of process parameters like welding current, flux basisity index and slag-mix percentage (percentage of slag in the mixture of fresh flux and fused slag) to obtain bead-on-plate weldment on mild steel plates. Parameters associated with bead geometry like bead height, bead width, depth of penetration have been measured for each experimental run. Heat affected zone (HAZ) geometry in terms of HAZ width has also been obtained. Assuming simple geometry of the weld bead and unit length of the job, approximate bead volume has also been calculated. All these data have been efficiently utilized to develop mathematical models for prediction of geometry and quality of weld bead as well as heat affected zone. Quadratic response surface methodology (RSM) has been applied to develop the mathematical models between predictors and responses. Based on multiple linear regressions, the coefficients of the predictors, used in the models, have been determined. Analysis of Variance Method (ANOVA), F- test and Student's t test have checked the significance of the coefficients. Reduced models with significant coefficients have also been developed. Experimental data as well as generated data have been used to represent graphically the direct and interactive effects of process parameters (slag mix% has given special emphasis in this exercise) on selected response variables associated with weld bead and HAZ. Hardness Test has also been carried out to reflect graphically, the influence of using slag-mix in SAW process on mechanical property of the weldment i.e. hardness of weld metal as well as HAZ. Finally it has been concluded that effect of using slag-mix (up to 20%) do not impose any alarming adverse effect on features of bead geometry and HAZ. Therefore, the use of slag-mix, in submerged arc welding can be recommended to apply it in practical cases, which may make the process more economical.

Keywords

SAW, Slag-Mix, HAZ, RSM, ANOVA.

Full Text