Manufacturing Technology Today

A. S. Selvakumar ¹, K. Kalaichelvan ², S. Venkataswamy ³, S. Natarajan ⁴

Affiliations
1 Dept. of Mechanical Engg., B S Abdur Rahman University, Vandalur, Chennai, IN
2 Dept. of Prod. Engg., M. I. T, Anna University, Chennai, IN
3 B S Abdur Rahman University, Vandalur, Chennai, IN
4 Dept. of Mechanical Engg., Anna University, Chennai, IN

Abstract

Hydro forming is a method of deforming sheet metal and tubular materials with the help of pressurized fluid medium using closed dies. In tube hydro forming process an internal fluid medium (inside the tube) serves as the forming medium and the tube is bulged into the desired shape through simultaneous application of axial feed and internal pressure. This paper aims to study the formability characteristic for aluminum tubular materials (A9 6063) for expansion zone geometry by considering various parameters such as axial feed, fluid medium, and semi cone angle of 20°. The formability of tube material was evaluated by varying the process parameters. In the experimental work, the tubular specimen was placed between the two halves of a split die and filled with oil as the forming medium. This tooling was mounted on a hydraulic press. The punch was advanced into the tube to increase the fluid pressure and to provide axial feed of the tube. The optimal expansion zone geometry was identified by various experimental trials, to get flaw free component.

Keywords

Formability, Tube Hydro Forming, Expansion Zone, Pressurised Fluid Medium.

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V. Jai Ganesh ¹, R. Raju ¹, S. Natarajan ², S. Bharathvasan ², P. Chandrasekar ²

Affiliations
1 Dept. of Industrial Engg., Anna University, Chennai, IN
2 Dept. of Production Engg., St. Peters Engg. College, Avadi, Chennai, IN

Abstract

The objective of this study is to select the optimal combination of machining parameters in Wire Electrical Discharge Machining (WEDM) process such that machining performance gets increased. Here the machining performances i.e. responses are measured in terms of Metal Removal rate (MRR), Surface Finish (SF) and Kerf (Cutting width). The most critical factors that affect performance measures are identified as Input peak voltage, Pulse-ON time, Pulse-OFF time, Dielectric fluid pressure, Wire feed, Wire speed and Servovoltage. Eighteen experimental trails based on L₁₈ (2¹ × 3⁷) orthogonal array are conducted and the corresponding responses are measured. Classical methods like factor analysis and desirability index are used for solving this multi-objective problem. Finally the results of two methods are compared and the best combination is chosen.

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V. S. Senthilkumar ¹, S. Natarajan ¹, D. Viswanathan ², D. Babu ¹

Affiliations
1 Department of Mechanical Engineering, College of Engineering, CEG, IN
2 A.C.College of Technology, Anna University, Chennai - 600025, IN

Abstract

Superplastic materials undergoe large amount of plastic deformation. Since large plastic strains can be achieved at relatively low flow stresses, this process leads to considerable industrial interest in superplastic forming of aircraft parts, automobile parts etc, which require relatively high tooling and assembly cost. Therefore, the superplastic forming has become an alternative process to manufacture those components which require fewer stages with minimum wastage. The aim of this paper is to explore the superplastic deformation behavior of the AA7475 aluminum sheet during blow forming in to a circular die by numerical simulation using the Finite element package, C++, and validation with the reported results of experiment. In the theoretical modeling of superplastic forming at every stage of forming, the bulge is assumed to be a part of sphere. From this, a geometric relation is established to predict the thickness distribution, radius of curvature of the dome, height and radius of the bulge at various points of bulging during forming. In the FEM approach, a circular die is modeled and on the top of which AA7475 aluminum alloy blank is fixed rigidly around the die periphery and constant pressure is applied, which is numerically simulated using the FEM package to predict the bulge height as a function of time over the buying profile.

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