Analysis of high aspect ratio small holes in rapid electrical discharge machining of superalloys using Taguchi and TOPSIS

Abstract

The main aim of this paper is to perform high aspect ratio small holes using rapid electrical discharge machining (rapid-EDM) of superalloys, namely Ti-6Al-4V and Inconel 718 with the tool materials like brass tubes and copper tubes. For employing the above-said materials, the performance characteristics such as material removal rate (MRR), tool wear rate (TWR) and overcut (OC) have been studied. In these investigations, DOE-Taguchi's L9 orthogonal array has been utilized to build an experimental layout with the machining parameters such as current, on-time, off-time and capacitance. From the analysis, it is confirmed that there was a 40% increase in MRR, 282% decrease in TWR and 56% decrease in OC for rapid-EDM of Ti-6Al-4V material using the brass tubes than the copper tubes. Further, it is also validated that there is a 61% increase in MRR, 6% drop of TWR and 33% increase in OC for rapid-EDM of Inconel 718 material using brass tubes than the copper tubes. So, this comparative study has concluded that the machining of Ti-6Al-4V using brass tube has produced a maximum of MRR and minimum of TWR and OC. In Taguchi analysis, the individual effect of machining parameters on MRR, TWR and OC was studied. In addition, optimum combinations of machining parameters for MRR, TWR and OC were also discussed. Furthermore, multi-objective optimization was executed using TOPSIS to find good combination of machining parameters.

Experimental study on drilling micro-hole through micro-EDM and optimization of multiple performance characteristics

“…Micro-hole is a well-known feature and requires much attention in a variety of applications to enhance the functional capabilities of the micro-devices [1][2][3][4]. Micro-hole has wide application in numerous areas, for instance, as a probe card for testing semiconductor devices, as shadow mask containing arrays of micro-hole in circular or rectangular shape used in cathode-ray tube (CRT) display, as pentacene thin-film transistors [5,6] and many other applications such as in injection nozzles of the diesel fuel, drug delivery orifices, cooling channels of the turbine blades, spinnerets holes and inkjet printer nozzles [7,8].…”

Experimental investigation of the electrochemical micromachining process of Ti-6Al-4V titanium alloy under the influence of magnetic field

“…The most common of them are ELEC-TRE [27], TOPSIS [28], GREY [29], and VIKOR [30]. TOPSIS, among them, holds its ground as it evaluates with minimal variation, has a lower computational complex and ensures that a common vertices plane is obtained, which postulates a close to ideal solution and negates the far from ideal solution [31]. The methodology of the decision-making in TOPSIS method is highlighted in Figure 4 [32].…”

“…This clearly indicates that no outward stress is affecting the machined material, even though environment of machining has been enhanced. A slight surge in the compressive residual factor will increase the passivation potential of titanium alloy, and would result in higher resistance to corrosion resistance [31], which is the inherent property of titanium alloy.…”

Experimental Investigation of Dry and Cryogenic Friction Stir Welding of AA7075 Aluminium Alloy

“…Conditions. For performing friction stir welding of AA 7075 aluminium alloys in the dry and cryogenic environment, orthogonal (L 27 ) array is availed [5,15,19,[21][22][23][24][25] after running an in-depth preliminary testing before finalizing on the working range for the input factors. e parameters taken in consideration are microhardness and tensile strength in correlation to tool pin profile, pipe rotation speed, welding speed, and axial force applied on the parent material.…”