Deformation characteristics and surface generation modelling of crack-free grinding of GGG single crystals

Nickel-based alloys are attractive materials for industrial applications owing to their good mechanical properties and excellent resistance to corrosion and oxidation, even under extreme conditions. In this paper, the behavior of an INCONEL 600 alloy has been studied using electrical discharge machining (EDM). The response parameters selected are the material removal rate (MRR), the electrode wear (EW), and the surface roughness (SR). All of them have been studied in terms of current intensity supplied by the generator (I), duty cycle (η), pulse time (t
 i
 ), and polarity. To carry out the experiments, design of experiment (DOE) techniques have been used in order to obtain mathematical models to predict the most influential factors by using a small number of experiments. The experimental results confirm that positive polarity leads to higher MRR whereas negative polarity leads to lower Ra values.

Analysis of the influence of EDM parameters on surface finish, material removal rate, and electrode wear of an INCONEL 600 alloy

This paper represents a multivariate hybrid approach, combining Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) and Principal Component Analysis (PCA) to optimize different corr...

Optimization of Machining Condition in WEDM for Titanium Grade 6 Using MOORA Coupled with PCA — A Multivariate Hybrid Approach

The better machining capabilities of abrasive waterjet cutting (AWJC) characterized by the absence of thermal distortion make it highly competitive with other cutting processes employing plasma and lasers. The present report was oriented towards examining the effect of AWJC parameters like abrasive grain size, abrasive flow rate, nozzle–workpiece standoff, water pressure and jet traverse rate on the surface roughness and taper angle of cut produced with ceramic tiles. Taguchi’s L27 orthogonal array was used for conducting the cutting trials, and a combined technique of grey-based response surface methodology (g-RSM) was disclosed for obtaining the optimal level of AWJC parameters. The g-RSM method was supplemented with analysis of variance to identify the vital parameters affecting the quality characteristics. The optimal parameter setting was validated by conducting a confirmation test. The cut surfaces were also examined using field emission scanning electron microscope images, P-profile plots and atomic force microscope images.

Experimental Modelling and Analysis in Abrasive Waterjet Cutting of Ceramic Tiles Using Grey-Based Response Surface Methodology

Experimental study on the cutting force during laser-assisted machining of fused silica based on the Taguchi method and response surface methodology

Inconel 718 is a high-nickel-content superalloy which possesses excellent strength at elevated temperatures and resistance to oxidation and corrosion. This alloy has wide applications in the manufacturing of aircraft engine parts such as turbine disks, blades, combustors and casings, extrusion dies and containers, and hot work tools and dies, but the inherent problems in machining of superalloys with conventional techniques necessitate the use of alternative machining processes. The wire electrical discharge machining (WEDM) process has been recently explored as a good alternative of conventional machining methods, but there is lack of data and suitable models for predicting the performance of WEDM process particularly for Inconel 718. In the present work, empirical modeling of process parameters of the WEDM has been carried out for Inconel 718 using a well-known experimental design approach called response surface methodology. The parameters such as pulse-on time, pulse-off time, peak current, spark gap voltage, wire feed rate, and wire tension have been selected as input variables keeping others constant. The performance has been measured in terms of cutting rate and surface roughness. The models developed are found to be reliable representatives of the experimental results with prediction errors less than ±5 %. The optimized values of cutting rate and surface roughness achieved through multi-response optimization are 2.55 mm/min and 2.54 μm, respectively.

Parametric modeling and optimization for wire electrical discharge machining of Inconel 718 using response surface methodology

Modern aerospace and electronic industries make frequent use of the difficult to machine materials. The micro machining of these materials with conventional edged tool is uneconomical with poor quality of the surface. A relatively new micromachining technology based on magnetic assistance has been used in the recent past to produce quality surface finish on these materials. The magnetic abrasives play an essential role of cutting tools in these processes. However, the magnetic abrasives are not easily available as these are produced by special techniques. This paper highlights major existing technologies that are used to manufacture magnetic abrasives. Main performance characteristics of magnetic abrasives have also been reviewed as regards to micromachining of various surfaces.

Performance of abrasives used in magnetically assisted finishing: a state of the art review

In this paper, a thorough review has been presented on the latest research work carried out for the enhancement of machining performance of one of the most commonly used superalloys that is, Inconel 718. The thermal energy has been frequently utilized for improving machinability characteristics of Inconel 718. The review of available literature indicates that plasma, laser, and electric discharge have been the major sources used for the enhancement of tool life, material removal rate, surface integrity, and reduction of cutting forces during machining of Inconel 718. However, a very few efforts have been made as regards to the use of wire electrical discharge machining and other energies like mechanical, electrochemical, and chemical for machining of this material. Moreover, the reported work on machining of Inconel 718 is largely focused on drilling operations. There is ample scope for research work on various other machining operations using alternative energies to gain more insight into machining of Inconel 718 and other similar superalloys.

Technological Innovations in Machining of Inconel 718: A State of the Art

Electrical Discharge Machining (EDM) is a non conventional machining process capable of accurately machining parts with high hardness and of complex shapes. The sparks produced during the EDM process cause localized melting on the work surface. The formation of recast layer is very common on EDMed surfaces. The recast layer reduces the service life of the die or mould surfaces, especially under fatigue loads. In the present work, Magnetic Abrasive Finishing (MAF) process has been explored as a method to remove the recast layer formed on a EN 31 steel cylindrical specimen machined by EDM. MAF process is one of promising methods capable of removing the material at micro/nano level under gentle mechanical forces. The diamond based sintered magnetic abrasives have been used to machine the EDMed surface. The experimental results indicate that the EDMed surface of EN-31 steel can be successfully finished with diamond sintered magnetic abrasives. On the finished surfaces, no evidence of micro cracks, voids and recast layer has been seen. Moreover, an average improvement in the surface finish up to 80% over the initial surface finish has been obtained. The micro hardness measurement on MAFed surface shows that brittle and hard layer has been removed. SEM photographs indicate the success of MAF for removal of EDMed surface.Copyright © 2015 by ASME

Investigations Into the Removal of EDM Recast Layer With Magnetic Abrasive Machining

With advancement of technology, finely finished surface is one of the major requirements of modern industry. Fine machining with conventional edged tools is uneconomical and sometimes impossible. Magnetic Abrasive Finishing (MAF) is one promising process which is able to remove the material at micro/nano from metallic and non metallic surfaces. The magnetic abrasives play vital role in MAF. Literature reveals different techniques such as sintering, plasma, chemical, etc. for manufacturing of bonded magnetic abrasives. In the present paper, the bonded magnetic abrasives prepared by a new technique called mechanical alloying have been successfully used for the internal finishing of the brass tubes. After rough boring operation, the inner surface of the tubes is finely finished by newly developed magnetic abrasives. Best surface finish obtained by using these magnetic abrasives is of the order of 9 nm.Copyright © 2012 by ASME

Sehijpal Singh Khangura

Papers

Parametric modeling and optimization for wire electrical discharge machining of Inconel 718 using response surface methodology

Performance of abrasives used in magnetically assisted finishing: a state of the art review

Technological Innovations in Machining of Inconel 718: A State of the Art

Investigations Into the Removal of EDM Recast Layer With Magnetic Abrasive Machining

Nano Finishing of Brass Tubes by Using Mechanically Alloyed Magnetic Abrasives