Sachin Maheshwari

Research Developments in Additives Mixed Electrical Discharge Machining (AEDM): A State of Art Review

Electrical discharge machining (EDM) is a well-established modern machining process used to manufacture geometrically complex shapes, process hard materials that are extremely difficult to machine by conventional machining processes. This noncontact machining technique is continuously emerging from a mere tool and dies making process to a microscale machining applications. In recent years, researches have emphasized on increasing machining performance coupled with deliberate surface treatments. Additive mixed electrical discharge machining (AEDM) is a novel innovation for enhancing the capabilities of electrical discharge machining process in this direction. This article presents comprehensive history, mechanism of AEDM process, and reviews research literature in this area. The last part of this article outlines trends for future AEDM research directions.

A Study of Multiobjective Parametric Optimization of Silicon Abrasive Mixed Electrical Discharge Machining of Tool Steel

In this article, a technique for optimization of abrasive mixed electrical discharge machining (AEDM) process with multiple performance characteristics based on the orthogonal array with grey relational analysis has been studied. The process input parameters, i.e., concentration of silicon abrasive powder in dielectric fluid, peak current, pulse-on time, and duty factor, were chosen to study process performance in the form of MRR and surface roughness. The research outcome identifies significant parameters and their effect on process performance on EN-24 tool steel using copper electrode with silicon powder (2 g/l) suspended in kerosene dielectric. The optimum process conditions have been verified by conducting the confirmation experiments.

Technological Advancement in Electrical Discharge Machining with Powder Metallurgy Processed Electrodes: A Review

Electrical discharge machining (EDM) is a well-established machining option for processing hard materials with complex geometrical shapes which are extremely difficult-to-machine by conventional machining processes. These hard materials find applications where lower surface cracks, wear resistance, corrosion resistance, etc. are desirable surface properties. In recent years, research has been carried out to determine the possibility of employing electrode as feed stock material in an effort to produce significant surface alloying. These electrodes are generally produced through powder metallurgy (PM) technique in order to achieve necessary combination of operating characteristics. This paper reports state of art related to the usefulness of PM-processed electrodes in imparting desirable surface properties and modification of the machined surface. The final part of the paper outlines the trends for future EDM research using PM-processed electrodes.

Analysis of Machining Characteristics in Additive Mixed Electric Discharge Machining of Nickel-Based Super Alloy Inconel 718

Additive mixed electric discharge machining (AEDM) is a recent innovation for enhancing the capabilities of electrical discharge machining process. The objective of present research work is to study the influence of operating process input parameters on machining characteristics of nickel-based super alloy (Inconel 718) in aluminium AEDM with copper electrode. The effectiveness of AEDM process on Inconel is evaluated in terms of material removal rate (MRR), surface roughness (SR), and wear ratio (WR) using one variable at a time (OVAT) approach. It is found experimentally that particle concentration and size significantly affect machining efficiency. Aluminium powder (325 mesh size) particles of concentration 6 g/l in AEDM produce maximum machining rate, minimum SR, and 4 g/l produces minimum WR within experimental conditions.

Machining Efficiency Evaluation of Cryogenically Treated Copper Electrode in Additive Mixed EDM

The present experimental investigations have been carried to evaluate machining efficiency with additive powder mixed in dielectric fluid of electrical discharge machining on Inconel 718 with copper and cryogenically treated copper electrodes. Experiments have been conducted to study the effect of input parameters viz. polarity, type of electrode, peak current, pulse on time, duty cycle, gap voltage, retract distance, and concentration of fine graphite powder on machining efficiency. Machining efficiency is evaluated in terms of tool wear rate (TWR) and wear ratio (WR). The optimum factor/level combination of process parameters has been determined by Taguchis approach treating performance measure as single objective response. Analysis of variance (ANOVA) is employed to indicate the level of significance of machining parameters for TWR and WR. The recommended optimal process input conditions have been verified by conducting confirmation experiments and significant improvement in TWR and WR is observed.

Optimisation of electrical discharge machining process with CuW powder metallurgy electrode using grey relation theory

In this paper, an attempt has been made to correlate the usefulness of powder metallurgy (PM) electrodes in electrical discharge machining (EDM). This paper explains the same with the help of experimentation on AISID2 steel in kerosene with CuW (25% Cu and 75% W) PM electrode. An L18 orthogonal array was used to identify the effect of process parameters (viz. electrode material, duty cycle, flushing pressure and current) on the performance characteristics i.e., material removal rate surface roughness and surface hardness. A grey relation grade obtained from the grey relation analysis is used to solve the EDM process with multiple performance characteristics. Experimental results have shown that electric discharge machining process performance can be improved efficiently through this approach. It is found that copper tungsten PM electrode gives better multi-objective performance than conventional copper electrode.

Optimisation of multiperformance characteristics in electric discharge machining of Aluminium Matrix Composites (AMCs) using Taguchi DOE methodology

This paper presents an investigation on the optimisation of process parameters for the Electric Discharge Machining (EDM) of 6061Al/Al2O3p/20p work specimens by employing the Taguchi Design of Experiment (DOE) methodology. One noise factor, aspect ratio (with two levels), and five control factors, viz. pulse current, pulse ON time, duty cycle, gap voltage and tool electrode lift time (three levels each), with an L18 (21 ? 35) fractional factorial design were selected for the present experiment to obtain the optimal settings of factors and study their effects on multiple performance characteristics, namely, Material Removal Rate (MRR), Tool Wear Rate (TWR) and Surface Roughness (SR). The experimental results were analysed by using Signal-to-Noise (S/N) ratios and Analysis of Variance (ANOVA). This analysis recognised the factors on the basis of their significant effect on the performance measures. The derived optimal levels were then used to conduct validation tests to confirm the effectiveness of this approach.

Studies on Mechanical and Morphological Characterization of Developed Jute/Hemp/Flax Reinforced Hybrid Composites for Structural Applications

ABSTRACT In the present study, an attempt has been made to develop and characterize natural fiber-based composites (jute/epoxy, hemp/epoxy, flax/epoxy) and their hybrid composites (jute/hemp/epoxy, hemp/flax/epoxy, and jute/hemp/flax/epoxy) using hand-lay-up technique. Mechanical characterization (tensile, flexural, impact, and hardness test) of the developed composites was performed. The interface between fiber and matrix was examined using scan electron microscopy (SEM). Among (jute/epoxy, hemp/epoxy, flax/epoxy), flax/epoxy composite has shown higher hardness (98 Shore-D) and tensile strength (46.2 MPa) whereas better flexural and impact strength have been shown by hemp/epoxy (85.59 MPa) and jute/epoxy (7.68 kJ/m2) composites respectively. Results showed that hybrid composites observed better mechanical properties. Jute/hemp/flax/epoxy hybrid composite showed the highest tensile strength, modulus and impact strength of 58.59 MPa, 1.88 GPa, and 10.19, kJ/m2, respectively. Jute/hemp/epoxy hybrid composite achieved the maximum flexural strength of 86.6 MPa.

Experimental results and analysis for Electrical Discharge Machining (EDM) of aluminium metal matrix composites with powder-mixed dielectric: Lenth's method

This paper reports the work on EDM with SiC abrasive powder-mixed dielectric, a hybrid process. The machining of 6061Al/Al2O3p/20p work specimens has been carried out with copper electrode. An L18 orthogonal array (OA) was employed for the optimisation of the performance measures such as material removal rate and surface roughness. The effects of seven control factors (three levels each) and a noise factor (two level), and one two-variable interactions on the responses were quantitatively evaluated by the Lenths method. Analysed results indicate that the process effectively improves the MRR and reduces the surface roughness, in comparison with the conventional EDM.

Issues and strategies in composite fabrication via friction stir processing: A review

ABSTRACT Friction stir processing (FSP) is an expeditiously emerging novel technique involving exterior layer modification, which enables one to successfully fabricate surface composites (SCs) as well as bulk composites of the metal matrix. SCs constitute an exclusive class of composites which exhibit improved surface properties while retaining the bulk properties unaltered. During initiative years, FSP was employed in development of SCs of light metal alloys like aluminum. But, nowadays, it has gained a shining role in the field of SC fabrication of various nonferrous alloys like aluminum, magnesium, copper, and even ferrous metals like steel etc. This article reviews the current trends, various issues, and strategies used to enhance the efficiency of the fabrication process of SCs. Factors involved in the process of SC fabrication are discussed and classified with a new approach. Also, variation of microstructural and mechanical characteristics with these factors is reviewed. In addition to a brief presentation on the interaction between various inputs and their effects on properties, a summary of literature on SC fabrication for different metals is tabulated with prominent results. Subsequently, shortfalls and future perspectives of FSP on SC fabrication domain are discussed.