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Ultrasound waves are directly being used in many of the industrial applications including material removal for generating profiles on material surfaces. Trend has been shifted to use ultrasonic sound waves or ultrasonic vibrations as assisting media to enhance process performance. Electric discharge machining is one such industrial application for material removal, where ultrasonic vibrations have been introduced as assisting media for improving process performance. Ultrasonic vibrations were mainly employed in electric discharge machining process for improved debris evacuation from the sparking gap to increase process efficiency. It also resulted in stable and consistent sparking sequences by minimizing adverse arcing phenomenon in electric discharge machining. Since its introduction, technology of ultrasonic assistance in electric discharge machining has gone through considerable changes and penetrated to various variants of the electric discharge machining process mainly die sinking electric discharge machining, wire cut electric discharge machining and micro electric discharge machining.This article presents a research review for applications of ultrasonic vibrations for electric discharge machining process. The review has been carried out in terms of modes of applying ultrasonic vibrations, effect on performance parameters, process modelling and optimization and application for difficult-to-cut advanced materials. Based on the review of present status of the ultrasonic-assisted electric discharge machining, future research needs have been identified to strengthen the capacity and capabilities of the electric discharge machining process. KeywordsUltrasonic vibration, electric discharge machining, ultrasonic vibration-assisted electric discharge machining, die sinking electric discharge machining, wire cut electric discharge machining and micro electric discharge machining Date

Electrical discharge machining has emerged as the most popular non-conventional material removal process due to its novel variants, inherent process capability, and suitability for hybridization with other conventional and non-conventional material removal processes. However, high specific energy consumption, self-sacrificial electrode, hazardous emissions, toxic dielectric waste and sludge generation make this process one of the most unsustainable machining processes. Increased market competitiveness and requirement to comply with ISO 14000 standards demanded to implement sustainable manufacturing practices for short- and long-term business growth. In this article, the authors have reviewed the research work done in three of the sustainability indicators for the electrical discharge machining process, such as environmental impact, personnel health and operational safety. Modes of dielectric supply such as wet, dry and near dry have a paramount influence on the said sustainability indicators. Research works related to each indicator have been reviewed for the three modes of dielectric supply. This review provides a basis for understanding the current status of research activities for electrical discharge machining in the context of sustainability indicators. Future research needs have been discussed to make electrical discharge machining a more sustainable metal removal process.

This work represents a feasibility study for the newly proposed vegetable oil based green dielectric fluids, biodielectric1 (BD1) and biodielectric2 (BD2) for Electric discharge machining (EDM). Comparative analyses for BD1, BD2 and kerosene have been studied to assess the performance in terms of material removal Rate (MRR), electrode wear rate (EWR) and relative wear ratio (RWR) for P20+ cold worked plastic injection mould steel using electrolytic grade copper electrode. Current, Gap voltage, Pulse on time (T on ) andPulse off time (T off ), have been chosen as input parameters and one variable at a time approach has been used for designing experimental plan for investigating feasibility of the newly suggested fluids. The results obtained show that performance of the newly suggested biodielectrics BD1 and BD2 are better than commercially used hydrocarbon based dielectric i.e. Kerosene, for MRR and RWR. ANOVA results indicated that current is the most influencing parameter for MRR and EWR, while T on is the most significant parameter for RWR. Under the influence of current, BD1 and BD2 produced 38% and Downloaded by [New York University] at 00:10 02 August 2015 2165 % improvement in MRR respectively. Moreover, BD1 and BD2 resulted 30% higher and 7% lower RWR, respectively under the influence of T on.

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Critical equipments of process and heavy engineering industries are prone to significant wear due to intense service conditions. Uneven and uncontrolled wear causes significant changes in dimensional and geometrical accuracies of the part surfaces, which adversely affect the parts’ functionality and service life of these parts. Shorter service life of these equipments and subsequent replacement of the same is one of the serious economic concerns. Hardfacing or hardsurfacing is comparatively an advanced metal deposition technology to deposit a hard and complex metal substrate layer on simple and softer base material surface. This process is gaining popularity at commercial level due to its unique capabilities to develop superior wear, corrosion, and impact resistance properties on worn out parts and offer huge economic advantage as substitute to costly replacement. The primarily aim of this study is to present a comprehensive review of the work done on the probable candidates for deposition materials, and summarize the influence of various process parameters on hard-faced surface characteristics. The critical issues like dilution, debonding, and residual stresses have been discussed for multi-layered hardfacing for iron-, nickel-, and cobalt-based hardfacing materials. The secondary aim of this study is to address practical issues such as selection of proper combination of base-substrate material, to understand the response characteristics of ‘plasma transferred arc hardfacing (PTAHF)’ process to minimize the de-bonding, dilution, and residual stresses and finally to improve quality of hardfacing practice.