Experimental Investigations on Eco-Friendly Helium-Mist Near-Dry Wire-Cut EDM of M2-HSS Material

In this paper, helium-assisted near-dry wire-cut electrical discharge machining (NDWEDM) method molybdenum wire has been used to reduce the environmental impact and to cut M2-HSS material. The pressurized non-reacting helium gas mixed with a small amount of water (Helium-mist) is used as the dielectric fluid to accomplish adequate cooling and flush-out debris. The new experimental setup has been developed to conduct the near-dry WEDM tests using the L9 orthogonal array of the Taguchi technique. The input parameters such as voltage (V), pulse-width (PW), pulse-interval (PI), and flow rate (F) of mixing water and output variables are the material removal rate (MRR) and surface roughness (Ra). It was observed that MRR and Ra are amplified by the rise in voltage and pulse-width, and flow rate conversely, the pulse interval minimizes the responses. The percentage of contribution of pulse width, voltage, pulse interval and flow rate are 24.06%, 32.98%, 12.75% and 30.21% on MRR and 20.94%, 22.22%, 47.86% and 8.97% on Ra respectively. Finally, the confirmation trials have been accomplished to validate the foreseen best parameter sets on optimal responses.

Sustainable Eco-friendly Wire-cut Electrical Discharge Machining: Gas Emission Analysis

Wire-cut electrical discharge machining (WEDM) is the highly essential unconventional electro-thermal machining process to cut the contour profile of hard materials in modern production industries. The various environmental impacting wastes (by evaporating and reacting hydro-carbon dielectric fluid) are produced during the WEDM process and these are harmful to the machine operators. These wastes are minimized by a near-dry WEDM process wherein the pressurized air mixed with a small amount of water is used as a dielectric substance. In this research, influences, and contributions of machining parameters such as air pressure, mixing water flow rate, spark current and pulse width on gas emission concentration (GEC), materials removal rate (MRR), and relative emission rate (RER) of sustainable near-dry WEDM process have been optimized by Taguchi analysis. RER is investigated to analyze the effects of machining factors on gas emission and machining rate combinedly. It was revealed that the maximum air pressure and flow rate of mixing water have significantly been promoting the sustainable near-dry WEDM process.

Experimental Investigation and Multi-Objective Optimization of Cryogenically Cooled Near-Dry Wire-Cut EDM Using TOPSIS Technique

In this research, the mixing of compressed air with the minimum quantity of water is used as a dielectric medium and the cryogenically cooled molybdenum wire is used as a tool in wire-cut electrical discharge machining (WEDM) to encourage the eco-friendly production, called cryogenically cooled near-dry WEDM process. The nitrogen gas-cooled wire tool is utilized to cut the Inconel 718 alloy workpiece to prevent wire breakage and maintain enough electrical conductivity. The preliminary experiments were conducted to compare wet, dry, near-dry, and cryogenically cooled near-dry WEDM processes. It was revealed that cryogenic cooled near-dry WEDM is better performance than dry, near-dry WEDM except for the wet process. The systematic experiments of eco-friendly cryogenically cooled near-dry WEDM have been conducted to analyse the effect of input factors like spark current, pulse-width, pulse-interval, and mixing water flow rate on material removal rate (MRR) and surface roughness (SR) using Box–Behnken method. The fitted models and response surface graphs were developed to analyse the influences of input factors on each response parameter. It was concluded that MRR and SR of cryogenically cooled near-dry WEDM are increased by maximizing spark current, pulse-width, and flow rate, conversely, both responses were decreased by increasing pulse-interval. The technique for order of preference by similarity to ideal solution (TOPSIS) technique has been applied to predict the best combination of input factors for satisfying the optimal values of both responses.

A Scenario on Dry-WEDM and WEDM for Industrial Applications

In present day manufacturing industries playing the major role in the machining of new materials with complex shapes, intricate structure and difficult profiles. The improvement of industries and machines is accountable for product quality and accuracy, which are not satisfied in conventional machining techniques. The WEDM is advanced machining process, they are capable to machining the components which are difficult to machine, whereas Dry-WEDM is another method, it utilizes the gas instead of dielectric liquid, it exhibits lower corrosion, fine finish, decrease dielectrics and environment friendly. Development of WEDM is suitable machining option for meeting the demands of modern tool room application and metal cutting industries. The purpose of the article attempts is to highlights the application, improvement and future scope of Dry-WEDM and WEDM in industrial areas.

Experimental Study on Dry WEDM Finishing

Comparing with conventional WEDM in emulsion, dry finishing of high-speed WEDM (HS-WEDM) has advantages such as higher material removal rate, better surface roughness and straightness. Authors have presented a new procedure as gas-liquid combined multiple cut, in which roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while finishing is in gas. For better understanding the effect of machining parameters on surface roughness and cutting speed in dry finishing, a L25(56) Design was implemented. The analysis of variance shows that the effect of pulse duration on surface roughness is of high significance, and peak current is of significance respectively, and the effect of no load worktable feed on cutting speed is high significant.

Gas-Liquid Combined Multiple Cut for WEDM

This study investigates the dry WEDM in multiple cut. To improve surface quality with high-speed WEDM (HS-WEDM), a new procedure as Gas-liquid Combined Multiple Cut (roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while the finishing is in gas) is presented. Effects of pulse duration, peak current, offset, worktable feed and wire length on roughness and removal rate for dry semi-finishing were studied were studied with L16(45) design, and significant order inflluncing roughness and removal rate were found. Experiment results show that multiple cut with dry WEDM in semi-finishing and finishing can improve surface roughness significantly.

Experimental Studies on Dry WEDM in Improving Surface Quality

This study investigates the dry wire electrical discharge machining (WEDM) in multiple cut. To improve surface quality with high-speed WEDM (HS-WEDM), a new procedure as Gas-liquid Combined Multiple Cut (roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while the finishing is in gas) is presented. Effects of pulse duration, pulse interval, peak current, offset, wire winding speed and wire length on roughness, straightness and removal rate had been studied in dry and wet conditions. Experiment results show that multiple cut with dry WEDM in semi-finishing and finishing can improve surface roughness significantly.

Dry WEDM in Improving HS-WEDMed Surface Quality

This paper studies the surface quality of mould steel with high-speed wire electrical discharge machining (WEDM) method, which is conducted in gas to improve the accuracy of finish cut, and compares the surface quality in atmosphere and in emulsion dielectric. Experiment results showed that WEDM in atmosphere offers advantages such as better surface roughness and higher material removal rate. The relationship about winding speed and worktable feed on WEDMed surface quality in semi-finishing cut and finishing cut had been obtained. Morover, a new attemption was successful in applying dry WEDM in multiple cut to improve surface roughness.