Study on electrical discharge machining for cemented carbide with non-flammable dielectric liquid: Influence of form of oxygen supplied to dielectric liquid on machining

2017 ◽  
Vol 232 (4) ◽  
pp. 568-577 ◽  
Author(s):  
Masahiro Yoshida ◽  
Yuu Ishii ◽  
Takemi Ueda
Keyword(s):  
Hydrogen Peroxide ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Dielectric Liquid ◽  
Cemented Carbide ◽  
Tool Electrode ◽  
Electrode Wear ◽  
Machining Speed ◽  
Machining Characteristics ◽  
Oil Type

One of the problems faced in the finish electrical discharge machining of cemented carbide is the slow machining speed due to frequent abnormal discharges and concentrated discharge. To resolve this problem, in this study, attempts were made to supply oxygen to oil-type non-flammable dielectric liquid used in finish electrical discharge machining. First, the effects of the form of the oxygen when it is supplied to the dielectric liquid were investigated. As a result, it was found that when oxygen is supplied to the machining gap in the microbubble state, machining is not affected at all. When dissolved in the dielectric liquid and supplied, machining speed was seen to improve. Next, machining experiments were conducted, varying the percentage of 35 wt% hydrogen peroxide water mixed with the dielectric liquid to change the amount of oxygen in the dielectric liquid. As a result, the following were clarified. (1) The machining speed was six times faster than normal dielectric liquid when 15 wt% of oxygen was mixed; (2) at this time, the tool electrode wear had decreased to one-fifth that of normal dielectric liquid; (3) the surface roughness obtained was below Ra 1 µm regardless of the mixed percentage of hydrogen peroxide water; and (4) better machining characteristics were obtained when the workpiece was set as the positive electrode.

Machining Characteristics of IN718 by EDM with Cooled Electrode and Vibration of the Workpiece

2020 ◽  
Vol 996 ◽  
pp. 131-136
Author(s):  
Yao Li ◽  
Cheng Cui ◽  
Bengang Lin ◽  
Li Li
Keyword(s):  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Cryogenic Cooling ◽  
Tool Electrode ◽  
Machining Efficiency ◽  
Electrical Erosion ◽  
Machining Characteristics ◽  
Edm Process ◽  
Process Material

Inconel718 has been widely used in various fields for its good performance, but it is difficult to machine with traditional machining methods. Electrical discharge machining is an alternative competitive process to machine Nickel-based alloys by electrical erosion. In order to improve reduce the electrode loss and improve the machining efficiency, the horizontal ultrasonic vibration of the workpiece and the cryogenic cooling of the tool electrode were applied into the EDM process. Material removal efficiency, surface roughness, surface topography, and microhardness have been characterized.

Research of the Basic Physical Regularities of Material Removal in Electrical Discharge Machining of Tool Steel

2017 ◽  
Vol 756 ◽  
pp. 96-106
Author(s):  
Ľuboslav Straka ◽  
Slavomíra Hašová
Keyword(s):  
Tool Steel ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Main Process ◽  
Tool Electrode ◽  
Electrode Wear ◽  
Workpiece Material ◽  
The Individual ◽  
Selection Of

The paper describes the basic physical regularities of material removal in Electrical discharge machining (EDM) of tool steel. One of the parameters, that material removal regularities quite accurately identifies, is the tool wear rate (TWR). This parameter, however, describes only the regularities concerning the tool electrode wear. More complex parameter for assessing regularities of material removal in EDM is thus electrode wear ratio (EWR). This parameter, except the size of the wear of the tool electrode, also describes the size of the workpiece material removal. Research on material removal was carried out on samples made out of tool steel EN X32CrMoV12-28 using Cu-ETP electrode EN CW004A. Aim of this paper was also based on the selection of main process parameters that significantly influence the material removal in EDM to define the individual specifics with regard to minimizing EWR.

Microstructure and Electrode Discharge Machining of TiN/Si3N4 Composites

2005 ◽  
Vol 475-479 ◽  
pp. 1337-1340
Author(s):  
Chien Cheng Liu ◽  
Jow Lay Huang
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Ceramic Composites ◽  
Tool Electrode ◽  
Electrode Wear ◽  
Micro Edm ◽  
Si3n4 Ceramic ◽  
Whole Process ◽  
Electrode Discharge ◽  
Scanning Electron

Conductive TiN/Si3N4 ceramic composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity investigated. A low electrical resistivity of 1.25×10-3Ω.cm was obtained in 40vol%TiN/Si3N4 composite. The whole process of tool electrode wear is evaluated by sinker-EDM. The machined surfaces of TiN/Si3N4 ceramic composites were examined by scanning electron microscopy (SEM) and profilometry to determine the surface finish. Micropores of 700µm in depth and 70µm in diameter were successfully machined in TiN/ Si3N4 composites by the micro-EDM method.

An Experimental Study of the Phenomenon of Surface Alloying by EDM Process Using Inconel Tool Electrode

2013 ◽  
Author(s):  
Sanjeev Kumar
Keyword(s):  
Experimental Study ◽  
Surface Properties ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Plasma Channel ◽  
Machining Process ◽  
Tool Electrode ◽  
Electrode Wear ◽  
Surface Alloying ◽  
Machining Conditions

Electrical Discharge Machining (EDM) has emerged as a very important machining process due to its numerous advantages. It is extensively used by the die and toolmaking industry for the accurate machining of complex internal profiles. Although EDM is essentially a material removal process, it has been used successfully for improving the surface properties of the work materials after machining. As the dissolution of the electrode takes place during the process, some of its constituents may alloy with the machined surface under appropriate machining conditions. Additive powders in the dielectric medium may form part of the plasma channel in the molten state and produce similar alloying effect. The breakdown of the hydrocarbon dielectric under intense heat of the spark contributes carbon to the plasma channel. Sudden heating and quenching in the spark region also alters the surface properties. This paper reports the results of an experimental study into electrical discharge machining of H13 hot die steel with Inconel (an alloy of chromium, nickel and iron) tool electrode under machining conditions favouring high electrode wear. The results show improvement in micro-hardness after machining by as much as 88%. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis of the machined surfaces show transfer of chromium and nickel from the tool electrode. Both these elements form intermetallic compounds as well as solid solution with iron and strengthen it. It was found that percentage of chromium increased from 5.39% to 6.52% and that of nickel increased from 0.19% to 4.87%. The favourable machining conditions for surface alloying were found to be low value of peak current, shorter pulse on-time, longer pulse off-time and negative polarity of the tool electrode.

scholarly journals Electrical Discharge Machining of Al (6351)-5% SiC-10% B4C Hybrid Composite: A Grey Relational Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
S. Suresh Kumar ◽  
M. Uthayakumar ◽  
S. Thirumalai Kumaran ◽  
P. Parameswaran ◽  
E. Mohandas
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Stir Casting ◽  
Electrode Wear ◽  
Relational Approach ◽  
Process Characteristics ◽  
Multiresponse Optimization ◽  
Grey Relational ◽  
Machining Parameter ◽  
Machining Characteristics

The goal of the present experimental work is to optimize the electrical discharge machining (EDM) parameters of aluminum alloy (Al 6351) matrix reinforced with 5 wt.% silicon carbide (SiC) and 10 wt.% boron carbide (B4C) particles fabricated through the stir casting route. Multiresponse optimization was carried out through grey relational analysis (GRA) with an objective to minimize the machining characteristics, namely electrode wear ratio (EWR), surface roughness (SR) and power consumption (PC). The optimal combination of input parameters is identified, which shows the significant enhancement in process characteristics. Contributions of each machining parameter to the responses are calculated using analysis of variance (ANOVA). The result shows that the pulse current contributes more (83.94%) to affecting the combined output responses.

Experimental Research on Technology of Ultrasonic Vibration Aided Electrical Discharge Machining (UEDM) in Gas

2006 ◽  
Vol 315-316 ◽  
pp. 81-84 ◽  
Author(s):  
Qin He Zhang ◽  
Jian Hua Zhang ◽  
Q.B. Zhang ◽  
Shu Peng Su
Keyword(s):  
Ultrasonic Vibration ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Tool Electrode ◽  
Electrode Wear ◽  
Machining Parameters ◽  
Environment Pollution ◽  
Dielectric Fluids

Ultrasonic vibration aided electrical discharge machining (UEDM) in gas is an electrical discharge machining (EDM) technology, in which gases such as air and oxygen are used as dielectrics and ultrasonic vibration is applied. UEDM in gas can avoid environment pollution, the most serious disadvantage of conventional EDM in kerosene-based oil or other dielectric fluids, and it is environmental-friendly. The technology also possesses virtues of wide applications, high machining efficiency and simple tool electrodes and so on. The principle of UEDM in gas is introduced in this paper. Experiments have been carried out to study the effects of machining parameters on material removal rate (MRR), surface roughness of the workpiece and tool electrode wear ratio (TWR), and the experiments results have also been analyzed.

Electrical Discharge Machining Characteristics of ECAP Copper Electrode

2019 ◽  
Vol 969 ◽  
pp. 738-743
Author(s):  
R. Gopal ◽  
K.R. Thangadurai ◽  
K. Thirunavukkarasu
Keyword(s):  
Equal Channel Angular Pressing ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Research Work ◽  
Copper Electrode ◽  
Machining Process ◽  
Electrode Wear ◽  
Angular Pressing ◽  
Machining Characteristics ◽  
Bare Copper

Enormous research work has done on the electrode wear in spark erosion machining such as hybrid electrical discharge machining process, introducing various methods such as ultrasonic vibration in electrode, rotating the electrode, developing new electrode material (alloys and composites) and surface coated electrode etc,. Equal Channel Angular pressing is one such technique which makes tool material harder through grain refinement and ultimately enhances the tool life. The work material is AISI H13. For this research work, two copper electrodes are prepared, out of which one copper electrode has undergone equal channel angular pressing process. The most influencing parameters of spark machining like current, pulse on time and pulses off time are chosen for this study. The experiments are conducted using bare copper electrode and equal channel angular pressed copper electrode based on the box Behnken approach. The observations are analyzed for the machining characteristics in terms of rate of machining, rate of tool erosion and surface coarseness. Finally, it is found that ECAP processed copper electrode has lesser wear rate and better surface finish than bare copper electrode.

Development of Deburring Technology with Whirling EDM - Influence of the Motor Rotational Speed Control Conditions and the Electrical Conditions on the Machining Characteristics

2012 ◽  
Vol 523-524 ◽  
pp. 293-298
Author(s):  
Atsushi Nakayama ◽  
V. Lertphokanon ◽  
Minoru Ota ◽  
K. Egashira ◽  
K. Yamaguchi ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Electrical Discharge ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
Speed Control ◽  
Tool Electrode ◽  
Feedback Circuit ◽  
Rotational Speed Control ◽  
The Relationship ◽  
Machining Characteristics

The authors developed Whirling Electrical Discharge Machining (Whirling EDM) [1] with the feedback circuit to control gap distance between tool electrode and workpiece. It was found that the probability of discharge was increased by feedback circuit [2]. However, the motor rotational speed control conditions were not optimized and the machining characteristics were not clarified. In this paper, the rotational behavior of tool electrode in Whirling EDM was observed by high-speed camera, and it was considered that the influence of motor rotational speed control conditions on machining characteristics and the relationship between electrical conditions and machining characteristics. As a result, the discharge probability was able to be increased by decreasing range of motor rotational speed in feedback circuit. In addition, the machining characteristics of Whirling EDM which are influenced by electrical conditions were clarified.

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