Resource-Efficient Machining of Hard Metals

2014 ◽  
Vol 611-612 ◽  
pp. 708-714 ◽  
Author(s):  
Oliver Kroening ◽  
Mathias Herzig ◽  
Hans Peter Schulze ◽  
Matthias Hackert-Oschätzchen ◽  
Ralf Kühn ◽  
...  
Keyword(s):  
Electrical Discharge Machining ◽  
Discharge Process ◽  
Metal Working ◽  
Short Pulses ◽  
Hard Metals ◽  
Channel Expansion ◽  
Process Energy ◽  
Determining Factor ◽  
Cutting Volume ◽  
Quality Surface

The main requirements of carbide metal working are higher precision and high quality surface which can be fulfilled by electrical discharge machining. This procedure is accompanied with formation of heat affected zones (white layers) during the discharge process negatively. Therefore, the essential post-processing reduces the efficiency of this process and shows the importance of process energy sources (PES) with ultra short discharge in favor of a clearly differentiated cutting volume. By means of simulations of crater geometry and channel expansion the influence of discharge rise time is defined as determining factor for the cut volume and formation of white layers. The technological section presents two different approaches of realizing ultra-short pulses.

Method of Microelectrode with Electrochemical Machining and its Applications

2007 ◽  
Vol 339 ◽  
pp. 360-364 ◽  
Author(s):  
Zhen Long Wang ◽  
Bao Guo Zhu
Keyword(s):  
Surface Property ◽  
Scanning Probe Microscopy ◽  
High Frequency ◽  
Electrical Discharge Machining ◽  
Electrochemical Machining ◽  
Present Situation ◽  
Scanning Probe ◽  
Fabrication Technology ◽  
Tungsten Filament ◽  
Short Pulses

According to the present situation of microelectrode machining, the fabrication technology of microelectrode is put forward by the method of high frequency short pulses in electrochemical machining (ECM). The mechanism of pulses ECM is depicted firstly. Then the system of ECM is designed. After the experiment of technology analyzed, a microelectrode with nice surface is machined successfully. The diameter of the microelectrode is 7μm and the radius of its top is 50nm, which is made of tungsten filament. It could provide the simple electrode for further electrical machining or micro probe for scanning probe microscopy. The surface property, structure, and microhardness of the microelectrode are analyzed. The surface property and the machining capability of the microelectrode are compared with the microelectrode machined by electrical discharge machining (EDM). The superiority of the microelectrode machined by ECM is shown fully. The practicability and reliability are proved by the research of experimentations.

Machinability Comparison of Electrical Discharge Machining of YG15 Hard Metals, 45 Carbon Steel and ZL108 Cast Aluminum Alloy

2010 ◽  
Vol 102-104 ◽  
pp. 446-450 ◽  
Author(s):  
Yan Wang ◽  
Feng Gao
Keyword(s):  
Carbon Steel ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Temperature Fields ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Experimental Conditions ◽  
Carbon Steel Surface ◽  
Hard Metals ◽  
Digital Microscope

A theoretical model of temperature for electrical discharge machining (EDM) is established. Based on finite element method, the distribution temperature fields of ZL108, YG15 and 45 carbon steel during EDM process are simulated with the aid of ANSYS software. The simulation model provides good effects on the surface quality forecast, parameter regulation and optimization in the process of EDM. Under same experimental conditions, the machining efficiencies of EDM ZL108, YG15 and 45 carbon steel are listed. The machining efficiency of EDM ZL108 or 45 carbon steel is much higher than YG15. The observations of YG15, ZL108 and 45 carbon steel surface micro-patterns after EDM are made by VHX-600 3D digital microscope. Form the experimental results, we can explain why ZL108 and 45 carbon steel are tractable metals, while YG15 is difficult-to-cut metal.

Influence of Electrode Cooling on Material Migration among the Electrodes during EDM of Titanium Alloy

2011 ◽  
Vol 264-265 ◽  
pp. 1199-1204 ◽  
Author(s):  
Suleiman Abdulkareem ◽  
Ahsan Ali Khan ◽  
Mohamed Konneh
Keyword(s):  
Liquid Nitrogen ◽  
Electrical Discharge Machining ◽  
Electrically Conductive ◽  
Workpiece Surface ◽  
Hard Metals ◽  
Material Migration ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time ◽  
Dies And Moulds

Electrical discharge machining (EDM) is widely used in the machining of electrically conductive hard metals for the production of dies and moulds. This paper describes an investigation of the effect of electrode cooling on the amount of elements migration from the electrode to the workpiece surface and from the workpiece to the electrode surface. In the present study EDM has been performed with electrodes cooled by liquid nitrogen as well as with electrodes without cooling. Current, pulse-on time, pulse-off time and voltage were taken as the variables during conducting the experiments. The analysis on material migration during EDM was carried out by SEM and EDX. It was observed that EDM with liquid nitrogen reduces material migration and minimizes the surface contamination of both the electrodes.

scholarly journals Influence of Discharge Gap On Material Removal and Melt Pool Movement in EDM Discharge Process

2021 ◽  
Author(s):  
Xiaoming Yue ◽  
Ji Fan ◽  
Qi Li ◽  
Xiaodong Yang ◽  
Zuoke Xu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Material Removal ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
External Pressure ◽  
High Speed Photography ◽  
Discharge Process ◽  
Melt Pool ◽  
Discharge Gap ◽  
Gap Width

Abstract In electrical discharge machining (EDM), gap control is the key to stable processing; the discharge gap plays a significant role in EDM. To determine the influence of the discharge gap on material removal and melt pool movement, which are two fundamental issues in EDM, high-speed photography and molecular dynamics (MD) simulations were used to study the discharge process. Research results demonstrate that the discharge gap has a significant influence on material removal during the discharge process. A smaller gap width produces more and larger removed materials. The influence mechanism of the gap width on material removal is explained as follows. A smaller gap width produces discharge plasma with a smaller diameter and greater heat flux. Discharge with a greater heat flux generates more material removed during the discharge process. In addition, a smaller gap width and greater heat flux produce a stronger interaction of metal vapor jets, generating a stronger shear force acting on the melt pool. The discharge gap also influences the movement of the melt pool and the final topography of the discharge crater through external pressure acting on the melt pool. Smaller gap width produces greater external pressure acting on the melt pool, generating a bowl-shaped melt pool and a discharge crater with a depression in the center and a bulge around the edge. A larger gap width produces less external pressure acting on the melt pool, generating a flat melt pool and a discharge crater with swelling in the center and a depression around the edge.

Optimization of Process Parameters Using Soft Computing Techniques

2017 ◽  
pp. 177-220
Author(s):  
Supriyo Roy ◽  
Kaushik Kumar ◽  
J. Paulo Davim
Keyword(s):  
Soft Computing ◽  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Principal Component ◽  
Optimization Of Process Parameters ◽  
Hard Metals ◽  
Optimal Values ◽  
Grey Relational ◽  
Conventional Machining

Machining of hard metals and alloys using Conventional machining involves increased demand of time, energy and cost. It causes tool wear resulting in loss of quality of the product. Non-conventional machining, on the other hand produces product with minimum time and at desired level of accuracy. In the present study, EN19 steel was machined using CNC Wire Electrical discharge machining with pre-defined process parameters. Material Removal Rate and Surface roughness were considered as responses for this study. The present optimization problem is single and as well as multi-response. Considering the complexities of this present problem, experimental data were generated and the results were analyzed by using Taguchi, Grey Relational Analysis and Weighted Principal Component Analysis under soft computing approach. Responses variances with the variation of process parameters were thoroughly studied and analyzed; also ‘best optimal values' were identified. The result shows an improvement in responses from mean to optimal values of process parameters.

Research on discharge characteristics of working mediums of electric discharge machining

2020 ◽  
Vol 235 (1-2) ◽  
pp. 34-40
Author(s):  
Min Li ◽  
Lanrong Cai ◽  
Junling Zhao
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Base Material ◽  
Deionized Water ◽  
Water Medium ◽  
Discharge Process ◽  
Dry Powder ◽  
Discharge Characteristics ◽  
Mixed Medium ◽  
Tc4 Alloy

Successful surface modification can be obtained by Electrical Discharge Machining (EDM). In this work the discharge characteristics in misted deionized water and near-dry powder-mixed medium was studied systematically, as well as the microstructure and properties of electrical discharge strengthened layers on TC4 alloy. It indicates that the breakdown voltage of EDM in misted deionized water medium has been reduced to about 1/3 than in air medium. In near-dry powder-mixed medium, it is reduced to about 1/9, because the discharge gap is much larger than that of other mediums. In other words, a stable discharge can be obtained by larger discharge gaps and lower pulse energy than traditional EDM surface strengthening method, which leads to more stable discharge process. Experimental researches show that dense and sound combination with matrix like, multiphase hybrid intensification and chrysanthemum petal-like microstructure of strengthened layers can be observed in the near-dry powder-mixed medium. Meanwhile, it is found that the microhardness of the strengthened layer is up to about 1200 HV, which is four times higher than the base material.

Influence of Electrode Cooling on Recast Layers and Micro Crack in EDM of Titanium

2011 ◽  
Vol 264-265 ◽  
pp. 1180-1186 ◽  
Author(s):  
Suleiman Abdulkareem ◽  
Ahsan Ali Khan ◽  
Mohamed Konneh
Keyword(s):  
Electrical Discharge Machining ◽  
Copper Electrode ◽  
Dielectric Fluid ◽  
Machining Parameters ◽  
Manufacturing Method ◽  
Conductive Materials ◽  
Hard Metals ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Edm Process

Electrical discharge machining (EDM) process is a manufacturing method for shaping hard metals and formation of deep and complex shaped hole by spark erosion in electrical conductive materials such as metals, metallic alloys, ceramics etc. EDM process is achieved by a series of recurring electrical discharges between the electrode and workpiece in the presence of dielectric fluid. EDM unique feature of using thermal energy to machine conductive materials irrespective of material hardness has been its major advantage in the manufacture of aerospace, surgical, mould, die, automotive and as well as sport components. The effectiveness of EDM process depends among other factors on the thermal properties of the electrode material. The objective of this study is to study the influence of electrode cooling on recast layers and micro crack in EDM of titanium. The machining parameters investigated in the present study are current intensity (I), pulse on-time (Ton), pulse off-time (Toff) and gap voltage (V), which are of great interest for EDM researchers. The copper electrode is used to EDM titanium workpiece at room temperature and at sub-zero temperature using liquid nitrogen. The influence of cooling of copper electrode on recast layers and micro crack on titanium were investigated using scanning electron microscope (SEM) and has been reported in this study.

Measurement of Polycrystalline Diamond Craters in Electrical Discharge Machining

2014 ◽  
Vol 664 ◽  
pp. 304-309 ◽  
Author(s):  
Bo Hu ◽  
Song Lin Ding ◽  
Christopher Lim ◽  
Milan Brandt ◽  
John Mo
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Polycrystalline Diamond ◽  
Discharge Process ◽  
Grinding Method ◽  
3D Microscopy ◽  
Crater Morphology ◽  
Focus Variation ◽  
The Individual ◽  
Variation Technique

The electrical discharge grinding method is widely used to machine polycrystalline diamond tools because diamond is the hardest material and the traditional abrasive grinding method leads to high tool wear rate. The aim of this study was to find a method to precisely measure the individual diamond crate morphology during the electrical discharge process. A 3D microscopy with the focus-variation technique was chosen to obtain the stereolithography file of the polycrystalline diamond craters. The measurements were shown that the polycrystalline diamond crater morphology is more complex than that of normal tungsten carbide material. This finding can help build more accurate model of polycrystalline crater formation during electrical discharge process.

Combined Atomistic-Continuum Modeling of Nano-EDM Process

2014 ◽  
Vol 887-888 ◽  
pp. 1210-1214 ◽  
Author(s):  
He Li ◽  
Jian Wen Guo ◽  
Wu Yi Ming ◽  
Zhen Zhang
Keyword(s):  
Simulation Model ◽  
Electrical Discharge Machining ◽  
Point Of View ◽  
Machining Process ◽  
Dynamics Simulation ◽  
Discharge Process ◽  
Temperature Model ◽  
Single Discharge ◽  
Edm Process ◽  
Two Temperature

Nano electrical discharge machining (nanoEDM) method is an attractive measure to the manufacturing of parts of nanoscale dimension or precision, and is getting more and more interest of researchers, however, due to the incompleteness of EDM theories, the development of more advanced nanoEDM technology is impeded. In this paper, a hybrid simulation model, namely, combination of the molecular dynamics simulation model and two-temperature model of single discharge process in nanoEDM is constructed to study the machining process of nanoEDM from the thermal point of view.

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