Study the Re-Sticky Phenomenon of Powder Metallurgy Debris in the Electrical Discharge Machining

2009 ◽  
Vol 83-86 ◽  
pp. 968-976
Author(s):  
A Cheng Wang ◽  
Ken Chuan Cheng ◽  
Yan Cherng Lin ◽  
Jeng Shen Huang
Keyword(s):  
Powder Metallurgy ◽  
Melting Point ◽  
Rotational Speed ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Negative Polarity ◽  
Melting Points ◽  
Working Surface ◽  
Adhesive Effect

The debris re-adhering on the machining surface will affect the workpiece precision in EDM; therefore, the main purpose of this research is to study the re-sticky phenomenon of the powder metallurgy (PMM) in EDM. PMM with different melting points from 1450oC to 3410oC were used as EDM materials, the copper and the tungsten were chosen as the electrodes. The polarity in EDM was depended on the pole of the electrode. For observing the re-sticky position of the debris, the electrode was set no rotation or with 200 rpm rotational speed in EDM. The results showed that the melting point of PMM did not exceed 3000oC (PMM did not contain tungsten); the debris of PMM would not re-stick on the working surface no matter what polarity was used in EDM. However, only negative polarity can cause the re-adhesive effect when the melting point of PMM exceeded 3000oC. The debris would re-stick on any machining position when the electrode was not rotated in EDM. However, the debris would adhere on the central of the working area with 200 rpm rotational speed of the electrode.

A Truing Technique of Flattening Diamond Grains for Fabricating Microstructures with Fine Surfaces

2008 ◽  
Vol 389-390 ◽  
pp. 350-355
Author(s):  
Takeshi Harada ◽  
Takuya Semba
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Diamond Tool ◽  
Electrical Discharge Machining ◽  
Polycrystalline Diamond ◽  
Mesh Size ◽  
Diamond Disk ◽  
Working Surface ◽  
Work Material ◽  
Tool Profile

A truing technique that can be used to shape the tip of an electroformed diamond tool into a hemisphere and flatten diamond grains on the tool working surface at the same level as the bond face was developed. A polycrystalline diamond disk whose top surface roughened by electrical discharge machining was partially flattened by grinding was used as a truer. Diamond grains on the tool working surface were successfully flattened along the hemispherical tool profile when the grains mesh size of #1000 was employed. In addition, a grinding test using glasslike carbon as a work material revealed that a surface roughness of less than 50 nm Rz could be obtained in both cases when moving the tool on contour and scanning paths.

Effects of grain size of AISI 304 on the machining performances in micro electrical discharge machining

2016 ◽  
Vol 231 (2) ◽  
pp. 359-366 ◽  
Author(s):  
Qingyu Liu ◽  
Qinhe Zhang ◽  
Min Zhang ◽  
Jianhua Zhang
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Melting Point ◽  
Grain Boundary ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Aisi 304 ◽  
Micro Electrical Discharge Machining

The material removal process of micro electrical discharge machining is based on the instantaneous ultra-high temperature generated by a series of repetitive discharge pulses. Due to the size effects, the polycrystal cannot be considered as continuous and homogeneous material when machining is in micron scale, and the effects of material microstructure should not be neglected. In this article, the thermoelectric characteristics of grain and grain boundary are discussed, and the influence of grain size on the machining performances in micro electrical discharge machining is researched. Two kinds of austenitic stainless steels (AISI 304) which are different in grain size are chosen as the workpieces in experiments. It is verified by both theory models and experimental results that the smaller the grain size, the higher the material removal rate, under the same discharge conditions. Both thermal conductivity and melting point of the grain boundary are lower than those of the grain because of the grain boundary segregation. The effective thermal conductivity and local effective melting point of polycrystalline materials vary with their grain sizes since the grain boundary volume fractions change. As a consequence, the material removal rate of micro electrical discharge machining has direct relationship with grain size of the workpiece.

The Analysis of Processing Factors for Electro-Arc Machining

2013 ◽  
Vol 470 ◽  
pp. 585-588 ◽  
Author(s):  
Min Zhang ◽  
Qin He Zhang ◽  
De Zheng Kong ◽  
Yang Ren
Keyword(s):  
Tool Wear ◽  
Pulse Duration ◽  
Rotational Speed ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Tool Material ◽  
Wear Ratio ◽  
Tool Wear Ratio ◽  
Input Parameters ◽  
Processing Factors

Electro-arc machining is similar with traditional electrical discharge machining (EDM) while the pulse duration of electro-arc machining is longer than that of EDM. The longer discharge was named arcing, and the arcing could lead to high material remove rate (MRR) and low tool wear ratio (TWR). Processing factors including discharge medium, tool polarity, tool material, voltage and rotational speed were chosen as input parameters on MRR and TWR. Taguchis method was used to evaluate their effects. All of the five processing factors had effects on MRR and TWR. The effects and the mechanism are also discussed.

A Study of Liquid Cooling Heat Sink Fabrication and Development in Notebook

2006 ◽  
Vol 505-507 ◽  
pp. 223-228
Author(s):  
A Cheng Wang ◽  
Kuo Zoo Liang ◽  
C.C. Liu ◽  
C.K. Yang
Keyword(s):  
Heat Sink ◽  
Electrical Discharge ◽  
Heat Dissipation ◽  
Electrical Discharge Machining ◽  
Liquid Cooling ◽  
Working Surface ◽  
Erosion Effect ◽  
Long Pulse ◽  
Cutting Path ◽  
Off Time

Liquid cooling heat sink has excellent heat dissipation ability at the personal computer. It can also produce the similar effect at the notebook when the same heat sink is used. However, under the installing space is limited in notebook, the size and weight of heat sink must be limited too. Therefore a novel liquid cooling heat sink was fabricated herein to understand the heat dissipation efficiency in the notebook. Wire electrical discharge machining (WEDM) uses heat erosion effect to remove material and only produces little cutting force on the working surface. Therefore, WEDM has excellent ability to fabricate the straight micro fins (high 1000 μm, width 250 μm, fin gap 400 μm). The WEDM parameters were used to find the precision micro fins in this experiment. The precision micro fins were made when the cutting path offset was 185 μm in WEDM. WEDM would produce over cutting during long pulse duration and it caused oblique micro fins. The appropriate off time in cutting process would promote the WEDM efficiency. However, a liquid cooling heat sink with uniform micro fins and slits was obtained using WEDM.

A Survey on Electrode Materials for Electrical Discharge Machining

2011 ◽  
Vol 697-698 ◽  
pp. 495-499 ◽  
Author(s):  
Li Zhang ◽  
Li Hua Dong ◽  
D.S. Wang ◽  
C.H. Fan ◽  
Y. Zhou
Keyword(s):  
Electrical Discharge ◽  
Electrode Materials ◽  
Electrical Discharge Machining ◽  
Industrial Applications ◽  
High Wear Resistance ◽  
Wear Loss ◽  
Melting Points ◽  
Edm Electrodes ◽  
Materials Used ◽  
Shape Loss

This work screens electrode materials used in EDM and proposes some potential electrodes for future industrial applications. Traditional graphite, W, and Mo EDM electrodes have low TWR due to their high melting points; while, Zn, brass, and Cu often experience too much tool wear. As to some newly developed alloy and composite materials, their machining performances depend on not only their melting points but also their microstructures. Cu-W alloy has high wear resistance but it is susceptible to shape loss due to its internal porosity. By contrast, Cu-graphite, Cu-ZrB2 and Cu-TiB2 composites show good capabilities of removing material with little wear loss and therefore could be promising for future usages.

scholarly journals Fabrication of dental implants with shape memory

2001 ◽  
Vol 82 (6) ◽  
pp. 483-483
Author(s):  
R. G. Khafizov
Keyword(s):  
Powder Metallurgy ◽  
Shape Memory ◽  
Dental Implants ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Optimal Structures ◽  
The Creation

Despite the successes achieved in the field of implantology, the creation of optimal structures for immediate dental implants currently remains the most pressing task. Various methods and technologies are used to create implants: manufacturing of implants by casting, milling, sintering (powder metallurgy), electrical discharge machining, etc. However, the successful functioning of direct implants largely depends on the accuracy of manufacturing, placement and their primary stabilization in the tooth wells.

Optimizing the process parameters for Powder metallurgy electrode in Electrical Discharge Machining

2020 ◽  
Author(s):  
J. Mohammed Azarudeen ◽  
R. Kaja Bantha Navas ◽  
G. Vikas Reddy ◽  
R.S. Gowsik Saran ◽  
S. Prakash ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Process Parameters ◽  
Electrical Discharge ◽  
Electrical Discharge Machining
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