Study of Micro Structural Material Changes after WEDM Based on TEM Lamella Analysis

Wire electrical discharge machining is an unconventional machining technology that is crucial in many industries. The surface quality of the machined parts is carefully monitored, but the condition of the subsurface layer also plays a crucial role, especially in case of defects occurrence such as cracks or burnt cavities. The subsurface layer of individual materials is affected differently due to wire electrical discharge machining. For this reason, this study was carried out focusing on a detailed analysis of transmission electron microscope (TEM) lamella made of Ti-6Al-4V titanium alloy, AlZn6Mg2Cu aluminum alloy, pure molybdenum, Creusabro 4800 steel, and Hardox 400 steel. The attention was first of all paid to the concentration and distribution of individual elements in the recast layer and also in the base material, which was often affected by wire electrical discharge machining. Further, a diffraction analysis was performed for each TEM lamella in the adhesive area and in the base material area. In order to assess the macro-effects on the machined material, the topography analysis of the machined surfaces and the morphology analysis were performed using electron microscopy.

Download Full-text

Surface Quality of Cavities Obtained by EDM Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.223.931 ◽

2011 ◽

Vol 223 ◽

pp. 931-939

Author(s):

Rodrigo Panosso Zeilmann ◽

Gerson Luiz Nicola ◽

Fernando Moreira Bordin ◽

Tiago Vacaro ◽

Mariana Czarnobay Zanotto

Keyword(s):

Surface Quality ◽

Electrical Discharge Machining ◽

Subsurface Layer ◽

Side Wall ◽

Machining Processes ◽

Electrically Conductive ◽

Machined Parts ◽

Edm Process

The electrical discharge machining (EDM) is a process widely used in machining of complex geometries and hardened materials, conditions that often are not met by conventional machining processes. In EDM the electrode reproduces its image or geometry on the part and this image is obtained by chip removing process, which is given by high frequency electrical discharges, causing the melting and vaporization of electrically conductive materials. Due to this mechanism of material removal, the surface is subjected to high thermal loads, which heavily influences the surface quality of obtained parts. For the characterization of these surfaces must be considered the surface topography and the metallurgical changes of the subsurface layer, since both characteristics influence the functionality of the machined parts. In addition, several variables related to the EDM process have influence on the characteristics of the generated surface. This work presents a study of the influence of EDM process on the surface quality of square cavities. It was evaluated different regions of the cavities, such as side wall, bottom and corners. The results showed significant differences between the analyzed regions.

Download Full-text

Analysis of selected effects of the conventional and unconventional machining of titanium alloys

Mechanik ◽

10.17814/mechanik.2019.10.86 ◽

2019 ◽

Vol 92 (10) ◽

pp. 655-657

Author(s):

Paweł Karolczak ◽

Dariusz Poroś ◽

Maciej Kowalski

Keyword(s):

Titanium Alloys ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Alloy Surface ◽

Tool Geometry ◽

Wire Electrical Discharge Machining ◽

3D Geometry ◽

Selected Effects ◽

Unconventional Machining ◽

Brass Wire

In this article, the results of wire WEDM (wire electrical discharge machining) of Ti6Al4V are collated by turning with modified wiper tool geometry. The electrode is CuZn37 brass wire with a diameter of 0.25 mm The analysis of 3D geometry of the Ti6Al4V alloy surface after wiper and WEDM cutting is presented. The possibilities and limitations of wiper and WEDM machining of titanium alloys were indicated.

Download Full-text

Effects of abrasive types on the surface integrity of abrasive-flow-machined surfaces

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405416662080 ◽

2016 ◽

Vol 232 (6) ◽

pp. 1044-1053 ◽

Cited By ~ 10

Author(s):

Kursad Gov ◽

Omer Eyercioglu

Keyword(s):

Surface Roughness ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

White Layer ◽

Machining Process ◽

Wire Electrical Discharge Machining ◽

Abrasive Flow Machining ◽

The Media ◽

Surface Improvement

In this article, the effect of abrasive types on the abrasive flow machining process was investigated. Four groups of abrasive media were prepared with different types of abrasives: SiC, AL2O3, B4C and Garnet. An experimental study was performed on DIN 1.2379 tool steel. The specimens were cut using wire electrical discharge machining and finished with the abrasive flow machining process. The results show that the white layer that formed during wire electrical discharge machining was successfully removed by abrasive flow machining in a few cycles. Although the surface roughness improves with similar trends for all media groups, the results show that the media prepared with B4C and SiC have more surface improvement than the Al2O3 and Garnet ones. The resulting average surface roughness (Ra) values are comparable to the surface quality of those obtained from lapping and super-finishing. The material removal is directly related to the hardness of the abrasive.

Download Full-text

Dry WEDM in Improving LS-WEDMed Surface Quality

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.53-54.387 ◽

2008 ◽

Vol 53-54 ◽

pp. 387-392 ◽

Cited By ~ 4

Author(s):

Tong Wang ◽

Yu Mei Lu ◽

Shu Qiang Xie ◽

Shuang Shuang Hao ◽

H. Zhao

Keyword(s):

Surface Roughness ◽

Surface Quality ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Wire Electrical Discharge Machining ◽

Dry Wedm ◽

Cut Surface ◽

Discharge Gap

Utilizing gas as the dielectric instead of dielectric liquid has enabled the development of dry wire electrical discharge machining (dry WEDM) technology for finishing cut. Experiment results showed that Low-Speed WEDM (LS-WEDM) in gas offers advantages such as better straightness, and shorter discharge gap. This paper studies on influence of different gas dielectrics, wire winding speed and pulse duration on the WEDMed surface quality (discharge gap, straightness, surface roughness, removal rate) in finishing. New attempt of applying dry WEDM as the 4th cut had been proved feasible in improving conventional multiple cut surface quality of LS-WEDM.

Download Full-text

Characteristics of a Schottky Barrier Diode and the SiC Wafers Sliced by Wire Electrical Discharge Machining

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.784 ◽

2014 ◽

Vol 778-780 ◽

pp. 784-787

Author(s):

Hidetaka Miyake ◽

Nobuyuki Tomita ◽

Yoshiyuki Nakaki ◽

Tomoaki Furusho ◽

Atsushi Itokazu ◽

...

Keyword(s):

Schottky Barrier ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Crystal Defects ◽

Wire Electrical Discharge Machining ◽

X Ray ◽

Transmission Electron ◽

Width Of Kerf ◽

First Time ◽

Wafer Surfaces

The multi-wire electrical discharge slicing (multi-wire EDS), which is a brand-new method for fabricating wafers, is expected to considerably reduce the production cost of SiC wafers by decreasing in the width of kerf and kerf loss. We evaluated, for the first time, the influences of a wire electrical discharge machining (WEDM) on the SiC wafers based on experiments using WEDM equipped with a power supply of EDS. Although the analyses by transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) revealed that the WEDM influenced layer consists of a contamination layer including several kinds of metals and a layer having crystal defects was certainly formed near the wafer surfaces, the width of the influenced layers was only 3μm, and the layer could be easily removed by the grinding process. Furthermore, characteristics of Schottky barrier diodes (SBDs) fabricated with removing the influenced layer formed by WEDM are comparable to those fabricated with using conventional wafers.

Download Full-text

Study on Finishing Cut with Dry WEDM

Materials Science Forum ◽

10.4028/www.scientific.net/msf.532-533.273 ◽

2006 ◽

Vol 532-533 ◽

pp. 273-276 ◽

Cited By ~ 3

Author(s):

Tong Wang ◽

Xin Fu Zhang ◽

Xue Fang Zhao

Keyword(s):

Surface Roughness ◽

Surface Quality ◽

Electrical Discharge ◽

Material Removal ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Lower Surface ◽

Wire Electrical Discharge Machining ◽

Dry Wedm

Utilizing gas as the dielectric instead of dielectric liquid has enabled the development of dry wire electrical discharge machining (WEDM) technology for finishing cut. This paper studies on the surface quality of tool steel with WEDM method, which is conducted in gas to improve the accuracy of finishing cut, and compares the surface quality in atmosphere and in water. Experiment results showed that Low-Speed WEDM in atmosphere offers advantages such as better straightness, lower surface roughness and shorter gap length, but WEDM in atmosphere has poorer material removal rate than conventional WEDM in water. It was also found the removal rate in atmosphere can be improved by increasing the wire winding speed.

Download Full-text