scholarly journals Enhancement of Surface Quality of AISI-D3 Steel after Electrical Discharge Machining (EDM) with Aluminium Powder Mixed in the Dielectric

Electrical Discharge Machining is an advanced machining method with various advantages, as a result of which, its use is becoming more & more widespread. This process is one of the modern machining processes which is characterized by the absence of plastic deformation and chip formation. The advancement of this process may further be enhanced by utilizing powder particles within dielectric medium that is designated as Powder Mixed Electrical Discharge Machining (PMEDM) process. In the current study, to enhance the surface roughness (SR) of AISI-D3 tool steel using Copper and Brass as electrode and Aluminium (Al) as powder by utilising PMEDM process, an experimentation has been carried out. During experimentation, pulse on and off time, peak current and powder concentration are considered as input process parameters. From the experimental results, it is noted that with mixing of aluminium powder in dielectric medium, surface roughness has increased significantly. Moreover, it is seen that powder concentration of 1 g/l at 1 A peak current giving better surface quality of AISI-D3 steel. This indicates the enhancement of Electrical Discharge Machining (EDM) performance dispersing aluminium powder in dielectric fluid.

2008 ◽  
Vol 53-54 ◽  
pp. 387-392 ◽  
Author(s):  
Tong Wang ◽  
Yu Mei Lu ◽  
Shu Qiang Xie ◽  
Shuang Shuang Hao ◽  
H. Zhao

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.


2006 ◽  
Vol 532-533 ◽  
pp. 273-276 ◽  
Author(s):  
Tong Wang ◽  
Xin Fu Zhang ◽  
Xue Fang Zhao

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.


Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1018
Author(s):  
Ziliang Zhu ◽  
Dengji Guo ◽  
Jiao Xu ◽  
Jianjun Lin ◽  
Jianguo Lei ◽  
...  

Titanium-nickel shape memory alloy (SMA) has good biomedical application value as an implant. Alloy corrosion will promote the release of toxic nickel ions and cause allergies and poisoning of cells and tissues. With this background, surface modification of TiNi SMAs using TiC-powder-assisted micro-electrical discharge machining (EDM) was proposed. This aims to explore the effect of the electrical discharge machining (EDM) parameters and TiC powder concentration on the machining properties and surface characteristics of the TiNi SMA. It was found that the material removal rate (MRR), surface roughness, and thickness of the recast layer increased with an increase in the discharge energy. TiC powder’s addition had a positive effect on increasing the electro-discharge frequency and MRR, reducing the surface roughness, and the maximum MRR and the minimum surface roughness occurred at a mixed powder concentration of 5 g/L. Moreover, the recast layer had good adhesion and high hardness due to metallurgical bonding. XRD analysis found that the machined surface contains CuO2, TiO2, and TiC phases, contributing to an increase in the surface microhardness from 258.5 to 438.7 HV, which could be beneficial for wear resistance in biomedical orthodontic applications.


Author(s):  
Ze Yu ◽  
Dunwen Zuo ◽  
Yuli Sun ◽  
Guohua Li ◽  
Xuemei Chen ◽  
...  

To simultaneously optimize the surface quality and machining efficiency of the electrical discharge machining (EDM) processes used to produce titanium alloy quadrilateral group small hole parts, a combined “EDM + AFM” machining technology is proposed in this paper as an efficient and high-quality machining approach. In the proposed method, TC4 titanium alloy is first machined using the EDM process with graphite electrodes and the abrasive flow machining (AFM) process is then used to finish the machined surface. The effects of various electrical parameters on EDM-derived surface quality and improvements in EDM-derived quality under the application of AFM were assessed and, using the final surface roughness as a constraint condition, the effects of various combinations of EDM and “EDM + AFM” on efficiency were studied. The results revealed that the thickness and surface roughness of the superficial recast layer of the TC4 titanium alloy increase with both current and pulse width; in particular, increasing these parameters can increase the surface roughness by two to three grades. Following AFM, the alloy has a more uniform hardness distribution and the surface stress state changes from tensile to compressive stress, indicating that the combined “EDM + AFM” machining scheme can significantly enhance the surface quality of EDM-produced titanium alloy quadrilateral small group holes. The combined scheme achieves a balancing point beyond which increasing the roughness or the number of machining holes enhances either the machining efficiency or the machining surface quality. In the case of typical titanium alloy quadrilateral group small hole parts, the combined machining process can improve the finishing efficiency and total machining efficiency by 71.2% and 25.36%, respectively.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5943
Author(s):  
Arminder Singh Walia ◽  
Vineet Srivastava ◽  
Mayank Garg ◽  
Nalin Somani ◽  
Nitin Kumar Gupta ◽  
...  

In electrical discharge machining (EDM), the machined surface quality can be affected by the excessive temperature generation during the machining process. To achieve a longer life of the finished part, the machined surface quality plays a key role in maintaining its overall integrity. Surface roughness is an important quality evaluation of a material’s surface that has considerable influence on mechanical performance of the material. Herein, a sintered cermet tooltip with 75% copper and 25% titanium carbide was used as tool electrode for processing H13 steel. The experiments have been performed to investigate the effects of EDM parameters on the machined surface roughness. The findings show that, as the pulse current, pulse length, and pulse interval are increased, the surface roughness tends to rise. The most significant determinant for surface roughness was found to be pulse current. A semi-empirical surface roughness model was created using the characteristics of the EDM technique. Buckingham’s theorem was used to develop a semi-empirical surface roughness prediction model. The semi-empirical model’s predictions were in good agreement with the experimental studies, and the built empirical model based on physical features of the cermet tooltip was tested using dimensional analysis.


2000 ◽  
Vol 2000.53 (0) ◽  
pp. 49-50
Author(s):  
Rikio HIKIJI ◽  
Yoshihiro KAWANO ◽  
Koji ABURADA ◽  
Masakazu HARADA ◽  
Minoru ARAI

2021 ◽  
Author(s):  
Aboulfazl Taherkhania ◽  
Mohsen Asghari Ilani ◽  
Faramarz Ebrahimi ◽  
Phan Huu Nguyen ◽  
Long Banh Tien ◽  
...  

Abstract It is very essential to form such high stregth and hard-to-cut materials by using modern machining methods. It is important to introduce the efforts on modification of the process for improving the machining quality. In the present investigation, an effort was made to analyze the effects of micro size aluminium particles mixed dielectric medium under different powder concentration on machining titanium alloy in electro erosion process. The response-surface-methodology(RSM) based algorithm was utilized to analyze the performance measures by considering machinning time with Cost of Goods Manufactured (COGM) method in PMEDM process. It was found that the micron size powders can significantly help to enhance the surface quality of the Ti-6Al-4V surface during machining in EDM process. The presence of carbon, oxygen elements and the formation of surface oxides and carbides has been found due to the decomposition of dielectric fluid in PMEDM process. The lower deep cavities and uniform machining surface have been produced with the aluminum oxide powder EDM process owing to lower surface cracks density, conductivity. To sum up, investigation and comparison of surface scanning showed that this setting has been implied could be considered by the industries needs more precision.


Author(s):  
Kursad Gov ◽  
Omer Eyercioglu

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.


Author(s):  
Gangadharudu Talla ◽  
Soumya Gangopadhyay ◽  
CK Biswas

In recent times, nickel-based super alloys are widely utilized in aviation, processing, and marine industries owing to their supreme ability to retain the mechanical properties at elevated temperature in combination with remarkable resistance to corrosion. Some of the properties of these alloys such as low thermal conductivity, strain hardening tendency, chemical affinity, and presence of hard and abrasives phases in the microstructure render these materials very difficult-to-cut using conventional machining processes. In this work, an experimental setup was developed and integrated with the existing electrical discharge machining system for carrying out powder-mixed electrical discharge machining process for Inconel 625. The experiments were planned and conducted by varying five different variables, that is, powder concentration, peak current, pulse-on time, duty cycle, and gap voltage based on the central composite design of response surface methodology. Effects of these parameters along with powder concentration were investigated on various surface integrity aspects including surface morphology, surface roughness, surface microhardness, change in the composition of the machined surface, and residual stress. Results clearly indicated that addition of powder to dielectric has significantly improved surface integrity compared to pure dielectric. Among the powders used, silicon has resulted in highest microhardness, that is, almost 14% more than graphite. Lowest surface roughness (approximately 50% less than pure kerosene) and least residual stress were obtained using silicon powder (approximately 8% less than graphite-mixed dielectric). Relative content of nickel was reduced at the expense of Nb and Mo after addition of powders like aluminum and graphite in dielectric during electrical discharge machining.


2016 ◽  
Vol 874 ◽  
pp. 15-21 ◽  
Author(s):  
Xiao Shuang Rao ◽  
Fei Hu Zhang ◽  
Chen Li

With some conductivity and low grinding affectivity, a hybrid machining process termed electrical discharge diamond grinding (EDDG) is applied to the precision machining of reaction bonded silicon carbide (RB-SiC) ceramic. As there is electrical spark in the hybrid machining process, the electrical parameters are varied to explore their effects on the surface quality of RB-SiC ceramic with EDDG. In this paper, the experiments of different polarity and gap voltage with EEDG were investigated, and the microstructure and surface roughness on the machined surface of RB-SiC ceramic were analyzed. The surface morphology and micro-cracks were examined with a scanning electron microscope, and the surface roughness was measured with a confocal scanning laser microscope. It is found that surface roughness initially increases and then decreases with increase of the gap voltages and is higher with negative polarity than that with positive polarity. The micromorphology Micro-cracks were observed on the surface machined and are outstanding in re-solidified zone with EDDG.


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