scholarly journals Surface and Subsurface Quality of Titanium Grade 23 Machined by Electro Discharge Machining

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 164
Author(s):  
Panagiotis Karmiris-Obratański ◽  
Emmanouil L. Papazoglou ◽  
Beata Leszczyńska-Madej ◽  
Krzysztof Zagórski ◽  
Angelos P. Markopoulos

Electrical Discharge Machining (EDM) is a non-traditional cutting technology that is extensively utilized in contemporary industry, particularly for machining difficult-to-cut materials. EDM may be used to create complicated forms and geometries with great dimensional precision. Titanium alloys are widely used in high-end applications owing to their unique intrinsic characteristics. Nonetheless, they have low machinability. The current paper includes an experimental examination of EDM’s Ti-6Al-4V ELI (Extra Low Interstitials through controlled interstitial element levels) process utilizing a graphite electrode. The pulse-on current (IP) and pulse-on time (Ton) were used as control parameters, and machining performance was measured in terms of Material Removal Rate (MRR), Tool Material Removal Rate (TMRR), and Tool Wear Ratio (TWR). The Surface Roughness (SR) was estimated based on the mean roughness (SRa) and maximum peak to valley height (SRz), while, the EDMed surfaces were also examined using optical and SEM microscopy and cross-sections to determine the Average White Layer Thickness (AWLT). Finally, for the indices above, Analysis of Variance (ANOVA) was conducted, whilst semi-empirical correlations for the MRR and TMRR were given using the Response Surface Method (RSM). The results show that the pulse-on time is the most significant parameter of the machining process that may increase the MRR up to 354%. Pulse-on current and pulse-on time are shown to have an impact on the surface integrity of the finished product. Furthermore, statistics, SEM, and EDX images on material removal efficiency and tool wear rate are offered to support the core causes of surface and sub-surface damage. The average microhardness of the White Layer (WL) is 1786 HV.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 303
Author(s):  
Panagiotis Karmiris-Obratański ◽  
Emmanouil L. Papazoglou ◽  
Beata Leszczyńska-Madej ◽  
Krzysztof Zagórski ◽  
Angelos P. Markopoulos

Electrical Discharge Machining (EDM) consists of a non-conventional machining process, which is widely used in modern industry, and especially in machining hard-to-cut materials. By employing EDM, complex shapes and geometries can be produced, with high dimensional accuracy. Titanium alloys, due to their unique inherent properties, are extensively utilized in high end applications. Nevertheless, they suffer from poor machinability, and thus, EDM is commonly employed for their machining. The current study presents an experimental investigation regarding the process of Ti–6Al–4V ELI with high power EDM, using a graphite electrode. Control parameters were the pulse-on current (Ip) and time (Ton), while Machining performances were estimated in terms of Material Removal Rate (MRR), Tool Material Removal Rate (TMRR), and Tool Wear Ratio (TWR). The machined Surface Roughness was calculated according to the Ra and the Rt values, by following the ISO 25178-2 standards. Furthermore, the EDMed surfaces were observed under optical and SEM microscopy, while their cross sections were also studied in order the Average White Layer Thickness (AWLT) and the Heat Affected Zone (HAZ) to be measured. Finally, for the aforementioned indexes, Analysis Of Variance was performed, whilst for the MRR and TMRR, based on the Response Surface Method (RSM), semi-empirical correlations were presented. The scope of the current paper is, through a series of experiments and by employing statistical tools, to present how two main machining parameters, i.e., pulse-on current and time, affect major machining performance indexes and the surface roughness.


Author(s):  
Arun Kumar Rouniyar ◽  
Pragya Shandilya

Magnetic field assisted powder mixed electrical discharge machining is a hybrid machining process with suitable modification in electrical discharge machining combining the use of magnetic field and fine powder in the dielectric fluid. Aluminum 6061 alloy has found highly significance for the advanced industries like automotive, aerospace, electrical, marine, food processing and chemical due to good corrosion resistance, high strength-to-weight ratio, ease of weldability. In this present work, magnetic field assisted powder mixed electrical discharge machining setup was fabricated and experiments were performed using one factor at a time approach for aluminum 6061 alloy. The individual effect of machining parameters namely, peak current, pulse on time, pulse off time, powder concentration and magnetic field on material removal rate and tool wear rate was investigated. The effect of peak current was found to be dominant on material removal rate and tool wear rate followed by pulse on time, powder concentration and magnetic field. Increase in material removal rate and tool wear rate was observed with increase in peak current, pulse on time and a decrease in pulse off time, whereas, for material removal rate increases and tool wear rate decreases up to the certain value and follow the reverse trend with an increase in powder concentration. Material removal rate was increased and tool wear rate was decreased with increase in magnetic field.


2015 ◽  
Vol 14 (03) ◽  
pp. 189-202 ◽  
Author(s):  
V. Vikram Reddy ◽  
P. Madar Valli ◽  
A. Kumar ◽  
Ch. Sridhar Reddy

In the present work, an investigation has been made into the electrical discharge machining process during machining of precipitation hardening stainless steel PH17-4. Taguchi method is used to formulate the experimental layout, to analyze the effect of each process parameter on machining characteristics and to predict the optimal choice for each electrical discharge machining process parameters namely, peak current, pulse on time and pulse off time that give up optimal process performance characteristics such as material removal rate, surface roughness, tool wear rate and surface hardness. To identify the significance of parameters on measured response, the analysis of variance has been done. It is found that parameters peak current and pulse on time have the significant affect on material removal rate, surface roughness, tool wear rate and surface hardness. However, parameter pulse off time has significant affect on material removal rate. Confirmation tests are conducted at their respective optimum parametric settings to verify the predicted optimal values of performance characteristics.


2014 ◽  
Vol 592-594 ◽  
pp. 479-483 ◽  
Author(s):  
Hemant Walkar ◽  
Vijaykumar S. Jatti ◽  
T.P. Singh

Electric discharge machining (EDM) is a non-conventional machining process in which material removal take place by a series of electric spark generated between the small gap of both electrode and both immersed in dielectric medium. The gap conditions of EDM significntly affect the stability of machining process. Thus, the machining performance would be improved by removing the debris from the machining gap fastly. In view of this, the objective of present work was to investigate the effect of magnetic field on the material removal rate (MRR) and surface roughness (SR), in conjunction with the variation of electrical parameters like pulse on-off times and gap current, while keeping other electrical parameters and work piece/ tool material constant. Experimental results showed that the magnetic field assisted EDM improves the process stability. Moreover, the EDM process with high efficiency and quality of machined parts could fulfill the requirements of modern manufacturing industries.


Author(s):  
R Rajeswari ◽  
MS Shunmugam

Electrical discharge machining is used in the machining of complicated shapes in hardened molds and dies. In rough die-sinking stage, attempts are made to enhance material removal rate with a consequential reduction in cycle time. Powder mix and ultrasonic assistance are employed in the electrical discharge machining process to create gap conditions favoring material removal. In the present work, experiments are carried out on hardened D3 die steel using full-factorial design based on three levels of voltage, current and pulse on time. The gap phenomena in graphite powder-mixed and ultrasonic-assisted rough electrical discharge machining are studied using a detailed analysis of pulse shapes and their characteristic trains. Two new parameters, namely, energy expended over a second ( E) and performance factor ( PF) denoting the ratio of energy associated with sparks to total discharge energy, bring out gap conditions effectively. In comparison with the conventional electrical discharge machining for the selected condition, it is seen that the graphite powder mixed in the dielectric enhances the material removal rate by 20.8% with E of 215 J and PF of 0.227, while these values are 179.8 J and 0.076 for ultrasonic-assisted electrical discharge machining with marginal reduction of 3.9%. Cross-sectional images of workpieces also reveal the influence of electrical discharge machining conditions on the machined surface. The proposed approach can be extended to different powder mix and ultrasonic conditions to identify condition favoring higher material removal.


Electrical discharge machining (EDM) is one of the oldest nontraditional machining processes, commonly used in automotive, aerospace and ship building industries for machining metals that have high hardness, strength and to make complicated shapes that cannot be produced by traditional machining techniques. The process is based on the thermoelectric energy between the work piece and an electrode. EDM is slow compared to conventional machining, low material removal rate, high surface roughness, high tool wear and formation of recast layer are the main disadvantages of the process. Tool wear rate, material removal rate and surface quality are important performance measures in electric discharge machining process. Numbers of ways are explored by researchers for improving and optimizing the output responses of EDM process. The paper summarizes the research on die-sinking EDM relating to the improvements in the output response.


2012 ◽  
Vol 445 ◽  
pp. 994-999 ◽  
Author(s):  
Mohammad Reza Shabgard ◽  
Mirsadegh Seyedzavvar

This paper details the correlation between the input parameters with the tool material on the machining response in comparison of two different combinations of toolworkpiece material, namely copper-H13 and graphite-H13. The considered machining input parameters included pulse current and pulse on-time, and the investigated characteristics of the machining response were the material removal rate, tool wear, and surface roughness of the workpiece. Furthermore, differences in pulse shapes and process stability between the copper-H13 and graphite-H13 combinations were investigated.


2014 ◽  
Vol 887-888 ◽  
pp. 1195-1199
Author(s):  
Zhi Chen ◽  
Zhen Zhang ◽  
Wu Yi Ming ◽  
Hao Huang

Wire electrical discharge machining (WEDM) is extensively used in the mold, instrument and manufacturing industries, and rough cutting operation in WEDM is treated as a challenging process because improvement of more than one machining performance measures viz. metal removal rate (MRR), roughness (Ra) are sought to obtain a precision work. In this paper, first of all, a set of Taguchi experiment (L18 21×34) is carried out based on the Taguchi method. Secondly, two groups of ANOM are completed to obtain the influence trends of each parameters on material removal rate (MRR) and roughness (Ra), respectively. Eventually, three groups of best process parameters combination are acquired to meet high material removal rate (MRR) and low roughness (Ra) simultaneously, it can provide guiding significance to actual machining process.


2015 ◽  
Vol 77 (21) ◽  
Author(s):  
Maidin S. ◽  
H.H. El Grour ◽  
Seeying C.

The electrical discharge machining (EDM) is one of non - conventional machining process where the erosion of the work piece take place based on the thermal energy between the electrode and the work piece. Due to the widely used and its availability, copper and aluminium was used in this study. These two materials was machined using die sinking EDM to study the characteristics of each material using copper electrode. Few research has been conducted to study copper electrode to machined copper work piece and this was considered as a challenge in this research. More heat was generated and more time consumed was the reason behind machining small depth in this research. The important factors such as discharge current, voltage, pulse on time and pulse off time monitored and recorded to know how these factors effect on the Material Removal Rate (MRR) and Tool Wear Ratio (TWR) of the copper and aluminium work piece material. The experiments conducted under the designed full factorial procedure where pulse on-time and pulse current are used as the input parameters. It was found that material MRR increases with increase in current and pulse duration, but MRR is higher during machining of aluminum than that of copper. In term of TWR it is found that the TWR resulting of machining copper is lower than aluminium


Author(s):  
Fereydoon Rajabinasab ◽  
Vahid Abedini ◽  
Mohammadjafar Hadad ◽  
Ramezanali Hajighorbani

This research conducts in three sections. The first section studies the effect of tool materials and gases on rotary workpiece electrical discharge machining. During the experiments, the effects of three kinds of tool materials (Cu, Cu-Cr, and Cu-Sn) and three types of industrial gases (air, argon, and CO2) on the material removal rate, tool wear rate, and workpiece surface roughness are investigated. The second is a comparison between rotary workpiece, rotary tool, and the fixed workpiece by choosing the appropriate tool material and gas in order to observe the effect of workpieces rotation on the process. Finally, another comparison has been done between wet electrical discharge machining and near dry electrical discharge machining of the fixed workpiece in order to study the effect of the dielectric. The results show the copper tool has the best performance compared with other tools. Scanning electron microscopy output shows the Cu-Sn tool creates shallow micro-cracks on the surface. Air and CO2 gases have the higher material removal rate in low current, but argon has better function than other gases in high current. In addition, a rotational speed causes an increase in material removal rate and tool wear rate and surface roughness decrease in near dry electrical discharge machining. The level of tool wear rate has decreased by 14% in the rotary workpiece compared with the rotary tool.


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