# Principles and Characteristics of Different EDM Processes in Machining Tool and Die Steels
## 4 Research in EDM of Tool Steel
### Performance Measures in EDM of Tool Steels
\\  & & & & Selecting proper working \\  & & & & parameters improved MRR by 85\%. \\  & & & & SR was not deteriorated even at \\  & & & & MRR. Adding Span 20 (30 g/L) \\  & ([PERSON] et al. & & & decreases both the concentrated \\
17 & 2009) & EDM & Ip, PD, V, and & MRR and SR \\
17 & [159] & EDM & Vg & MRR and SR \\  & & & & discharge phenomenon. \\  & & & & The thickness of recast layer on \\  & & & & the workpiece of kerosene was less \\  & & & & than the thickness of pure kerosene. \\  & & & & The surfactant increased \\  & & & & the conductivity of kerosene and \\  & & & & shorted the delay time, thus \\  & & & & improved the machining efficiency. \\ \hline  & & & & The factors most influencing \\  & & & & the cost-effectiveness of the EDT \\
18 & (Matoorian & & & process were intensity, spindle \\  & (Matoorian & & & speed, servo, and pulse-on time in \\  & (Matoorian 2008) & EDM & IN, Ton, Toff, V, S, and W & MRR \\  & ([PERSON] 2008) & EDM & I, EM, and & MRR \\  & ([PERSON] 2008) & EDM & D\_tool & MRR \\  & & & D\_tool & MRR \\  & \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Authors** & **Process** & **Process** & **Machining** & **Remarks** \\ \hline
23 & [115] & & & & MRR in powder-mixed EDM was significantly affected by peak current, concentration of the silicon powder, pulse-on time, pulse-off time, and gain. Among all, peak current and concentration of silicon powder were the parameters most influencing MRR. The optimum c parameters were peak current = 10 A, powder concentration = 4 g/L, pulse-on time = 100 μs, pulse-off time = 15 μs, and gain = 1 mm/s. \\ \hline
24 & [164] & & & The SR increases as pulsed current and pulse time increase. SR decreases as current and pulse time decrease and pulse pause time increases. For rough EDM machining, the machine power should be 25\% of the produced power with current, pulse time, and pulse pause time of 16 A, 6 μs, and 3 μs, respectively. For finish machining, the machine had 50\% of produced power with current, pulse time, and pulse pause time of 8 A, 6 μs, and 3 μs, respectively. \\ \hline
25 & [154] & & & 81.5\% of the high-speed EDM process variance was due to pulse time, duty cycle, and peak value of discharge current. The best parameter combinations achieving precision and accuracy of the high-speed EDM process were open-circuit voltage of 12 μs, duty cycle of 66\%, pulse-peak current of 12 A, powder concentration of 0.5 cm\({}^{3}\)/L, regular distance for electrode lift of 12 mm, time interval for electrode lift of 0.6 μs, and powder size of 40 μm. \\ \hline
26 & [27] & EDM &
\begin{tabular}{c} Pulse-on time, current, and \\ pre-EDM roughing as factors, along with pulse-on time/current, pulse-on time/pre-EDM roughing, and current/pre-EDM roughing as interactions, were found to have significant effects on electrode wear of the EDM process of DIN 1.2714. \\ \end{tabular} \\ \hline
27 & [27] & EDM & \begin{tabular}{c} Is, PD, PI, FR, \\ and GC \\ \end{tabular} & \
\begin{tabular}{c} EWR, better \\ SR, and ER \\ \end{tabular} &
\begin{tabular}{c} Providing a selection tool enables an unskilled user to select necessary parameters which achieve less electrode wear, better surface quality, and high erosion rate for both finish and rough machining. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No. ** & **Authors** & **Process** & **Process** & **Machining** & **Remarks** \\ \hline  & & & & The surface roughness of the workpiece in the EDM process was improved by adding surfactant and aluminum powder to the dielectric fluid. The EDM parameters which achieved optimal surface roughness (0.172 \(\upmu\)m) were Al powder concentration of 0.1 g/L, positive polarity, peak current of 0.3 A, peak duration of 1.5 \(\upmu\)s, and surfactant concentration of 0.25 g/L. The gap distance was increased by adding aluminum powder or surfactant to the EDM dielectric fluid. Dielectric mixed with both aluminum powder and surfactant achieved an optimally thin recast layer.