# 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
Earlier studies were also conducted to investigate the relationship between processes and performance parameters [54; 142]. The main researches in optimizing process parameters of EDM machining are summarized in Table 3.  
Figure 4: Surface morphologies of long- and short-duration pulses [202]. Figure 5: SEM microphotographs of single craters under different pulse durations [202]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**No. **} & \multirow{2}{*}{**Authors**} & \multirow{2}{*}{**Process**} & \multirow{2}{*}{**Process**} & \multirow{2}{*}{**Machining**} & \multirow{2}{*}{**Remarks**} \\  & & & & & & SR was higher when using Dura \\  & & & & & & graphite than when using Poco \\  & & & & & graphite. As pulse current increases, \\  & ([PERSON] et al., 2015) & EDM & Is, EM, and MC & CR and RS & micro-cracks increase; soft \\  & ([PERSON] et al., 2015) & EDM & Is, EM, and MC & CR and RS & machining exhibited higher residual \\  & ([PERSON] et al., 2015) & EDM & Is, \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Authors** & **Process** & **Process** & **Machining** & **Remarks** \\  & & & **parameters** & **Performance** & **Remarks** \\ \hline  & ([PERSON] and & Die & & & & The waste vegetable oil-based \\  & Rathod & sinking & Is, Vg, Ton, & MRR, EWR, & bio-dielectric fluid can be used as an \\
2 & 2015) & EDM & and Toff & and TWR & alternate to hydrocarbon-, water-, \\  & [74] & machine & & & and synthetic-based dielectric fluids \\  & & & & & for EDM. \\ \hline  & & & & & The MRR and energy efficiency were \\  & ([PERSON] et al. & & & & much higher with short pulse \\
3 & 2014) & EDM & PD and PoW & RE, D\_plas, & durations than with long pulse \\  & [197] & & & and RE & durations. The depth–diameter ratio \\  & & & & & of the crater was higher when \\  & & & & & the workpiece was positive. \\ \hline  & & & & & The ranges of process parameters for \\  & & & & & wire EDM were established as \\
4 & Prasanthi & W EDM & Toff, Vs, Ip, & SR & follows: pulse-on time 108–128 \(\upmu\)s, \\  & 2014) & & & & pulse-off time 47–63 \(\upmu\)s, peak current \\  & [190] & & & & 11–13 A, voltage 18–68 V, wire \\  & & & & & tension 2–8 g, water pressure 8–14. \\ \hline  & (Aich and & & & & The optimal parameters (I, Ton, and \\  & [PERSON] & 2014) & EDM & I, Ton, and & Toff & MRR and \\  & [139] & & & Toff & SR \\  & & & & & the best SR were 3.0 A, 200.000 \(\upmu\)s, \\  & & & & & and 126.8332 \(\upmu\)s, respectively. \\ \hline  & & & & & For EN-8 material, the mean MRR \\  & & & & & value was (72.4 mm\({}^{3}\)/min), it was \\  & & & & & higher for the cast electrode than for \\  & & & & & the sintered electrode. The TWR \\  & & & & & was marginally lower for the cast \\  & & & & & electrode than for the sintered electrode. The mean value of SR was \\
6 & [PERSON] & EDM & Ip, Ton, DP & MRR, TWR, & the sintered electrode. For die steel \\  & 2014) & & & and SD & D3, the mean value of MRR was \\  & [118] & & & & higher for the cast electrode than for \\  & & & & & the sintered electrode. The TWR \\  & & & & & was marginally lower for the cast \\  & & & & & electrode than for the sintered \\  & & & & & electrode than for the cast electrode. \\ \hline  & & & & & The values of discharge current (Ip), \\  & & & & pulse-on time (Ton), duty factor(\(\uptau\)), & \\  & & & & and flushing pressure (Fp) that & achieved the best quality were 7 A, \\
7 & [PERSON] et al. & EDM & Ip, Ton, \(\uptau\), & MRR, TWR, & 200 us, 90\%, and 0.4 kg/m\({}^{2}\), \\  & & & and Dp & SR, and r\({}_{1}\)/r\({}_{2}\) & respectively. The optimal obtained \\  & & & & response parameters were MRR = 13.9600 mm\({}^{3}\)/min, TWR = 0.0201 & mm\({}^{3}\)/min, Ra = 4.9300 \(\upmu\)m, and \\  & & & & circularity = 0.8401. & \\ \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  & & & & Adding 30 g/L of Span 20 to \\  & & & & kerosene increased the MRR by 40\%.