energy is required to melt the work-piece surface
energy is required to melt the work-piece surface
to form a through hole and this leads to a longer
to form a through hole and this leads to a longer
machining time. Longer machining times results
machining time. Longer machining time results
in a lower MRR. Therefore, MRR decreases
in a lower MRR. Therefore, MRR decreases
with thicker work-pieces. The diameter of the
with thicker work-pieces. The diameter of the
electrode only marginally influences the MRR.
electrode only marginally influences the MRR.
With an increase in diameter, there is a possibility
With an increase in diameter, there is a possibility
that more electrons are excited and jump off the
that more electrons are excited and jump off the
electrode to form an electrical spark. The nominal
electrode to form an electrical spark. The nominal
capacitance applied is the stored charge that
capacitance applied is the stored charge that
excites free electrons in the electrode to provide
excites free electrons in the electrode to provide
the emission of electrons to the work-piece.
the emission of electrons to the work-piece.
Higher capacitance provides more electrical
Higher capacitance provides more electrical
discharge energy and hence a higher MRR. When
discharge energy and hence a higher MRR. When
the feed rate increases, the electrode tool reaches
the feed rate increases, the electrode tool reaches
the surface of the work-piece faster and gives a
the surface of the work-piece faster and gives a
shorter machining time. Therefore, machining time
shorter machining time. Therefore, machining time
increases with the increase in feed rate.
increases with the increase in feed rate.
Electrode Wear Ratio (EWR)
Electrode Wear Ratio (EWR)
EWR is always affected by thermal erosion and the
EWR is always affected by thermal erosion and the
flushing process of the electrode tool during the
flushing process of the electrode tool during the
EDM process (D’Urso & Merla, 2014). The trend of
EDM process (D’Urso & Merla, 2014). The trends
the graph shows that (Fig. 11 - 15):
of the graphs show that (Figures 11 - 15):
EWR decreases with the change of work-
● ●
EWR decreases with the change of work-
piece material from brass to stainless steel;