Characteristics of discharge parameters of graphite electrode
(1) peak current (IP)
Features: the larger the peak current, the smaller the electrode loss, the larger the surface roughness; under certain area conditions, the faster the processing speed.
When the peak current is more than 12 A, the electrode loss reaches the minimum value;
When the peak current is more than 32 A, the processing becomes unstable.
Selection criteria:
Select according to current density:
Current density — the specified current value that can bear on the unit area of the electrode, which is called the current density of the electrode.
The results show that: copper electrode: 6-8 A / cm2, graphite electrode: 5-7 A / cm2
(2) pulse width (on)
Definition: pulse width is the duration of the voltage pulse applied to both ends of the discharge gap on the electrode and workpiece.
Features: the larger the pulse width, the smaller the electrode loss and the larger the surface roughness; under certain current conditions, the faster the processing speed.
When the peak current is less than 12 A, the machining speed increases with the increase of pulse width
When the peak current is more than 16 A, the machining speed decreases with the increase of pulse width
The results show that when the pulse width is more than 150 μ s, the loss of graphite electrode can be reduced to less than 1%, and the target of low loss machining can be achieved, but not more than 420 μ s
