II. How to set machining conditions

"Ⅰ. About electric discharge machining"

"III. How to design electrodes"

2. Elements of machining performance

Machining performance changes by machining conditions. Elements representing the machining performance are as follows.

1) Removal rate

"Removal rate" refers to the speed that the spark removes the workpiece. Units of [g/min] (weight) and [mm3/min] (volume) are used. Generally, in machining conditions of high "removal rate", sparks become strong and surface becomes rough.

2) Electrode wear ratio

"Electrode wear ratio" refers to the amount of electrode wear for the amount of removal of the workpiece in ratios. Percent [%] is used for the unit.
Generally, machining condition with small "electrode wear ratio" tends to make removal rate slow down.

3) Machining surface roughness

"Machining surface roughness" refers to the state of the unevenness of the surface after the workpiece has been removed by sparks. The unit [Ra] is used. The smaller "machining surface roughness" is, the lower removal rate becomes.

4) Discharge gap

"Discharge gap" refers to the amount of clearance between the electrode and the workpiece. Unit [mm] is used. "Discharge gap" by strong spark grows large.


These four elements change by contents of the setting of machining conditions. Many kinds of machining conditions are made and used depending on the demand of various machining contents.