It’s difficult to cut the work piece with thick thickness. It can't cut how much thickness according to rising height of the wire support. Because of the effect of discharge erosion, when reaching a certain thickness, the process is not stable to lead to short circuit and drawing arc occurs so that the wire is burnt. Under the unstable process, the groove strips appear on the cutting section, and the face is destroyed heavily.

For the steel, the thick work piece usually is over 200mm in thickness; for the higher conducting and temperature resistance material like copper, cement carbide, pure tungsten and molybdenum, is about 70mm.

Why it’s difficult to cut the thick work piece as below:

1’ There is no enough fluid entering and exchanging to clean well the erodent matter, can’t recover the insulation, so the discharge can’t occur. The obturator branches off the energy of pulse power which makes the breakdown voltage and single pulse energy not enough.

2’ The wire itself has limited carrying capacity which can’t provide more pulse energy to the joint-cutting.

3’ The long route that the erodent matter is escaped weakens the spark discharge not to create enough explosive force and disposing pollutant ability.

4’ The material of thick work piece has more possibility of impurity and tension force, has more chance of local deforming. Lose cutting impact force, but increase possibility of short circuit.

The measures to cut the thick work piece as below:

1’Increase the single pulse energy, also increase the pulse space, in order to enhance discharge energy under the

average of wire carrying capacity not enlarging.

2’ Select the coolant with high dielectric coefficient, better insulating ability and stronger flow ability and disposing pollutants ability.

3’ Widely increase the pulse voltage to enlarge discharge gap, in order to the fluid easily enter and go out.

4’ Make the pretreatment for the material such as forging, quenching and tempering.

5’ Improve the speed of wire running, keep wire running more stable, in order to enhance the resistance of short circuit and carrying capacity.