Two big factors influence the cutting efficiency：One is the wire carrying capacity (electric current); the other is the erosion matters in the joint-cutting which can’t be cleared in time, its electricity conduction consumed the pulse energy. Both the total energy and the energy utilization are the question of the cutting efficiency. In this industry they performed many typical tests on the cutting efficiency about high-speed wire cutting using the material by molybdenum. The result proved that, when the molybdenum wire current-carrying capacity achieved 150A/mm², its tensile strength will be reduced to 1/3~1/4 of the original, this magnitude of current is regarded as the cutting limit of the molybdenum wire current-carrying. Basis of that, the wire Ф 0.12 with 1.74A carrying capacity, Ф0.15 with 2.65A, Ф0.18 with 3.82A, namely had achieved the cutting molybdenum wire’s limit value. If increase the wire’s current-carrying capacity continually, not doubt the wire life will be shorter. As the wire’s speed with 10m/s, using the DX-1 coolant, cutting the simple steel with 50mm thickness, the pulse width with 32MS and the pulse space with 200MS, the cutting efficiency is 5.8mm3/min calculated by the erosion matter’s volume. With this efficiency computation, when the molybdenum wire with the different thickness works in the Max. current-carrying capacity, the area cutting efficiency is different, and the Ф0.12 with the cutting efficiency is 70.43mm2/ min, Ф 0.15 is 90.41mm2/ min, Calculated by this way, we can increases the current-carrying capacity by the wire’s diameter being larger, if the electric current increases, the efficiency has also been possible correspondingly to enhance. But, the fast reciprocating wire-running is not allowed (Remove wires, deflection, wear and other reasons). Enlarge the silk’s diameter to over 0.23, because the speed of discharging the erosion matters is limit, when the electric current increases to the average value of 8A, the short circuit or the arc discharge will occur in the gap, reluctantly the short-time spark discharge also causes the molybdenum wire loss sharp increasing, therefore the method only by increasing the wire’s thickness and enlarging the electric current, will not be accepted.

The erosion matter presents the function of resistance load in the gap, it short-circuited a part of the energies which flowed by the molybdenum wire to the gap. Therefore when the cutting materials is thicker, erosion matter discharge is more difficult, the energy loses more, the effective processing pulse will be less, the discharging current becomes the linear load current, could not form the processing but only heat the molybdenum wire, this is the main reason about the energy lost and the wire breakage.

According to the two main factors that influence the efficiency, some efforts as follow should be taken to raise the speed:

1’ Enlarge the single pulse energy, namely the pulse amplitude and the peak current. To get the wire carrying capacity not overload, larger pulse spacing should be adopted to make sure the average current not increase too much.

2’ Keep the dielectric coefficient and the insulation strength of the cooling fluid, and maintain higher spark explosive force and cleaning ability, reduce the short-circuit disadvantage of the corrosive stuff to the pulse to the limit.

3’ Raise the mechanical precision of wire-running system, for working more quickly through the narrow interstice than the wide, while the straight than the folding.

4’ Increase properly the wire speed to get the water that brought to the interstice by wire faster and more, so that the corrosive stuff is escaped more availably.

5’ Speed up the water driven by wire, for its better cleaning ability to the interstice

6’ Improve the frequency conversion tracing sensitivity, and increase the pulse utilization.

7’ Decrease the commutating time of the wire-running motor, start faster, and increase the effective time.