One-way wire feeding and reciprocating wire feeding WEDM both adopt the electricity inlet device in the form of conductive block. As a half of the conductive block, the electrode wire directly slides in contact with the conductive block made of superhard material, transmitting power pulses and large peak current.
Theoretically, the contact surface between them is close to linear, and the relative sliding friction velocity, that is, the wire conveying speed. The former is stable because of the low wire feeding speed, and the power pulse energy transmitted by this wire feeding method is relatively stable. When the reciprocating WEDM cuts for the first time, its sliding friction velocity is as high as 8-12m/s.
This not only causes mechanical wear of the molybdenum wire, but also causes poor contact between the two contact pairs with the high-speed movement of longitudinal and transverse wave vibration, thus easily inducing galvanic discharge between the molybdenum wire and the conductive block connected in series with the discharge gap. Once the electric erosion discharge occurs between molybdenum wire and conductive block, this pulse discharge in aerobic environment will cause the burn of molybdenum wire and the early wear of conductive block.
In addition, the electric erosion discharge between the electrode wire and the conductive block tends to become more and more serious, which eventually leads to wire fracture and conductive block ablation. In addition, the use of intelligent high-frequency pulse power supply based on discharge state sampling will also cause the instability of intelligent control function of pulse power supply.
To this end, the company launched a patent. In this patented power inlet device, a pair of special wear-resistant and corrosion-resistant materials are used to transmit high-frequency pulse energy. The pair of conductive pairs are in plane contact, and their relative rotational linear speed is only lower than 1/20 of the wire feeding speed, and high-frequency elastic devices are used to ensure reliable contact between the conductive pairs. After several years of trial use, the power inlet device has long service life and high reliability, which greatly reduces the loss of molybdenum wire.