The principle of low-speed wire EDM wire cutting

Thu May 05 10:56:12 CST 2022

Water quality working fluid is used for low-speed wire EDM. Water has a certain conductivity, and even if it is deionized to reduce the conductivity, there is still a certain number of ions. When the workpiece is connected to the positive electrode, under the action of the electric field, OH- ions will continue to accumulate on the workpiece, causing oxidation and corrosion of iron, aluminum, copper, zinc, titanium, and tungsten, and making the binder in the cemented carbide material—cobalt to form The ionic state dissolves in water, forming a "softening layer" on the surface of the workpiece. Measures to increase the resistivity (from tens of thousands of ohms? cm to hundreds of thousands of ohms? cm) have been used to reduce the ion concentration as much as possible. Although it has played a certain role in improving the surface quality, it still cannot be effectively and completely solved." Softening layer" problem.

Anti-electrolysis power supply is an effective technical means to solve the "softening layer" of the workpiece. The anti-electrolysis power supply adopts alternating pulses, and the average voltage is zero, so that the OH-ion electrode wire in the working fluid and the workpiece are in an oscillating state, not tending to the workpiece and the electrode wire, and preventing the oxidation of the workpiece material.

The use of anti-electrolysis power supply for WEDM can control the surface metamorphic layer to be less than 1μm, avoid the precipitation and dissolution of cobalt in the cemented carbide material, and ensure the life of the cemented carbide mold.