Wire electrical discharge machining, also known as slow wire EDM, is a numerical control machine tool that uses continuously moving fine metal wire (commonly copper wire, referred to as electrode wire) as an electrode to ablate metal and cut workpieces by means of pulse spark discharges that produce temperatures above 6,000 degrees Celsius. The principle of slow wire EDM is the phenomenon of continuous discharging to remove metal that exists between the online electrode and the workpiece due to the presence of a segmented gap.

Due to the slow wire electrocuting machine's continuous wire feeding method using wire electrodes, which are processed during movement, even if the wire electrodes are worn, they can be continuously replenished, thus improving part processing accuracy. The surface roughness of the workpieces processed by the slow wire electrocuting machine typically reaches Ra=0.8μm or higher, and the roundness error, straightness error, and size error of the slow wire electrocuting machine are significantly better than those of the rapid wire electrocuting machine. Therefore, the slow wire electrocuting machine is widely used in the processing of high-precision parts. In addition to small and medium-sized enterprises in the early stages, it is also extremely common in processing factories of large enterprises such as aviation and automotive industries.