EDM Wire

Tensile Strength
This is the maximum load-bearing capability of the material relating to its ability to resist stretching and fracturing. The measure is determined by the maximum load in pounds per square inch divided by the cross-sectional area of the wire. The benefits of a high tensile EDM wire includes that it provides a better edge straightness which is advantageous for single-pass parts and for small and fine-diameter wires to reduce breakage. High tensile wire aides in geometric accuracy, part straightness and provides a superior skim cut.

Fracture resistance
It is more accurate to refer to fracture resistance as toughness or resilience as there is no standardised index or rating for fracture resistance in EDM wire. When talking of the fracture resistance of EDM wire, it is the ability of the wire to resist the effects of the process of EDM. Having a more resistant wire reduces instances of deviations and breaking, which can significantly impact auto-threading and the overall productivity of an EDM machine.

Conductivity
In EDM, the higher the wires’ conductivity, the more power can be delivered to the workpiece increasing efficiency and cutting speed.

Vaporisation temperature
In machining on a micro scale, space is a commodity. Having a low melting/vaporisation temperature in the EDM wire allows for greater flushability of by-products of the process. It is beneficial that the wire surface vaporises rapidly to avoid contamination of the electrode gap.

Hardness
Not to be confused with tensile strength, the hardness (or temper) of a wire refers to the wires ductility, or its ability to endure elongation. EDM wires are categorised as either soft or hard and are better suited to different machining types. On closed-guard machines, a hard wire threads better than a softer wire but a soft wire may be more suited to a taper-cut, for example. Auto-threading is an important innovation in EDM and hard wires provide higher rates of reliability in auto-threading than its softer counterparts.