• A thin wire of brass, tungsten, or copper is used as an electrode.
• Deionized water is used as the dielectric.
• The process is similar to standard EDM,
• Slowly cuts groove in shape of wire.
• Wire is consumed and is slowly fed.
• This process is much faster than electrode EDM.
• Higher currents, and lower rest times increase the speed of this process.
• Relations between groove width and speed are shown in the graph below.
• This process is well suited to production of dies for plastic molding, progressive dies, etc.
• Summary of EDM characteristics,
- mechanics of material removal - melting and evaporation aided by cavitation
- tool materials - Cu, Brass, Cu-W alloy, Ag-W alloy, graphite
- material/tool wear = 0.1 to 10
- specific power consumption 1.8 W/mm3/min
- critical parameters - voltage, capacitance, spark gap, dielectric circulation, melting temperature
- materials application - all conducting metals and alloys
- shape application - blind complex cavities, microholes for nozzles, through cutting of non-circular holes, narrow slots
- limitations - high specific energy consumption (about 50 times that in conventional machining); when forced circulation of dielectric is not possible, removal rate is quite low; surface tends to be rough for larger removal rates; not applicable to nonconducting materials