Wire Feed Speed
Wire feed speed is the linear speed at which the electrode wire is delivered through a wire EDM machine, typically expressed in m/s, m/min, or mm/s. It controls how often fresh wire reaches the spark gap, balancing metal removal against wire wear. Fast wire feeding exceeds 2.5 m/s; slow wire cutting is below that. Roughing uses higher feed, finishing uses lower feed.
On the shop floor, wire feed speed is a fundamental setting on wire EDM machines because it determines how much fresh electrode material passes through the cut zone. During roughing operations, a higher wire feed keeps the spark gap clean and supports aggressive material removal, especially when cutting thick die blocks or hardened tool steel. Once the goal shifts to finishing, the machinist backs the wire feed down so the discharge stays stable and the wire does not introduce thermal disturbance into the spark gap. The right feed setting is not chosen in isolation; it must be coordinated with pulse width, pulse interval, power, wire tension, and flushing so the machine holds a consistent spark gap without chatter, lag, or breakage. In mold and die work, these adjustments are made between the rough cut and skim passes to control taper, reduce recast layer effects, and protect the final tolerance.
- Mixing feed rates: Operators sometimes treat wire feed speed like the table feed in milling, but the wire is advancing through the machine, not the workpiece. This mix-up leads to wrong parameters and poor process setup.
- High feed on finish passes: Using roughing-level wire feed during finishing increases thermal load in the spark gap, so the finish pass comes out with poor surface quality and heavy wire wear.
- Unit mismatch errors: A machine manual may list wire feed speed in m/s, m/min, or mm/s; entering the number without converting sends the setup wildly off and risks unstable cutting or wire breakage.
Is wire feed speed the same as cutting speed in WEDM?
No. Wire feed speed is the electrode transport rate, while cutting speed is the rate at which the machine advances through the workpiece along the programmed path.
Why is lower wire feed sometimes used for finishing?
Lower wire feed is used to reduce wire wear and thermal disturbance so the finish pass can produce better surface integrity and tighter geometry.
What happens if wire feed is too low?
The wire is consumed more slowly, which can increase local wear concentration and reduce process robustness if discharge energy is not matched properly; the machine may lose stability in demanding cuts.