Wire EDM

Wire EDM cuts precise 2D/3D contours in conductive materials using a moving wire electrode, achieving tight tolerances and sharp internal corners regardless of hardness.

Overview

Wire EDM (wirecut EDM, EDM wire cutting) uses a continuously fed tensioned wire and electrical discharges to cut through conductive materials with no mechanical forces. It excels at intricate profiles, sharp internal corners, and tight tolerances in very hard materials like tool steels, carbide, and superalloys. Typical wire diameters around 0.008–0.012" produce narrow kerfs and very accurate geometry.

Use wire EDM for low to medium volumes where accuracy, edge quality, and geometry matter more than cycle time. It is ideal for punches and dies, mold inserts, precision tooling, and parts that would be impossible or very expensive to mill. Expect excellent dimensional accuracy, no burrs, and good surface finishes with multiple skim cuts. Limitations: it only works on conductive materials, usually requires a through-cut path (or start hole), is relatively slow per part, and part cost grows with cut length and thickness. Large flat surfaces and coarse-tolerance features are usually not cost-effective to EDM.

Common Materials

  • Tool steel A2
  • Tool steel D2
  • Carbide
  • Titanium Grade 5
  • Inconel 718
  • Aluminum 6061

Tolerances

±0.0002" to ±0.0005"

Applications

  • Punch and die profiles
  • Extrusion and draw dies
  • Injection mold inserts and cores
  • Medical and micro-mechanism components
  • Precision gears and splines
  • Fixture details and precision shims

When to Choose Wire EDM

Choose wire EDM for complex 2D profiles, sharp internal corners, or tight-tolerance features in hard or delicate conductive materials. It fits low to medium volumes where high accuracy, fine edges, and no burrs outweigh longer cycle times. It is especially suited for tooling, dies, and parts with geometry that is difficult or impossible to machine with rotating cutters.

vs Sinker EDM

Pick wire EDM when you need through-cuts or complex flat profiles with sharp internal corners and tight positional accuracy. Sinker EDM suits blind cavities and 3D pocket shapes, but wire EDM is more accurate and faster for planar outlines, punches, dies, and features that can be cut from the outside or via start holes.

vs EDM Drilling

Use wire EDM for profiling and contour cutting after any required start holes exist, whether drilled conventionally or by EDM drilling. EDM drilling is mainly for fast, straight small holes (e.g., cooling holes, start holes), while wire EDM takes over when you need precise shapes, slots, and complex perimeters linked to those holes.

vs CNC machining

Choose wire EDM when you need internal sharp corners, very small radii, thin walls, or extremely hard materials that would require special cutters or create deflection in milling. CNC machining is faster for bulk material removal and 3D surfaces, but wire EDM wins on accuracy and geometry for planar profiles and delicate features.

vs Laser cutting

Select wire EDM when edge quality, tolerance, and heat-affected zone must be tightly controlled in thick or hard metals. Laser cutting is much faster for sheet and plate, but wire EDM delivers better tolerances, no HAZ, and superior fit for precision tooling and close-fitting components.

vs Waterjet cutting

Use wire EDM for high-precision parts in hard metals where tight tolerances, fine features, and burr-free edges are critical. Waterjet handles a wider material range and higher throughput, but wire EDM offers smaller kerf, better dimensional control, and cleaner edges for precision dies, molds, and tooling details.

Design Considerations

  • Keep stock thickness and material type clearly specified; cut time and cost scale with thickness and hardness
  • Call out tight tolerances only where functionally required; every extra 0.0001" of tolerance increases setup and skim passes
  • Design internal corners with at least the wire radius (typically ≥0.005") and specify if true sharp corners are functionally required
  • Provide or specify start holes when possible and note any features that cannot be broken out to avoid surprise drilling operations
  • Avoid very long, continuous fine-detail profiles on thick parts unless necessary; segmenting or simplifying contours reduces cut time and cost
  • Indicate whether parts can be stack-cut from plate; stacking multiples dramatically improves cost per piece for flat profiles