Engineering · Comparison
Three non-traditional cutting processes — same goal, very different physics, very different sweet spots. Wire EDM cuts perimeters with a thin wire. Sinker EDM erodes pockets with a shaped electrode. Laser vaporizes through metal with focused light. Knowing which to specify saves cost and unlocks geometry the other two can't reach.
| Spec | Wire EDM | Sinker EDM | Laser |
|---|---|---|---|
| Process | Erosion via wire electrode through dielectric water | Erosion via shaped graphite/copper electrode in oil dielectric | Vaporization via focused laser beam (typically fiber) |
| Material removal | Through cuts only (perimeter) | Cavities, pockets, blind features | Through cuts; some 3D with multi-axis |
| Min internal radius | ~½ wire diameter + spark gap (≈0.0025″ with 0.004″ (0.10 mm) wire) | Electrode-tip radius (~0.001″) | Beam waist (~0.001–0.005″) |
| Surface finish (Ra) | 4–64 µin (skim passes) | 8–125 µin | 63–250 µin (ragged kerf in metal) |
| Material types | Conductive only — metal, carbide | Conductive only — metal, carbide | Most metals + many non-metals (plastic, fabric) |
| Material thickness | 0.020″ – 12″ | Up to spindle Z travel | Best < 0.5″ for clean kerf |
| Max hardness | Unlimited | Unlimited | Cuts hardened, but heat-affected zone larger |
| Recast / HAZ | Recast layer (0.0001–0.0005″) | Recast + heat-affected zone | Significant HAZ in metal cuts |
| Cost / hour | $120/hr typical | $100/hr typical | $60–80/hr (sheet metal); higher for tube/3D |
| Best for | Sharp inside corners, dies, hardened parts, thin walls | Pockets, blind cavities, complex 3D shapes | Sheet-metal cutting, thin tube, non-conductive materials |
Wire EDM
Stamping/forming dies in hardened tool steel, surgical-tool jaws, thin-wall flexures, internal corners under 0.005″. Wire radius plus spark gap sets the minimum inside corner. Cuts at the same rate hardened or soft.
Sinker EDM
Plastic injection-mold cavities, blind detail in hardened steel, complex 3D forms where milling can’t reach. Electrode (graphite or copper) is shaped to match the cavity. Slower than wire — but does things wire can’t.
Laser
Sheet-metal blanking, brackets, thin-tube cutting, non-metal cutting (plastic, gasket, fabric). Fast for volume, cheap for thin material. Less precise than wire EDM and leaves a heat-affected zone.
Outsourced to laser vendors — most cost-effective when sheet metal is the input form.
Decision rule
EDM is out — laser or water-jet only.
Sinker EDM. Wire only does perimeters; laser only does through-cuts.
Wire EDM. Mill cutter geometry can’t reach those corners; laser’s HAZ won’t hold tolerance.
Laser. Cheap, fast, good enough for general sheet work.
None of the above — mill it. EDM cuts perimeters, not volumes; it’s the wrong tool for hogging out 80% of a billet.
Keep exploring
Where wire EDM fits among manufacturing processes.
Compare the Ra each cutting process leaves behind.
What tight contour tolerances cost across processes.
Milling strategy for features EDM can't reach economically.
Estimate run time before committing to a process.
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